From Alaska to Chiapas:
The First North American Parasitology Congress
THE FIRST NORTH AMERICAN MEETING OF
AMERICAN SOCIETY OF PARASITOLOGISTS,
SOCIEDAD MEXICANA DE PARASITOLOGÍA,
& PARASITOLOGY SECTION OF THE
CANADIAN SOCIETY OF ZOOLOGISTS
Hyatt Regency
Mérida Hotel,
Mérida, México
June 21–25, 2007
THANK Y
OU!
YOU!
The American Society of Parasitologists (ASP),
the Sociedad Mexicana de Parasitología (SMP),
and the Parasitology Section of the Canadian Society of Zoologists (PS-CSZ)
gratefully acknowledge these companies and foundations
for their support and sponsorship of
the First North American Parasitology Congress.
CORPORA
TE SPONSORS
CORPORATE
AEROPUERTO INTERNACIONAL DE MÉRIDA, ASUR S.A. DE C.V.
BIO-RAD, MÉXICO DF, MÉXICO
CAMARA NACIONAL DE LA INDUSTRIA DE LA TRANSFORMACIÓN (CANACINTRA) DELEGACIÓN,
YUCATÁN, MÉRIDA, YUCATÁN, MÉXICO
CENTRO DE INVESTIGACIÓN Y DE ESTUDIOS AVANZADOS DEL IPN, UNIDAD MÉRIDA, MÉRIDA, YUCATÁN,
MÉXICO
CONSEJO ESTATAL DE CIENCIA Y TECNOLOGÍA DEL GOBIERNO DE YUCATÁN (CONCYTEY), MÉRIDA,
YUCATÁN, MÉXICO
CONSEJO NACIONAL DE CIENCIA Y TECNOLOGÍA (CONACYT), MÉXICO DF, MÉXICO
CONTINENTAL AIRLINES, INC.
EMBREX, DURHAM, NC, USA
FACULTAD DE MEDICINA, UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICO (UNAM), MÉXICO DF,
MÉXICO
GOBIERNO DE YUCATÁN, MÉRIDA, YUCATÁN, MÉXICO
H. AYUNTAMIENTO DE MÉRIDA, YUCATÁN, MÉXICO
INSTITUTO TECNOLÓGICO DE MÉRIDA, MÉRIDA, YUCATÁN, MÉXICO
LAS CERVEZAS MODELO DEL SURESTE S. A. DE C. V., MÉRIDA, YUCATÁN, MÉXICO
MÉXICANA DE AVIACIÓN S. A. DE C.V.
NOVUS INTERNATIONAL, INC., ST. LOUIS MO, USA
PRODUCTOS DE HARINA DONDE S.A. DE C.V., MÉRIDA, YUCATÁN, MÉXICO
REFRESQUERA DE YUCATÁN S.A. DE C.V., MÉRIDA, YUCATÁN, MÉXICO
REPOSTERÍA FINA TERE CAZOLA S.A. DE C.V., MÉRIDA, YUCATÁN, MÉXICO
SCHERING–PLOUGH ANIMAL HEALTH, SUMMIT NJ, USA
SECRETARÍA DE DESARROLLO RURAL Y PESCA DEL GOBIERNO DEL ESTADO DE YUCATÁN, MÉRIDA,
YUCATÁN, MÉXICO
SECRETARÍA DE EDUCACIÓN PÚBLICA DEL GOBIERNO DEL ESTADO DE YUCATÁN, MÉRIDA, YUCATÁN,
MÉXICO
UNIVERSIDAD AUTÓNOMA DE YUCATÁN (UADY), MÉRIDA, YUCATÁN, MÉXICO
UNIVERSIDAD MARISTA, MÉRIDA, YUCATÁN, MÉXICO
VETECH LABORATORIES, INC., GUELPH, ONTARIO, CANADA
2
Scientific Program Committee
Local Organizing Committee
Ana Flisser Steinbruch (SMP)
Donald W. Duszynski (ASP)
Guadalupe Ortega Pierres (SMP)
Patricia Talamás Rohana (SMP)
Victor Manuel Vidal Martínez
Ma. Leopoldina Aguirre Macedo
Rossanna del Pilar Rodríguez Canul
Reyna Rodríguez Olayo
Felipe Torres Acosta
Sergio Guillén Hernández
Hugo Antonio Ruiz Piña
Eduardo Alfonso Rebollar Téllez
Roberto Cedillo Rivera
the First North American Meeting of
American Society of Parasitologists,
sociedad Mexicana de parasitología,
& Parasitology section of the
canadian Society of Zoologists
From Alaska to Chiapas:
The First North American
Parasitology Congress
Hyatt Regency
Mérida Hotel,
Mérida, México
June 21–25, 2007
3
Time
JUNE 21 (Thursday)
8:00 a.m. – Noon
2:15 – 4:00 p.m.
4:00 – 4:30 p.m.
4:30 – 6:30 p.m.
7:30 – 10:30 p.m.
riday)
JUNE
(Friday)
UNE 22 (F
8:00 a.m – 12:30 p.m.
8:30 – 11:00 a.m.
9:00 – 11:00 a.m.
9:00 – 11:00 a.m.
9:00 – 11:00 a.m.
9:00 – 11:00 a.m.
11:00 – 11:30 a.m.
11:30 a.m. – 12:30 p.m.
11:30 a.m. – 12:30 p.m.
12:30 – 2:30 p.m.
2:30 – 3:00 p.m.
3:00 – 4:30 p.m.
3:00 – 4:30 p.m.
3:00 – 4:30 p.m.
3:00 – 4:30 p.m.
3:00 – 4:30 p.m.
3:00 – 4:30 p.m.
4:30 – 5:00 p.m.
5:00 – 6:00 p.m.
5:00 – 7:30 p.m.
7:30 – 8:30 p.m.
8:30 – 10:00 p.m.
JUNE 23 (Saturday)
8:00 a.m – 12:30 p.m.
8:30 – 10:45 a.m.
9:00 – 11:00 a.m.
9:00 – 11:00 a.m.
9:00 – 11:00 a.m.
9:00 – 11:00 a.m.
11:00 – 11:30 a.m.
11:30 a.m. – 12:30 p.m.
11:30 a.m. – 12:45 p.m.
12:30 – 2:30 p.m.
2:30 – 3:00 p.m.
3:00 – 4:30 p.m.
3:00 – 6:00 p.m.
3:00 – 6:00 p.m.
3:00 – 5:45 p.m.
3:00 – 5:00 p.m.
3:00 – 5:15 p.m.
4
Activity/F
unction
Activity/Function
Meeting Room
ASP Council Meeting
ASP & SMP Presidents’ Addresses
Break
ASP President’s Symposium
Welcoming Reception
Uxmal 1-2
Regency 2-3-4
8
8
Regency 2-3-4
Hotel Pool Area
9
9
Poster Session-1 Set Up
Regency 1
ASP Student Paper Competition-1
Uxmal 1-2
Symposium 2: Parasite Genome
Regency 2
Symposium 3: Freshwater Fish Parasites
in North America
Regency 3
Symposium 4: Drug Resistance &
Chemotherapy
Regency 4
Symposium 5: Signaling
Chichén Itzá 1-2
Coffee Break
Preconvene Area
Plenary Session 1
Regency 2
ASP Student Paper Competition-2
Regency 3
Poster Session-1 & Lunch
Regency 1
Coffee Break
Preconvene Area
Removal of Posters (Session-1)
Regency 1
Ecology-1
Regency 2
Biochemistry, Genetics, Molecular
Biology-1
Regency 3
Host–Parasite Interactions-1
Regency 4
Taxonomy, Systematics, Phylogeny-1
Chichén Itzá 1-2
ASP Student Paper Competition-3
Uxmal 1-2
Break
Eminent Parasitologist Lecture
Regency 2-3
Auction Set Up
Regency 3-4
(Regency 3 after 6:00 p.m)
ASP–SMP Auction Preview
Regency 3-4
ASP–SMP Auction
Regency 3-4
Poster Session-2 Set Up
ASP Student Paper Competition-4
Symposium 6: Proteomics
Symposium 7: Innate Immunity
Symposium 8: Malaria Vectors
Symposium 9: Water-borne Parasites
Coffee Break
Plenary Session 2
Ecology-2
Poster Session-2 & Lunch
Coffee Break
Removal of Posters (Session-2)
Immunology-1
Ecology-3
ASP Student Paper Competition-5
Genetics, Molecular Biology-2
Chemotherapy, Drug Resistance
Regency 1
Uxmal 1-2
Regency 2
Regency 3
Regency 4
Chichén Itzá 1-2
Preconvene Area
Regency 2
Regency 3
Regency 1
Preconvene Area
Regency 1
Regency 2
Regency 3
Regency 4
Chichén Itzá 1-2
Uxmal 1-2
Page No.
9
9
10
11
11
11
12
12
13
19
19
19
20
21
21
22
22
22
22
23
23
24
24
25
25
25
26
32
33
33
35
36
36
Time
Activity/F
unction
Activity/Function
Meeting Room
JUNE 23 (Saturday
(Saturday,, continued)
7:00 – 10:00 p.m. Folkloric Ballet of the
University of Yucatán
JUNE 24 (Sunday)
8:00 a.m – 12:30 p.m.
9:00 – 11:00 a.m.
9:00 – 11:00 a.m.
Page No.
Central Courtyard,
University of Yucatán
37
Regency 1
Regency 2
38
38
9:00 – 11:00 a.m.
9:00 – 11:00 a.m.
11:00 – 11:30 a.m.
11:30 a.m. – 12:30 p.m.
11:30 a.m. – 12:30 p.m.
11:30 a.m. – 12:30 p.m.
11:30 a.m. – 12:30 p.m.
12:30 – 2:30 p.m.
2:30 – 3:00 p.m.
3:00 – 4:30 p.m.
3:00 – 5:00 p.m.
3:00 – 6:00 p.m.
3:00 – 6:00 p.m.
3:00 – 5:30 p.m.
7:00 – 10:00 p.m.
Poster Session-3 Set Up
Symposium 10: Paleoparasitology
Symposium 11: Parasite Problems in
Wild, Domestic or Cultured Hosts
Symposium 12: Coccidosis Conference
Symposium 13: ASP–SMP Students
Coffee Break
Plenary Session 3
Host–Parasite Interactions-2
Life Cycles, Epidemiology-1
Taxonomy, Systematics, Phylogeny-2
Poster Session-3 & Lunch
Coffee Break
Removal of Posters (Session-3)
Immunology-2
Host–Parasite Interactions-3
Life Cycles, Epidemiology-2
Taxonomy, Systematics, Phylogeny-3
Banquet
Regency 3
Chickén Itzá 1-2
Regency 4
Preconvene Area
Regency 2
Regency 3
Regency 4
Chickén Itzá 1-2
Regency 1
Preconvene Area
Regency 1
Regency 2
Regency 3
Regency 4
Chickén Itzá 1-2
Quinta Montes Molina
38
39
39
48
48
49
50
51
52
JUNE 25 (Monday)
9:00 – 10:00 a.m.
10:00 – Noon
10:00 – Noon
Bueding/Von Brand Lecture
ASP Awards & Business Meeting
SMP Awards & Business Meeting
Regency 3-4
Regency 3-4
Regency 2
52
52
53
39
40
40
41
41
u
5
HY
ATT REGENCY MÉRID
A HO
TEL
HYA
MÉRIDA
HOTEL
Floor Plans
6
FOR Y
OUR INFORMA
TION
YOUR
INFORMATION
Registration
(Main Lobby, near the gazebo behind the Hyatt Registration desk)
1:00–5:00 p.m., Thursday, June 21
8:00 a.m.–5:00 p.m., Friday, June 22
8:00 a.m.–5:00 p.m., Saturday, June 23
Speak
er Ready Room (Loltún)
Speaker
8:00 a.m.–5:00 p.m., Thursday, Friday, Saturday and Sunday
Coffee Breaks (Preconvene Area)
Friday, Saturday and Sunday
11:00–11:30 a.m. and 2:30–3:00 p.m.
Poster Sessions (Regency 1)
Poster Sessions with Lunch:
Friday, Saturday and Sunday, 12:30–2:30
Set Up: 8:00–12:30 each day
Removal: 3:00–4:30 each day
Room Locations
Loltún
Regency 1, 2, 3 & 4
Chickén Itzá 1-2
Uxmal 1-2
First Floor
Second Floor
Second Floor
Second Floor
Welcoming Reception (Hotel Pool Area)
Thursday evening from 7:30–10:30 p.m.
Other Meetings
Friday, June 22
10:30 p.m.– (
ASP–SMP Student Social, Mambo Café
Saturday, June 23
7:00–8:30 a.m.
ASP Journal of Parasitology Editorial Board Breakfast, Chichén Itzá 1-2
Symbol Usage
† denotes a Student Competition Paper (ASP Oral and SMP Poster).
Ground T
ransportation
Transportation
Transportation from the airport to the hotel: The airport is about 15 km from the Hyatt. The
Local Organizing Committee (LOC) will provide ground transportation from the airport to the
Hyatt from noon June 20 to midnight June 21. The bus will be available every hour outside the
airport. There is also a 24-hour taxi service from the airport costing ~$13.50 USD one way.
LOC telephone numbers are: ++52 9999 009646 (Victor Vidal), ++ 52 9999 009633 (Leo
Aguirre), and ++52 9991 592598 (Reyna Rodríguez).
7
THURSDAY MORNING, JUNE 21
8:00–Noon
ASP COUNCIL MEETING, Uxmal 1-2.
Presiding:
S.G. Kayes, University of South Alabama, Mobile AL, USA
THURSDAY AFTERNOON, JUNE 21
2:15–2:30
FORMAL WELCOME TO MÉXICO, TO MÉRIDA, AND TO ALL PARTICIPANTS, Regency 2-3-4.
Presiding:
V.M. Vidal-Martínez and L. Aguirre-Macedo, CINVESTAV, Mérida, Yucatán, México
Welcome:
DR. ANA FLISSER, SMP President,
Microbiologia y Parasitologia,
Facultad de Medicina, UNAM,
México DF, México
DR. STEPHEN KAYES, ASP President,
University of South Alabama,
Mobile AL, USA
DR. JOSÉ NARRO, Director, Faculty of Medicine, UNAM, México DF, México
DR. JOSÉ ANTONIO DE LA PEÑA, Director Adjunto de Desarrollo Científico y
Académico, CONACYT
2:30–4:00
ASP & SMP PRESIDENTS’ ADDRESSES, Regency 2-3-4.
2:30
WELCOME. V.M. Vidal-Martínez and M.L. Aguirre-Macedo.
2:40
INTRODUCTION OF SMP PRESIDENT ANA FLISSER, UNAM, México DF,
México.
D. Correa, Instituto Nacional de Pediatria, SSA, México DF, México
Time
Paper
No.
2:50
1
3:20
8
A NATIONAL MODEL FOR THE CONTROL OF A PARASITIC DISEASE:
HUMAN CYSTICERCOSIS IN MEXICO. A. Flisser*, J. Narro, J. Calderón and G.
Martínez.
INTRODUCTION OF ASP PRESIDENT STEPHEN G. KAYES, University of
South Alabama, Mobile AL.
R.E. Kuhn, Wake Forest University, Winston-Salem NC, USA
3:30
2
CONVENTIONAL WISDOM AND A TALE OF TWO CYTOKINES. S.G. Kayes.
4:00–4:30
BREAK.
4:30–6:30
SYMPOSIUM 1: ASP PRESIDENT’S SYMPOSIUM, Regency 2-3-4.
Presiding:
S.G. Kayes, University of South Alabama, Mobile AL, USA
Theme:
Global Climate Change and Parasitic Infections.
Time
Paper
No.
4:30
3
GLOBAL CLIMATE CHANGE: CAUSES AND CONSEQUENCES. T.M. Hall.
5:00
4
CLIMATE CHANGE AND PARASITISM IN ARCTIC AND SUBARCTIC ECOSYSTEMS. S.J. Kutz*, R. Peacok and D. Bender.
5:30
5
CLIMATE CHANGE, VECTOR-BORNE AVIAN DISEASES AND ENDEMIC
HAWAIIAN FOREST BIRDS—WHAT WILL THE FUTURE BRING? C.T.
Atkinson*, B.L. Woodworth, D.A. Lapointe and M.D. Samuel.
6:00
6
CLIMATE CHANGE AS A DRIVER OF INFECTIOUS DISEASE CHANGE. K.D.
Lafferty.
THURSDAY EVENING, JUNE 21
7:30–10:30 WELCOMING RECEPTION, Pool Area.
FRIDAY MORNING, JUNE 22
8:00–12:30 POSTER SESSION-1: SET UP, Regency 1.
Authors of posters numbered 39–113 set up their posters.
8:30–11:00 ASP STUDENT PAPER COMPETITION-1, Uxmal 1-2.
Presiding:
L. Couch, The University of New Mexico, Albuquerque NM, USA
R. Rodríguez-Canul, CINVESTAV, Mérida, Yucatán, México
Time
Paper
No.
8:30
7†
PROTEOMIC ANALYSIS OF SPOROZOITES REVEAL HIGHLY CONSERVED
TRAP-LIKE MOLECULES IN TWO STRAINS OF EIMERIA MAXIMA M6 AND
GS. S.A. El-Ashram* and J.R. Barta.
8:45
8†
PARASITE COMMUNITIES DISCERN DISTINCT PACIFIC SARDINE
(SARDINOPS SAGAX) POPULATIONS IN THE CALIFORNIA CURRENT. R.E.
Baldwin* and K.C. Jacobson.
9
9:00
9†
LIFE-HISTORY COST OF TREMATODE INFECTION IN HELISOMA ANCEPS
USING MARK-RECAPTURE IN CHARLIE’S POND. N.J. Negovetich* and G.W.
Esch.
9:15
10†
THE ENERGETIC COSTS OF PARASITISM IN AN INTERMEDIATE HOST. S.E.
Lettini* and M.V. Sukhdeo.
9:30
11†
PATTERNS OF EUGREGARINE DIVERSITY IN DAMSELFLIES IN FOUR
EAST TEXAS PONDS. J.C. Garcia*, T.J. Cook and R.E. Clopton.
9:45
12†
PREDICTING WEST NILE VIRUS (WNV) DYNAMICS USING LOCAL HABITAT CHARACTERISTICS. W.D. Rossiter*, M. Vitullo and M.V. Sukhdeo.
10:00
13†
POPULATION DYNAMICS OF DAUBAYLIA POTOMACA (NEMATODA:
RHABDITIDA) IN HELISOMA ANCEPS. L.E. Camp*, N.J. Negovetich, G.W.
Esch and H.E. Eure.
10:15
14†
HOW LARGE IS THE HAND INSIDE THE PUPPET? THE EVOLUTIONARY
ECOLOGY OF INFECTION MASS OF 15 TREMATODE PARASITIC CASTRATORS OF THE ESTUARINE SNAIL, CERITHIDEA CALIFORNICA. R.F.
Hechinger*, K.D. Lafferty, F.T. Mancini III and A.M. Kuris.
10:30
15†
COPROLOGICAL AND SEROLOGICAL DIAGNOSIS OF ANOPLOCEPHALA
PERFOLIATA INFECTION IN SOUTHERN ALBERTA (CANADA) HORSES:
PRELIMINARY DATA. S.L. Skotarek*, C.P. Goater and D.D. Colwell.
10:45
16†
LIFE CYCLE VARIATION IN THE GENUS RHABDIAS: A TALE OF SNAKES
AND FROGS. G.J. Langford* and J. Janovy, Jr.
9:00–11:00 SYMPOSIUM 2: PARASITE GENOME, Regency 2.
Presiding:
R. Hernández, UNAM, México DF, México
K. Miska, ARS, USDA, Beltsville MD, USA
Time
Paper
No.
9:00
17
THE GENOME PROJECT OF TAENIA SOLIUM. A. Garcia-Rubio, R.J. Bobes,
J.C. Carrero-Sánchez, M.A. Cevallos, K. Estrada, J.L. Fernández, G. Fragoso, P.
Gaytán, V.M. González, L. Jiménez, V.M. José, M.S. Juárez, A. Landa, C.
Larralde, L. Mendoza, J. Morales-Montor, E. Morett, E.L. Sciutto, X. Soberón, P.
De La Torre, V. Valdés, J. Yánez and J.P. Laclette*.
9:30
18
PARASITIC NEMATODES—FROM GENOMES TO CONTROL. M. Mitreva*, Y.
Yin, J. Martin, S. Abubucker and R. Wilson.
10:00
19
A MULTIDISCIPLINARY APPROACH TO UNDERSTANDING THE ROLE OF
SAND FLY PROTEINS IN LEISHMANIA TRANSMISSION. J.G. Valenzuela*, F.
Oliveira, J.M. Anderson, S. Kamhawi, R. Jochim, C. Teixeira, R. Gomes, D.
Elnaiem and N. Collin.
10:30
20
COMPARATIVE GENOMICS OF PARASITIC PROTISTS: BETTER THE BUG
YOU KNOW. J.M. Carlton.
10
9:00–11:00 SYMPOSIUM 3: FRESHWATER FISH PARASITES IN NORTH AMERICA,
Regency 3.
Presiding:
G. Pérez-Ponce de León, UNAM, México DF, México
A. Choudhury, St. Norbert College, DePere WI, USA
Time
Paper
No.
9:00
21
COLONIZATION OF FRESHWATER FISHES BY INTRODUCED PARASITES.
W.F. Font.
9:30
22
NORTH AMERICAN FRESHWATER FISHES AND THEIR PARASITES: PATTERNS AND PROCESSES IN BIOGEOGRAPHY. A. Choudhury.
10:00
23
HELMINTH DISEASES IN AQUACULTURE, WITH AN EMPHASIS ON CATFISH, NEMATODES AND TREMATODES. R.M. Overstreet.
10:30
24
PARASITES, FOOD WEBS AND ECOSYSTEM STRESS. D.J. Marcogliese.
9:00–11:00 SYMPOSIUM 4: DRUG RESISTANCE AND CHEMOTHERAPY,
Regency 4.
Presiding:
P. Mendoza de Gives, CENID-PAVET-INIFAP, Jiutepec, Morelos, México
E.S. Loker, The University of New Mexico, Albuquerque NM, USA
Time
Paper
No.
9:00
25
PERTURBING THE DIMER INTERFACE OF TRIOSEPHOSPHATE ISOMERASE AND ITS EFFECT ON TRYPANOSOMA CRUZI. V. Olivares-Illana, A.
Rodríguez-Romero, I.D. Becker, M. Berzunza-Cruz, J. García, N. Cabrera, F.
López-Calahorra, M. Tuena De Gómez-Puyou, A. Gómez-Puyou and R. PérezMontfort*.
9:30
26
ANTIPARASITIC DRUG DISCOVERY VIA MECHANISM-BASED SCREENING:
WILL IT SUCCEED? T.G. Geary.
10:00
27
UNDERSTANDING THE DIRECT AND INDIRECT EFFECTS OF SUPPLEMENTARY FEEDING TO REDUCE THE NEED FOR ANTHELMINTIC TREATMENTS IN SMALL RUMINANTS. J.F. Torres-Acosta*, A.J. Aguilar-Caballero,
C.A. Sandoval-Castro and H. Hoste.
10:30
28
MECHANISMS AND MARKERS OF MACROCYCLIC LACTONE RESISTANCE
IN NEMATODE PARASITES OF HUMANS AND ANIMALS. R. Prichard.
9:00–11:00 SYMPOSIUM 5: SIGNALING, Chichén Itzá 1-2.
Presiding:
B. Espinoza, UNAM, México DF, México
J. Hawdon, George Washington Medical Center, Washington DC, USA
11
Time
Paper
No.
9:00
29
TLR2 ACTIVATION IN NK CELLS OF PATIENTS INFECTED WITH LEISHMANIA MEXICANA. I.D. Becker*, I.C. Cañeda-Guzmán, E.A. Fernandez-Figueroa,
N.L. Salaiza-Suazo and M.M. Aguirre-Garcia.
9:30
30
PROINFLAMMATORY RESPONSES TO MALARIA INFECTION AND CELL
SIGNALING MECHANISMS. C.D. Gowda.
10:00
31
ACTIN STRUCTURAL ORGANIZATION IN ENTAMOEBA HISTOLYTICA
TROPHOZOITES BY FIBRONECTIN SIGNALING. P. Talamás-Rohana*, A.
Rios, V. Hernández-Ramírez and J.L. Rosales-Encina.
10:30
32
MOLECULAR SIGNALING IN LARVAL SCHISTOSOMA MANSONI: GENE
PROFILING THE MIRACIDIUM-TO-SPOROCYST TRANSITION. T.P. Yoshino.
11:00–11:30 COFFEE BREAK, Preconvene Area.
11:30–12:30 PLENARY SESSION 1, Regency 2.
Presiding:
J. Figueroa, CENID-PAVET-INIFAP, Jiutepec, Morelos, México
A.M. Kuris, University of California, Santa Barbara CA, USA
Time
Paper
No.
11:30
33
CAVEOLIN-1 AND CHOLESTEROL PLAY A MAJOR ROLE IN THE DEVELOPMENT OF TRICHINELLA SPIRALIS OOCYTES. M.G. Ortega-Pierres.
12:00
34
POCKET GOPHERS AND CHEWING LICE: NEW DISCOVERIES IN AN OLD
SYSTEM. M.S. Hafner.
11:30–12:30 ASP STUDENT PAPER COMPETITION-2, Regency 3.
Presiding:
R.S. Seville, University of Wyoming, Casper WY, USA
V.M. Vidal-Martínez, CINVESTAV-IPN, Mérida, Yucatán, México
Time
Paper
No.
11:30
35†
REEF FISHES HAVE HIGHER PARASITE DIVERSITY AT UNFISHED
PALMYRA ATOLL COMPARED TO FISHED KIRITIMATI ISLAND. K.D.
Lafferty, J.C. Shaw* and A.M. Kuris.
11:45
36†
FOOD WEB STABILITY DRIVES PARASITE SPECIES DIVERSITY. T.K. Anderson* and M.V. Sukhdeo.
12:00
37†
PARASITES OF FISHES FROM THE COLORADO RIVER AND SELECTED
TRIBUTARIES IN GRAND CANYON, ARIZONA. C. Linder*, T. Hoffnagle, B.
Persons, A. Choudhury and R. Cole.
12
12:15
38†
LEAVING THE NEST: THE GENETIC DISTRIBUTION OF PARASITES IN
SNAILS THAT SERVE AS FIRST AND SECOND INTERMEDIATE HOSTS. J.T.
Detwiler* and D.J. Minchella.
FRIDAY AFTERNOON, JUNE 22
12:30–2:30 POSTER SESSION-1 AND LUNCH, Regency 1.
Authors stand by their posters.
SMP STUDENT POSTER COMPETITION
39†
PATTERN OF PROTEIN CARBONYLATION FOLLOWING OXIDATIVE STRESS IN
TRYPANOSOMA CRUZI. R. Martínez-Espinosa*, I. Martínez and B. Espinoza.
40†
CHARACTERIZATION AND EVALUATION OF AN ANTIGENIC EXTRACT FOR
DIAGNOSIS OF TRYPANOSOMA CRUZI INFECTION IN SERA BY ELISA ASSAY.
PRELIMINARY RESULTS. M.I. Bucio-Torres, E. Torres-Gutiérrez, E. Amador-Gaytán *,
M. Cabrera-Bravo, A.L. Ruiz-Hernández, Y. Guevara-Gómez, L. Ruiz-González, J. RojoMedina, G.S. García-De La Torre, L. González-López, G.E. Rojas-Wastavino, M.O.
Vences-Blanco, M. Gutiérrez-Quiroz and P.M.S. Salazar-Schettino.
41†
CLONING AND PURIFICATION OF A PROTEIN PHOSPHATASE 2C FROM LEISHMANIA MEXICANA. A. Navarrete-Mena*, N. Cabrera-González, R. Pérez-Montfort,
I.D. Becker and M.M. Aguirre-García.
42†
MECHANISMS OF ACTION OF DEHYDROEPIANDROSTERONE ON ENTAMOEBA
HISTOLYTICA. C. Cervantes-Rebolledo*, E. Saavedra-Lira, M. Nequiz, J.P. Laclette and
J.C. Carrero-Sánchez.
43†
IDENTIFICATION OF SURFACE PROTEINS OF TRYPOMASTIGOTES OF MEXICAN
STRAINS OF TRYPANOSOMA CRUZI. M. Martínez-Velasco*, H. Lanz-Mendoza, G.
Hurtado and B. Espinoza-Gutiérrez.
44†
DISTRIBUTION OF CYTOSKELETAL PROTEINS IN FLAME CELLS OF TAENIA
SOLIUM CYSTICERCI. L.E. Valverde Islas*, O.A. Reynoso Ducoing, E. Vega Munguía
and J.R. Ambrosio-Hernández.
45†
EHADH IS AN ENTAMOEBA HISTOLYTICA SURFACE BRO1 DOMAIN-CONTAINING PROTEIN INVOLVED IN VESICLE BIOGENESIS. C. Bañuelos*, G. GarcíaRivera, I. López-Reyes, S. Castellanos-Castro, L. Mendoza, A. González-Robles and E.
Orozco.
46†
TRICHINELLA SPIRALIS OOCYTE MATURATION IS INHIBITED BY CYCLOSPORIN
A IN RATS INFECTED WITH THIS PARASITE. R. Hernández-Bello*, R.M. BermúdezCruz, R. Fonseca-Liñán, P. García-Reyna, P. Boireau and M.G. Ortega-Pierres.
47†
LEISHMANIA MEXICANA-SPECIFIC ANTIGENS FOR SEROLOGIC DIAGNOSIS. N.
Robles-Briones*, A. Ruiz-Remigio and I.D. Becker.
48†
IN VIVO EFFICACY OF NITAZOXANIDE AGAINST TOXOPLASMA GONDII. M.
Galvan-Ramírez, G. Sánchez González *, L.R. Rodríguez Pérez, R.A. Franco Topete and
M.A. Ramirez Herrera.
13
49†
PROTEOMICAL EVALUATION OF NEW POTENTIAL BENZIMIDAZOLE DERIVATIVES AGAINST GIARDIA INTESTINALIS. C.A. Méndez-Cuesta*, L. VelázquezMárquez, M.A. Dea-Ayuela, R. Castillo-Bocanegra, F. Hernández-Luis, M.A. HernándezCampos, L. Yépez-Mulia, F. Bolás-Fernández, O.A. Reynoso-Ducoing and J.R.
Ambrosio-Hernández.
50†
IN VITRO ANTHELMINTIC ACTIVITY OF PLANT EXTRACTS FROM TROPICAL
TANNINIFEROUS TREES AGAINST TRICHOSTRONGYLUS COLUBRIFORMIS. M.A.
Alonso-Díaz*, J.F. Torres-Acosta, C.A. Sandoval-Castro, A.J. Aguilar-Caballero and H.
Hoste.
51†
VARIATION IN THE P-GLYCOPROTEIN (PGP) GENE FROM ONCHOCERCA VOLVULUS MEXICAN ISOLATES. S. González-Guzmán*, G. Sánchez-Tejeda, J. Méndez-Galvan
and A. Monroy-Ostria.
52†
COMMUNITIES OF HELMINTH PARASITES OF BUFO MARINUS (LINNAEUS, 1758)
AND BUFO VALLICEPS (WIEGMANN, 1833) (ANURA: BUFONIDAE) IN THE LAGUNAS DE YALAHAU, YUCATÁN. J.F. Espinola-Novelo* and S. Guillén-Hernández.
53†
BEHAVIORAL DISRUPTION ON FIDDLER CRAB, UCA SPECIOSA (IVES, 1891),
CAUSED BY HEXAGLANDULA CORYNOSOMA (TRAVASSOS, 1915) IN THE
CHUBURNÁ LAGOON, NORTHERN YUCATÁN PENINSULA: A PROGRESS REPORT. R.A. Pérez-Campos* and S. Guillén-Hernández.
54†
PRELIMINARY REPORT OF THE GENETIC TYPING OF ECHINOCOCCUS GRANULOSUS IN MÉXICO. D.E. Jiménez-González*, U. Rodríguez-Prado, A. López-Saavedra,
L. Herrera, C. Mondragon, P. Mata, A. Flisser, J.J. Martínez-Maya and P.J. MaravillaCampillo.
55†
DIAGNOSIS OF LYMNAEA SNAIL INFECTION BY FASCIOLA HEPATICA USING
DUPLEX-PCR. C.P. Rico-Torres*, I. Cruz-Mendoza, H. Quiroz-Romero, L.B. OrtízAlegría and D. Correa.
56†
TRYPANOSOMA CRUZI SHSP16: THE FIRST MEMBER OF THE ALPHA-CRYSTALLIN-SMALL HEAT SHOCK PROTEIN FAMILY IN TRYPANOSOMATIDS. D. PérezMorales*, P. Ostoa-Saloma and B. Espinoza.
57†
IDENTIFICATION OF EHBLM, A PUTATIVE DNA HELICASE IN ENTAMOEBA
HISTOLYTICA. M.S. Charcas-López*, C. López-Camarillo, M. López-Casamichana and
L.A. Marchat.
58†
THE ESCRT MACHINERY OF ENTAMOEBA HISTOLYTICA. I. López-Reyes*, C.
Bañuelos and E. Orozco.
59†
ENTAMOEBA HISTOLYTICA HAS THE CLEAVAGE FACTOR EHCF IM25 THAT
COULD BE INVOLVED IN PRE-MRNA 3' END POLYADENYLATION. J. FernandezRetana*, C. López-Camarillo and L.A. Marchat.
60†
PFSIR2 SILENCING COMPLEXES PURIFIED BY TANDEM AFFINITY PURIFICATION
FROM PLASMODIUM FALCIPARUM. N.K. Mita-Mendoza*, S. Martínez-Calvillo and R.
Hernández-Rivas.
61†
CHARACTERIZATION OF THE KAHRP GENE CORE PROMOTER REGION OF
PLASMODIUM FALCIPARUM. M.E. Aranda-Barradas* and R. Hernández-Rivas.
14
62†
TLR2 AND TLR4 POLYMORPHISMS AND THEIR RELATIONSHIP TO CUTANEOUS
LEISHMANIASIS. V. Becerril*, M. Berzunza-Cruz, G. Carrada-Figueroa, M. Maldonado
and I.D. Becker.
63†
POSSIBLE ROLE OF A PUTATIVE GLUCOSAMINE-6-PHOSPHATE ISOMERASE OF
ENTAMOEBA HISTOLYTICA IN THE FORMATION OF CYST-LIKE STRUCTURES. H.
Aguilar-Diaz*, J.P. Laclette and J.C. Carrero-Sánchez.
64†
TAMOXIFEN TREATMENT INDUCES PROTECTION IN MURINE CYSTICERCOSIS.
J.A. Vargas-Villavicencio*, C. Larralde, M.A. De León-Nava, G. Escobedo and J. Morales-Montor.
65†
FOLLOW-UP OF PHYSICAL DISCOMFORT AND HEALTH STATUS OF GOLDEN
HAMSTERS USED AS EXPERIMENTAL DEFINITIVE HOSTS OF TAENIA SOLIUM,
EMPLOYING TWO NON-STEROID DRUGS FOR IMMUNOSUPPRESSION. D.E.
Jiménez-González*, R. Garcia-Cortes, G. Avila-Ramirez, A. Flisser and P.J. MaravillaCampillo.
66†
PROCHRISTIANELLA SP. PARASITING THE OCTOPUS, OCTOPUS MAYA IN DZILAM
DE BRAVO, YUCATÁN, NORTHERN YUCATÁN PENINSULA. A. López-Struck* and
S. Guillén-Hernández.
67†
MIRACIDIA OF F. HEPATICA LYSES PROTEINS AND NUCLEIC ACIDS DURING
INVASION OF THE INTERMEDIATE HOSTS. L.B. Ortíz-Alegría*, C.P. Rico-Torres, I.
Cruz-Mendoza, H. Quiroz-Romero and D. Correa.
68†
EVALUATION OF TAENIA SOLIUM CALRETICULIN AS AN ORAL VACCINE IN
EXPERIMENTAL TAPEWORM INFECTION. S. León-Cabrera*, M. Cruz-Rivera, G.
Avila-Ramirez, F. Mendlovic and A. Flisser.
69†
CHARACTERIZATION OF THE ENDOCYTIC PATHWAY AND USE AS AN IRON
SOURCE OF FERRITIN BY ENTAMOEBA HISTOLYTICA. F. López-Soto*, M. ReyesLópez, N. León-Sicairos, A. González-Robles and M. de la Garza.
70†
LEISHMANIA MEXICANA INHIBITS THE APOPTOSIS IN MONOCYTE-DERIVED
DENDRITIC CELLS. L. Valdes-Reyes*, M. Berzunza-Cruz, N.L. Salaiza-Suazo, M.M.
Aguirre-Garcia, I.D. Becker, J. Moran and L. Gutiérrez-Kobeh.
71†
PARTICIPATION OF A PROTEIN TYROSINE PHOSPHATASE FROM LEISHMANIA
MEXICANA IN THE INFECTION OF MACROPHAGES. J. Gómez-Sandoval, A.
Escalona-Montaño, D. Pardavé-Alejandre, R. Cervantes, L. Gutiérrez-Kobeh, M.
Gutiérrez-Quiróz, I.D. Becker and M.M. Aguirre-García*.
72†
LEISHMANIA MEXICANA LIPOPHOSPHOGLYCAN (LPG) STIMULATES THE EXPRESSION AND FUNCTION OF NITRIC OXIDE SYNTHASE IN MURINE DENDRITIC CELLS. A. Wilkins-Rodríguez*, I.D. Becker and L. Gutiérrez-Kobeh.
73†
EFFECT OF SEXUAL AND ADRENAL HORMONES ON THE PROLIFERATION OF
ENTAMOEBA HISTOLYTICA. C. Cervantes-Rebolledo*, J. Morales-Montor, N. Moreno,
M. Nequiz, J.P. Laclette and J.C. Carrero-Sánchez.
74†
INDUCTION OF HIGH LEVELS OF TUMOR NECROSIS FACTOR α AND NITRIC
OXIDE BY VIRULENT MEXICAN STRAIN OF TRYPANOSOMA CRUZI. A. JiménezMarin* and B. Espinoza.
15
75†
MACROPHAGE MIGRATION INHIBITORY FACTOR PLAYS A ROLE IN LEISHMANIA MEXICANA INFECTION. M. Romero-Grijalva*, I. Rivera-Montoya, L.I. TerrazasValdés and M. Rodríguez-Sosa.
76†
INCREASED SUSCEPTIBILITY TO TOXOPLASMA GONDII INFECTION IN AHRNULL MICE. M. Rodríguez-Sosa*, L.I. Terrazas-Valdés, I. Rivera-Montoya, G. Elizondo
and L. Vega.
77†
TAENIA CRASSICEPS: RELEVANCE OF PARASITE GENETIC CHANGES ON THE
HOST SUSCEPTIBILITY AND IMMUNITY. G. Meneses, R.J. Bobes, E.L. Sciutto* and
G. Fragoso.
78†
LOCALIZATION OF TSOL18 AND TSOL45 IN DIFFERENT STAGES OF TAENIA
SOLIUM. J. Martínez-Ocana*, M. Garcia-De-León, C. Gauci, M. Lightowlers and A.
Flisser.
79†
PROTEIN TYROSINE PHOSPHATASE FROM ENTAMOEBA HISTOLYTICA MODULATE THE ACTIVATION OF PHAGOCYTIC CELLS. J. Espejel-Zaragoza, A. RuizRemigio, M. Nequiz, A. Escalona-Montaño, P. Talamás-Rohana and M.M. AguirreGarcía*.
80†
CHLOROQUINE HAS AN IMMUNOMODULATORY ROLE IN BALB/C MICE INFECTED WITH PLASMODIUM YOELII 17XL. A. Ramos-Avila*, J.L. Ventura-Gallegos
and M. Legorreta-Herrera.
81†
ANALYSIS OF TLR1, TLR2 AND TLR6 IN NK CELLS OF PATIENTS WITH CUTANEOUS LEISHMANIASIS. I.C. Cañeda-Guzmán*, G. Carrada-Figueroa, N.L. SalaizaSuazo and I.D. Becker.
82†
TOWARD TAENIA SOLIUM CONTROL: FIELD TRIAL EVALUATION OF THE
S3PVAC ANTI-CYSTICERCOSIS VACCINE EXPRESSED IN FILAMENTOUS PHAGES.
J. Morales*, J.J. Martínez, M. Hernández, K. Manoutcharian, G. Gevorkian, G. Acero, A.
Blancas, A. Toledo, V.M. Maza, A. Aluja, A. Fleury, G. Fragoso, C. Larralde and E.L.
Sciutto.
83†
DEVELOPMENT OF THE LIFE CYCLE OF TAENIA PISIFORMIS USING GOLDEN
HAMSTER AS THE DEFINITIVE EXPERIMENTAL HOST. E. Toral-Bastida*, P.J.
Maravilla-Campillo, A. Garza-Rodríguez, R. Garcia-Cortes, P. Palomares-Pérez, L.
Fernandez-Maya, G. Avila-Ramirez and A. Flisser.
84†
VIABILITY OF TRICHINELLA SPIRALIS RECOVERED IN MEAT SUBMITTED TO
DIFFERENT CONDITIONS OF HANDLING AND CONSERVATION. M. MedinaLerena*, A. Ramírez-Alvarez, E. Pérez-Torres, C. Pacheco-Gallardo, S. RuvalcabaBarrera and J.L.A. de la Rosa.
85†
EFFICACY OF THREE DOSES OF A MEXICAN STRAIN OF DUDDINGTONIA
FLAGRANS CHLAMYDOSPORES AGAINST HAEMONCHUS CONTORTUS LARVAE
IN SHEEP FAECAL CULTURES. N.F. Ojeda-Robertos*, P. Mendoza-De- Gives, J.F.
Torres-Acosta, A. Ayala-Burgos and A.J. Aguilar-Caballero.
86†
INFECTION DYNAMICS OF ECTOPARASITES DURING THE HATCHERY OF HYBRID TILAPIA “PARGO-UNAM.” M.D. Pérez-Fosado*, M.I. Jiménez-García, M.
Garduño-Lugo, G. Muñoz-Córdova and M.D. Castañeda-Chávez.
16
87†
TAENIA SOLIUM: ACTIVE TRANSMISSION OF PIG CYSTICERCOSIS IN SIERRA DE
HUAUTLA, MORELOS. J. Morales*, J.J. Martínez, N. Peña, V.M. Maza, N. Villalobos,
A. Aluja, A. Fleury, G. Fragoso, C. Larralde and E.L. Sciutto.
88†
PHYLOGENETIC AND BIOGEOGRAPHICAL RELATIONSHIPS OF SEVERAL POPULATIONS OF RHABDIAS SP. (NEMATODA), PARASITE OF LEPTODACTYLUS
MELANONOTUS (ANURA) FROM MÉXICO. E.A. Martínez-Salazar* and V. LeónRègagnon.
89†
GENETIC VARIATION AMONG POPULATIONS OF PHYLLODISTOMUM LACUSTRI
(LOEWEN, 1929), PARASITE OF ICTALURIDS IN NORTH AMERICA, USING SEQUENCES OF THE 28S rRNA GENE. R. Rosas-Valdez*, A. Choudhury and G. PérezPonce De León.
90†
FIRST RECORD OF SALSUGINUS ANGULARIS (MUELLER, 1934) BEVERLY-BURTON, 1984 (MONOGENEA: ANCYROCEPHALINAE) PARASITIZING GOODEINAE
FISHES (CYPRINODONTIFORMES: GOODEINAE) ENDEMIC TO MÉXICO. C.A.
Mendoza Palmero* and G. Salgado-Maldonado.
91†
ENTOMOLOGICAL INDEXES OF TRIATOMA DIMIDIATA (HEMIPTERA: REDUVIIDAE: TRIATOMINE) TO ASSESS RISK TRANSMISSION IN RURAL SAN PEDRO
CHACABAL, MOTUL, YUCATÁN, MÉXICO. I.J. May-Concha*, S.J. Carballo-González,
A. Polanco-Rodríguez, F.J. Escobedo-Ortegón, H.A. Ruiz-Piña, M.A. Barrera-Pérez and
E.A. Rebollar-Téllez.
92†
PCR ANALYSIS OF INFECTION RATES OF SANDFLY SPECIES (DIPTERA: PSYCHODIDAE: PHLEBOTOMINAE) FROM CALAKMUL, CAMPECHE, MÉXICO AND
THEIR PUTATIVE ROLE AS VECTORS OF LEISHMANIA MEXICANA
(KINETOPLASTIDA: TRYPANOSOMATIDAE). A. Pech-May*, F.J. Escobedo-Ortegón,
M. Berzunza-Cruz and E.A. Rebollar-Téllez.
93†
DEXAMETHASONE AND PGE2 MODULATION OF THE IMMUNE RESPONSE IN
FAT BODY AND MIDGUT OF ANOPHELES ALBIMANUS. F.L. García-Gil De Muñoz*,
J. Martínez Bartneche, H. Lanz Mendoza, M.H. Rodríguez López and F. HernándezHernández.
94†
THE EFFECT OF THE PROSTAGLANDINS ON THE PROTEOLITIC AND BACTERICIDE ACTIVITIES OF THE MIDGUT OF AEDES AEGYPTI MOSQUITO. M.G.
Hernández-Estrada*, F. Hernández-Hernández, F.L. Garcia-Gil De Muñoz, H. LanzMendoza and M.H. Rodríguez.
BIOCHEMISTRY
OGY
BIOCHEMISTRY,, PHYSIOL
PHYSIOLOGY
95
GENERATION OF EHGEF1 PROTEIN MUTANTS FROM ENTAMOEBA
HISTOLYTICA. N.A. Hernández-Cuevas*, A. Rojo-Domínguez, M.D. Almaraz-Barrera
and M.Á. Vargas.
96
PROTEIN CARBONYLATION IN TRYPANOSOMA CRUZI DURING DIFFERENTIATION IN VITRO. I. Martínez* and B. Espinoza.
97
IDENTIFICATION OF A CYCLOOXYGENASE–LIKE ENZYME IN LEISHMANIA
MEXICANA PROMASTIGOTES. J. Diaz-Gandarilla*, J.L. Rosales-Encina, A. Angel and
P. Talamás-Rohana.
17
98
CHARACTERIZATION OF TAENIA SOLIUM CYSTICERCI MICROSOMAL GLUTATHIONE S-TRANSFERASE ACTIVITY. G. Nava* and A. Plancarte.
99
IDENTIFICATION OF EXCRETION/SECRETION PRODUCTS DURING EVAGINATION AND IN VITRO DEGENERATION OF CYSTICERCI OF TAENIA SOLIUM. F.
Mendlovic* and A. Flisser.
100
KINETIC DETERMINATIONS TO RECOMBINANT GLUTATHIONE TRANSFERASE
OF 26.5 KDA FROM TAENIA SOLIUM. A. Torres-Rivera* and A. Landa.
101
IRON MODULATES THE DIFFERENTIAL EXPRESSION OF PROTEINASES IN
TRICHOMONAS VAGINALIS. L.D. Ramón-Luing*, L. Ávila-González and R. Arroyo.
102
ANALYSIS OF PKCβ-LIKE FROM GIARDIA DUODENALIS. M.L. Bazán-Tejeda*, R.
Argüello-García, R.M. Bermúdez-Cruz, M. Robles-Flores and M.G. Ortega-Pierres.
103
PURIFICATION OF α-MANNOSIDASES FROM ENTAMOEBA HISTOLYTICA. C.E.
Santacruz-Tinoco*, E. López-Romero and J.C. Villagomez-Castro.
CELL BIOL
OGY
BIOLOGY
104
COMPARISON OF MEMBRANE LECTINS BETWEEN NAEGLERIA FOWLERI AND
NAEGLERIA GRUBERI. A. Silva-Olivares*, I. Cervantes-Sandoval, J. Pacheco-Yepez, V.
Tsutsumi and M. Shibayama.
105
EFFECT OF CHOLESTEROL ON THE VIRULENCE OF ENTAMOEBA HISTOLYTICA.
J.M. Gutiérrez-Meza*, R. Mejia-Zepeda, V. Tsutsumi, M. Shibayama and J.J. SerranoLuna.
106
VIRULENCE BEHAVIOR OF A BRAZILIAN ISOLATE OF ENTAMOEBA DISPAR. S.
Santana-Dolabella*, J.J. Serrano-Luna, F. Navarro-Garcia, V. Tsutsumi and M.
Shibayama.
107
EHABP152, A NEW ACTIN BINDING PROTEIN FROM ENTAMOEBA HISTOLYTICA.
A.D. Campos-Parra*, M.D. Almaraz-Barrera and M.A. Vargas-Mejia.
108
SUBCELLULAR ORGANIZATION OF 11 ACTIN-LIKE AND ACTIN RELATED PROTEINS (ARPS) FROM ENTAMOEBA HISTOLYTICA. E. Guzmán-Huerta* and M.
Vargas.
109
ATLAS OF THE DEVELOPMENTAL STAGES OF TAENIA SOLIUM. F. Mendlovic*, J.
Carillo-Farga, J. Torres and A. Flisser.
110
ACTIN LOCALIZATION IN DIFFERENT STAGES OF TRYPANOSOMA CRUZI. Y.X.
Segura-Kato*, H. Merchant-Larios, R.G. Manning-Cela, M.I. López-Villaseñor, R.
Hernández and A.M. Cevallos.
111
AP3 COMPLEX AND LEISHMANIA REMODELING. C. Rhodes, F. Shaw, Jr. and J.
Porter-Kelley*.
112
ACTIN CYTOSKELETON IN ACANTHAMOEBA CASTELLANII EVIDENCED BY
MEANS OF RHODAMINE-PHALLOIDIN COMPLEX AND CRYO-ELECTRON MICROSCOPY TECHNIQUES. A. González-Robles*, G. Castañon-Gutiérrez and A.
Martínez-Palomo.
18
113
PRELIMINARY FILAMENTOUS PROTEIN STUDIES IN DIFFERENT COMPARTMENTS FROM CYSTICERCI OF TAENIA SOLIUM. O.A. Reynoso-Ducoing*, X.M.
González-Guerrero, Y. Romero-Aceff and J.R. Ambrosio-Hernández.
2:30–3:00
COFFEE BREAK, Preconvene Area.
3:00–4:30
REMOVAL OF POSTERS, Regency 1.
Authors of Poster Session-1 remove their posters (39–113).
3:00–4:30
ECOLOGY-1, Regency 2.
Presiding:
H. Quiroz-Romero, UNAM, México DF, México
K. Jacobson, Hatfield Marine Science Center, Newport OR, USA
Time
Paper
No.
3:00
114
DIPLOSTOMIASIS IN FISH FROM TRES PALOS LAGOON, GUERRERO,
MÉXICO. J. Violante-González* and A. Rojas-Herrera.
3:15
115
FISH PREDATION ON TREMATODE CERCARIAE IN A CALIFORNIA ESTUARY. A.T. Kaplan*, S.E. Halling, K.D. Lafferty and A.M. Kuris.
3:30
116
INFLUENCE OF FRESHWATER INFLOWS ON SHELLFISH RESPONSES IN
SOUTHWEST FLORIDA ESTUARIES: UTILIZING SHELLFISH RESPONSES
IN ECOSYSTEM MANAGEMENT AND RESTORATION. A.K. Volety*, G. Tolley,
L. Haynes, A. Bridges, D.J. Crean and P.H. Doering.
3:45
117
BIOINDICATORS OF CHEMICAL POLLUTION IN TROPICAL COASTAL
LAGOONS: AN INTEGRATIVE APPROACH USING FISH BIOMARKERS AND
HELMINTH PARASITES. D. Pech* and V.M. Vidal-Martínez.
4:00
118
SPATIAL DISTRIBUTION AND COEXISTENCE OF DACTILOGYRIDAE
(MONOGENEA) INHABITING WILD SPOTTED ROSE SNAPPER’S GILLS
(LUTJANUS GUTTATUS) FROM THE MAZATLÁN BAY IN MÉXICO: PRELIMINARY STUDIES. L.C. Soler Jimenéz* and E.J. Fajer-Ávila.
4:15
119
HELMINTH FAUNA OF THE GREY SNAPPER, LUTJANUS GRISEUS, ALONG
THE SOUTHERN COAST OF QUINTANA ROO, MÉXICO. D. González-Solís.
3:00–4:30
BIOCHEMISTRY, GENETICS, MOLECULAR BIOLOGY-1, Regency 3.
Presiding:
L. Roberts, Homestead FL, USA
R. Manning, CINVESTAV, México DF, México
Time
Paper
No.
3:00
120
EXPRESSED SEQUENCE TAGS (ESTS) GENERATED FROM CYSTS AND
TROPHOZOITES OF GIARDIA DUODENALIS BELONGING TO ASSEMBLAGE
A, USING SUBTRACTIVE HYBRIDIZATION. K.B. Miska*, J.M. Trout and G.H.
Rosenberg.
19
3:15
121
THE UNIQUE FATTY ACID SYNTHETIC CAPABILITY OF THE OYSTER
PARASITE, PERKINSUS MARINUS: IMPLICATION FOR CHEMOTHERAPEUTIC TREATMENT. F.E. Chu*, E.D. Lund and J.A. Podbesek.
3:30
122
A MONOADP-RIBOSYL TRANSFERASE ACTIVITY MODIFY A SECRETED
GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE IN ENTAMOEBA
HISTOLYTICA EXTRACELLULAR MEDIUM. A.H. Alvarez, G. MartínezCadena, M.E. Silva, E. Saavedra-Lira and E.E. Avila*.
3:45
123
ANALYSIS OF CYTOADHERENCE AND CYSTEINE PROTEASE ACTIVITY IN
FRESH AND LONG-TERM GROWN ISOLATES OF TRICHOMONAS
VAGINALIS AND THEIR RELATIONSHIP WITH VIRULENCE. B.A. AlvarezSandoval*, A. Rangel-Serrano, L. Caracheo-Delgado, F. Anaya-Velázquez, F.
Padilla-Vaca and J.F. Alderete.
4:00
124
ENTAMOEBA INVADENS: INHIBITORS OF PHOSPHATASES AND N-GLYCAN
PROCESSING α-GLYCOSIDASES BLOCK ENCYSTATION. L.M. AlmanzaVillegas, C.E. Santacruz-Tinoco, E. López-Romero and J.C. Villagomez-Castro*.
4:15
125
GENETIC POLYMORPHISM IN TAENIA SOLIUM CYSTICERCI RECOVERED
FROM EXPERIMENTAL INFECTIONS IN PIGS. P.J. Maravilla-Campillo*, R.
González-Guzmán, G. Zúñiga, A. Peniche, J.L. Dominguez-Alpizar, R. ReyesMontes and A. Flisser.
3:00–4:30
HOST–PARASITE INTERACTIONS-1, Regency 4.
Presiding:
J. Morales Montor, UNAM, México DF, México
G. Mayer, Virginia Commonwealth University, Richmond VA, USA
Time
Paper
No.
3:00
126
WHAT IS DELUSIONAL PARASITOSIS? (I). O.M. Amin.
3:15
127
WHAT IS DELUSIONAL PARASITOSIS? (II). O.M. Amin.
3:30
128
HOST GENETIC BACKGROUND ALTERS SEX RATIOS AND GENOTYPE
PATTERNS IN A COMPLEX-LIFE CYCLE PARASITE. M. Zavodna*, G.J. Sandland and D.J. Minchella.
3:45
129
EXPRESSION PROFILING AND BINDING PROPERTIES OF FIBRINOGENRELATED PROTEINS (FREPS), PLASMA LECTINS FROM THE SNAIL BIOMPHALARIA GLABRATA, THE INTERMEDIATE HOST OF HUMAN BLOOD
FLUKE SCHISTOSOMA MANSONI. S. Zhang*, Y. Zeng and E.S. Loker.
4:00
130
CO-INFECTION AND ITS CONSEQUENCES FOR HOST AND PARASITE LIFE
HISTORIES. G.J. Sandland*, J.K. Rodgers and D.J. Minchella.
4:15
131
TRANSCRIPTOMICS OF BIOMPHALARIA GLABRATA, SNAIL HOST OF
SCHISTOSOMA MANSONI. B. Hanelt*, C. Lun and C.M. Adema.
20
3:00–4:30
TAXONOMY, SYSTEMATICS, PHYLOGENY-1, Chichén Itzá 1-2.
Presiding:
G. Pérez-Ponce de León, UNAM, México DF, México
F. Agustin-Jiménez, University of Nebraska, Lincoln NE, USA
Time
Paper
No.
3:00
132
MORPHOLOGY SHOWS PHYLOGENETIC CONCORDANCE BETWEEN THE
GENERA OF FISH BLOOD FLUKES (DIGENEA: APOROCOTYLIDAE) AND
THE PRIMARY LINEAGES OF NON-TETRAPOD GNATHOSTOMES. S.A.
Bullard.
3:15
133
A REVIEW OF THE GENUS PATAGIFER DIETZ, 1909 (DIGENEA: ECHINOSTOMATIDAE), PARASITES OF BIRDS. A. Faltynkova*, A. Kostadinova and T.
Scholz.
3:30
134
MONOGENEOUS PARASITES FROM CENTROPOMUS UNDECIMALIS AND C.
PARALLELUS FROM TABASCO STATE. S. López-Jiménez* and L. GarciaMagaña.
3:45
135
PATHOLOGICAL AND HISTOLOGICAL CHANGES OCCURING IN THE
LIVER OF VARIOUS BIRD SPECIES INFECTED WITH THE OPISTHORCHID
TREMATODE AMPHIMERUS ELONGATUS. M.C. Sterner, III*, C. Meteyer, N.
Thomas, V. Shearn-Bochsler and R. Cole.
4:00
136
EVOLUTION OF THE FAMILY FASCIOLIDAE RAILLIET, 1895. W.M. Lofty,
S.V. Brant*, T.H. Le, A. Demiaszkiewicz, J.M. Kinsella and E.S. Loker.
4:15
137
GENETIC VARIABILITY IN MEMBERS OF DIDYMOZOIDAE FAMILY ISOLATED FROM TWO BLUEFIN TUNA SPECIES. I. Mladineo* and B. Block.
3:00–4:30
ASP STUDENT PAPER COMPETITION-3, Uxmal 1-2.
Presiding:
S. Sterner, National Wildlife Health Center, Madison WI, USA
M.V.K. Sukhdeo, Rutgers University, New Brunswick NJ, USA
Time
Paper
No.
3:00
138† TRANSMISSION DYNAMICS OF CYATHOCOTYLE BUSHIENSIS (TREMATODA: CYATHOCOTYLIDAE) AND SPHAERIDIOTREMA GLOBULUS
(TREMATODA: PSILOSTOMATIDAE) IN POOL 7 OF THE UPPER MISSISSIPPI RIVER NATIONAL WILDLIFE AND FISH REFUGE. K.K. Herrmann*
and R.E. Sorensen.
3:15
139† SPATIAL AND TEMPORAL ABUNDANCE PATTERNS OF THE COMMON
GRASS SHRIMP, PALAEMONETES PUGIO, AND THE TREMATODE PARASITE,
MICROPHALLUS TURGIDUS, IN THE NORTH CENTRAL GULF OF MÉXICO.
K.L. Sheehan*, J. O’Brien and J. Cebrian.
21
3:30
140† PATTERNS OF EUGREGARINE INFECTION IN DAMSELFLIES (ODONATA:
COENAGRIONIDAE) OF THE TEXAS BIG THICKET. S. Dahlgren*, T.J. Cook
and R.E. Clopton.
3:45
141† PATTERNS OF GREGARINE INFECTIONS OF ARGIA SPP. (ODONATA:
ZYGOPTERA) ACROSS BIOGEOGRAPHICAL PROVINCES IN TEXAS. J.J.
Hays*, T.J. Cook and R.E. Clopton.
4:00
142† GEOGRAPHICAL AND ECOLOGICAL DISTRIBUTION PATTERNS OF LEISHMANIA VECTORS IN MÉXICO. C. González-Rosas*, I.D. Becker, E. MartínezMeyer and V. Sánchez-Cordero.
4:15
143† EFFECTS OF UVB ON LARVAE OF SCHISTOSOMA MANSONI AND THE
SNAIL HOST, BIOMPHALARIA GLABRATA. D.S. Ruelas, D. Karentz and J.T.
Sullivan.
4:30–5:00
BREAK, no scheduled activities.
FRIDAY EVENING, JUNE 22
5:00–6:00
EMINENT PARASITOLOGIST LECTURE,
Regency 2-3.
Presiding:
P.M. Schantz, NCZVED, CDC, Atlanta GA,USA
Time
Paper
No.
144
THE INTERFACE BETWEEN PUBLIC HEALTH AND
PARASITOLOGY: BRIDGING THE GAP. M. Eberhard.
5:00–7:30
AUCTION SET UP, Regency 3-4.
(Regency 3 after 6 p.m.)
7:30–8:30
ASP–SMP AUCTION PREVIEW, Regency 3-4.
8:30–10:00 ASP–SMP AUCTION, Regency 3-4.
Presiding:
L. Couch, The University of New Mexico, Albuquerque NM, USA
K. Sapp, High Point University, High Point NC, USA
10:30–(
ASP–SMP Student Social, Mambo Café.
SATURDAY MORNING, JUNE 23
8:00–12:30 POSTER SESSION-2: SET UP, Regency 1.
Authors of posters numbered 177–258 set up their posters.
22
8:30–10:45 ASP STUDENT PAPER COMPETITION-4, Uxmal 1-2.
Presiding:
Time
L. Aguirre-Macedo, CINVESTAV, Mérida, Yucatán, México
J.M. Porter-Kelley, Winston–Salem State University, Winston–Salem NC, USA
Paper
No.
8:30
145† SPIRAL INTESTINE CESTODES IN THE PIKED DOGFISH (SQUALUS ACANTHIAS) ACROSS SPACE AND TIME. M. Pickering* and J.N. Caira.
8:45
146† PARASITE COMMUNITIES OF THE “CHECKERED PUFFER” SPHOEROIDES
TESTUDINEUS FROM COASTAL LAGOONS OF YUCATÁN, MÉXICO. M.T.
Sosa-Medina* and L. Aguirre-Macedo.
9:00
147† SPATIAL STRUCTURE OF THE HELMINTHS OF TONGUEFISH SYMPHURUS
PLAGIUSA ON THE CAMPECHE COAST, GULF OF MÉXICO. A. Rodríguez
González* and V.M. Vidal Martínez.
9:15
148† ASSESSING FACTORS EXERTING EVOLUTIONARY PRESSURES ON PARASITE SPECIES IN NATURE: THE CASE OF DACTYLOGYRUS. A.K. Knipes*
and J. Janovy, Jr.
9:30
149† MIGRATION AND SITE SELECTION OF ORNITHODIPLOSTOMUM PTYCHOCHEILUS METACERCARIAE IN THE OPTIC LOBES OF FATHEAD MINNOWS.
C.E. Matisz* and C.P. Goater.
9:45
150† SYSTEMATICS AND BIOGEOGRAPHY OF INDOPACIFIC BLOODFEEDING
TERRESTRIAL LEECHES (HIRUDINIDA: ARHYNCHOBDELLIDA: HIRUDINIFORMES). E. Borda* and M. Siddall.
10:00
151† A MULTI-GENE, MULTI-GENOME APPROACH TO INFERRING THE PHYLOGENY OF MEMBERS OF THE APICOMPLEXA WITH PARTICULAR REFERENCE TO THE EIMERIID AND ADELEID COCCIDIA. J.D. Ogedengbe* and
J.R. Barta.
10:15
152† MOLECULAR ANALYSIS OF ACANTHOBOTHRIUM AND ITS IMPLICATIONS
FOR GEOGRAPHIC VERSUS HOST ASSOCIATIONS AS DETERMINATES OF
CESTODE PHYLOGENY. C.A. Fyler.
10:30
153† HOMOPLASY IN BOTHRIDIAL POUCHES AND ITS IMPLICATIONS FOR
THE IDENTITY OF THE TETRAPHYLLIDEAN GENUS CARPOBOTHRIUM.
K. Christison-Lagay* and J.N. Caira.
9:00–11:00 SYMPOSIUM 6: PROTEOMICS, Regency 2.
Presiding:
Time
Paper
No.
9:00
154
F. Mendlovic, UNAM, México DF, México
V. Carruthers, Johns Hopkins University, Baltimore MD, USA
IDENTIFICATION OF PROTEINS, USING PROTEOMICS, DURING THE
EVALUATION OF POTENTIAL ANTI-PARASITIC DRUGS. J.R. Ambrosio23
Hernández*, C.A. Méndez-Cuesta, O.A. Reynoso-Ducoing, L. VelazquezMárquez, L. Ruiz-Martínez, R. Castillo, F. Hernández, A. Hernández, L. YépezMulia, M.A. Dea-Ayuela, F. Bolas-Fernández, A. Pérez-Reyes and A. Ferrer.
9:30
155
GENOME-WIDE ANALYSIS OF STAGE-SPECIFIC GENE EXPRESSION IN
LEISHMANIA. B. Papadopoulou*, A. Rochette, M. Müller, F. McNicoll, F.
Raymond, J. Corbeil and M. Ouellette.
10:00
156
A PROTEOMIC APPROACH FOR THE ANALYSIS OF IMMUNE PROTEINS IN
ANOPHELES ALBIMANUS INFECTED WITH PLASMODIUM. H. LanzMendoza*, I. Castro-Romero, P. Mercado, S. Hernández-Martínez, V. SerranoPinto, M. Rodríguez, J. Martínez-Bartneche and M.H. Rodríguez.
10:30
157
WIDE-SCALE ANALYSIS OF TOXOPLASMA INVASION PROTEIN PROCESSING. V. Lagal, E. Binder, R. Diaz, D. Chen, M. Gucek, R. Cole, K. Kim and V.
Carruthers*.
9:00–11:00 SYMPOSIUM 7: INNATE IMMUNITY, Regency 3.
Presiding:
B.E. Sánchez-Ramírez, Universidad Autónoma de Chihuahua, Chihuahua, México
M. Belosevic, University of Alberta, Edmonton, Alberta, Canada
Time
Paper
No.
9:00
158
MAST CELLS PLAY AN IMPORTANT ROLE IN THE INNATE IMMUNE RESPONSE AGAINST TRICHINELLA SPIRALIS. N. Arizmendi-Puga, J. EncisoMoreno, D. Befus, M.G. Ortega-Pierres and L. Yépez-Mulia*.
9:30
159
INNATE IMMUNITY IN INVERTEBRATES: IS PATTERN RECOGNITION
ENOUGH? E.S. Loker.
10:00
160
IMPAIRED INNATE PRO-INFLAMMATORY RESPONSE AND RESISTANCE
TO TOXOPLASMA GONDII INFECTION IN MICE LACKING MACROPHAGE
MIGRATION INHIBITORY FACTOR. M. Rodríguez-Sosa*, M. Reyes, R.
Saavedra, A.R. Satoskar and L.I. Terrazas-Valdéz.
10:30
161
HELMINTHS INDUCE T REGULATORY CELL CIRCUITS AND MODULATE
MUCOSAL INFLAMMATION. J.V. Weinstock.
9:00–11:00 SYMPOSIUM 8: MALARIA VECTORS, Regency 4.
Presiding:
F. Hernández-Hernández, CINVESTAV, México DF, México
G. Dimopoulos, Johns Hopkins University, Baltimore MD, USA
Time
Paper
No.
9:00
162
THE MOSQUITO’S ANTI-PLASMODIUM IMMUNE DEFENSE. G. Dimopoulos.
9:30
163
VECTOR-PLASMODIUM INTERACTIONS: PLASMODIUM VIVAX DEVELOPMENT IN THE MAIN MALARIA VECTORS IN MÉXICO. M.H. Rodríguez*, L.
González-Cerón, M. Rodríguez, J.A. Nettel-Cruz and J.E. Hernández-Avila.
24
10:00
164
INNATE IMMUNITY IN MOSQUITO VECTORS: CELLS, MELANIN AND
IMMUNE PEPTIDES. B.M. Christensen.
10:30
165
SUITABILITY ENVIRONMENTAL MODEL FOR THE GEOGRAPHIC DISTRIBUTION OF MALARIA VECTOR MOSQUITOES IN MÉXICO. J.E. HernándezAvila*, M.H. Rodríguez and R. Santos.
9:00–11:00 SYMPOSIUM 9: WATER-BORNE PARASITES, Chichén Itzá 1-2.
Presiding:
M. Shibayama, CINVESTAV, México DF, México
M.L. Steinauer, The University of New Mexico, Albuquerque NM, USA
Time
Paper
No.
9:00
166
MECHANISM OF VIRULENCE OF ENTAMOEBA HISTOLYTICA. R. PérezTamayo*, A. Olivos, E. Ramos, M. Nequiz, M. El Hafidi, A. Saralegui, E. Tello,
R. López and I. Montfort.
9:30
167
THE CRYPTOSPORIDIUM VOLUNTEER STUDY: BRIDGES OVER
TROUBLED WATERS. C.L. Chappell*, P.C. Okhuysen and C. White.
10:00
168
WATER-BORNE FREE-LIVING AMEBAE AS AGENTS OF CNS INFECTIONS.
F.M. Marciano-Cabral* and G.A. Cabral.
10:30
169
DIFFERENTIATION OF GIARDIA LAMBLIA: NEW STRUCTURAL INSIGHTS.
A. Martínez-Palomo* and B. Chávez-Munguía.
11:00–11:30 COFFEE BREAK, Preconvene Area.
11:30–12:30 PLENARY SESSION 2, Regency 2.
Presiding:
S. Brant, The University of New Mexico, Albuquerque NM, USA
P. Schantz, NCZVED, CDC, Atlanta GA, USA
Time
Paper
No.
11:30
170
UNIQUE PARASITIC SPECIALISATIONS ACROSS THE MÉXICO–U.S.A.
BORDER. R.C. Tinsley.
12:00
171
HELMINTH PARASITES OF FRESHWATER FISHES IN MÉXICO: UNCOVERING PATTERNS OF SPECIES RICHNESS. G. Pérez-Ponce De León.
11:30–12:45 ECOLOGY-2, Regency 3.
Presiding:
H. Eure, Wake Forest University, Winston-Salem NC, USA
D. González-Solís, Colegio de la Frontera Sur, Chetumal, Quintana Roo, México
25
Time
Paper
No.
11:30
172
SOCIAL RANK AND PARASITISM IN JAPANESE MACAQUES. A.D.
Hernández* and M.A. Huffman.
11:45
173
EPIDEMIOLOGY AND CHRONOBIOLOGY OF SCHISTOSOMES FROM LAKE
VICTORIA, KENYA. M.L. Steinauer*, I.N. Mwangi, J.M. Kinuthia, G.M. Maina,
G.M. Mkoji and E.S. Loker.
12:00
174
FOOD WEBS AND SEASONAL DYNAMICS OF AN AMPHIBIAN PARASITE
COMMUNITY: DO BOTTOM-UP EFFECTS DRIVE INFECTION? T.R. Raffel*,
R.S. Huang, J.M. Kiesecker and P.J. Hudson.
12:15
175
ESCAPING THE POOP COCOON: ARE THERE BEHAVIORAL ADAPTATIONS
OF TOAD TAPEWORMS FOR TRANSMISSION? M.G. Bolek* and J. Janovy, Jr.
12:30
176
PARASITES OF THE FIDDLER CRAB UCA THAYERI IN CELESTÚN, YUCATÁN, MÉXICO. N. Argáez-García*, L. Aguirre-Macedo and S. GuillénHernández.
SATURDAY AFTERNOON, JUNE 23
12:30–2:30 POSTER SESSION-2 AND LUNCH, Regency 1.
Authors stand by their posters.
CHEMO
THERAPY
ANCE
CHEMOTHERAPY
THERAPY,, DRUG RESIST
RESISTANCE
177
ANALYSIS OF AN ABCG GENE IN DRUG SENSITIVE AND RESISTANT LINES OF
PLASMODIUM YOELII. I. Ferrer-Rodríguez*, B. González, J.A. García, G. González, J.
Vega and A.E. Serrano.
178
DETECTION OF NEOSPORA CANINUM ANTIBODIES IN MILK IN KOREA. S.
Kang*, Y. Cho, E.H. Lee, S. Jung and Y. Jin.
179
IN VITRO EFFICACY OF NITAZOXANIDE AGAINST TOXOPLASMA GONDII. M.
Galvan-Ramírez*, J.A. Galvan Vega, L.R. Rodríguez Pérez, M.A. Ramirez Herrera and
M.L. Mendoza-Magaña.
180
EFFECT OF CURCUMIN ON G. LAMBLIA GROWTH, VIABILITY, ADHESION CAPACITY, MORPHOLOGY, APOPTOTIC-LIKE CHANGES AND ION CURRENTS. M.A.
Ramirez-Herrera*, M.L. Mendoza-Magaña, R.A. Navarro-Polanco, J.A. SánchezChapula, R. Cortés-Zárate, J. Lara-Chávez and L. Pérez-Arriaga.
181
DESIGN AND SYNTHESIS OF THE BENZYL ESTER OF N-PROPYL OXAMATE AS A
POSSIBLE TRYPANOCIDAL PRO-DRUG. C. Aguirre-Alvarado *, L. Rodríguez-Páez,
M.I. Baeza-Ramírez, B. Nogueda-Torres and C. Wong-Ramírez.
182
DETERMINATION OF ANTHELMINTIC DRUG SUSCEPTIBILITIES OF TAENIA
CRASSICEPS BY A FLUORESCENT LABEL ASSAY. D. Garcia-Vilchis*, J.R. AmbrosioHernández, O.A. Reynoso-Ducoing, R. Castillo, A. Hernández, F. Hernández and L.
Yépez-Mulia.
26
183
APPARENT EMERGENCE OF PRAZIQUANTEL RESISTANCE IN A KENYAN ISOLATE OF SCHISTOSOMA MANSONI. S.D. Melman*, M.L. Steinauer, E.S. Hatton,
G.M. Mkoji, A. Aragon, C. Cunningham and E.S. Loker.
184
GENE EXPRESSION ANALYSIS OF HEAT SHOCKED SCHISTOSOMA MANSONI
AND ITS APPLICATION IN THE DEVELOPMENT OF ASSAYS TO MONITOR
PRAZIQUANTEL RESISTANCE. R. Imani*, A. Aragon and C. Cunningham.
185
STUDY OF THE REPRODUCTIVE CAPACITY OF TRICHINELLA SPIRALIS RECOVERED FROM EXPERIMENTALLY INFECTED MICE AFTER UNDER-DOSE TREATMENT WITH ALBENDAZOLE OR MEBENDAZOLE. J.L.A. de la Rosa, N. Álvarez and
A. Gómez-Priego*.
186
COMPARISON OF MOXIDECTIN + PRAZIQUANTEL, IVERMECTIN AND
FEBANTEL + METRIPHONATE EFFICACY AGAINST HORSE PARASITES IN THREE
MEXICAN REGIONS. M.C. Guerrero Molina*, E. Romero Callejas, P. Ochoa Galvan
and Y. Alcala Canto.
187
PREVALENCE OF SHEEP FARMS WITH ANTHELMINTIC RESISTANT NEMATODES
IN TWO STATES OF TROPICAL MÉXICO. J.F. Torres-Acosta*, C. López-Cevantes,
A.M. Ortíz-De-Montellano-Nolasco, R. Camara-Sarmiento, J. Canto-Dorantes, C.
Martínez-Ortíz-de-Montellano, J. Rodríguez, H.L. Canul-Ku, F. Tirado-Munoz, A.J.
Aguilar-Caballero and B. Roberts.
188
USE OF REPETITIVE DOSES OF A COMBINATION OF AN ALBENDAZOLE–
IVERMECTIN ASSOCIATION AGAINST TOXOCARA CANIS ENCYSTED LARVAE IN
WHITE MICE. J.P. Martínez-Labat*, C. Fernández-González and C. Ortíz-Rivera.
189
ANTHELMINTIC EFFECT OF ALBENDAZOLE IN DIFFERENT DOSES AGAINST
TOXOCARA CANIS ENCYSTED LARVAE IN WHITE MICE. J.P. Martínez-Labat* and E.
Jaramillo-Alcántara.
190
ANTHELMINTICS AND INTESTINAL OBSTRUCTION DUE TO ASCARIS LUMBRICOIDES. O. Vázquez-Tsuji*, M.A. Yamasaki-Nakashimada, T. Campos-Rivera, P.
Gutiérrez-Castrellon and R.H. Medina-Campos.
ECOL
OGY
ECOLOGY
191
PRESENCE OF NAEGLERIA FOWLERI IN A THERMAL SPA WITH A GEYSER IN
MÉXICO. E.M. Gallegos-Neyra*, A. Calderón-Vega, K. Rangel-Ruiz and P. CastilloNava.
192
HETEROPHYID TREMATODES ARE CORRELATED WITH EMERGENT OCULAR
PATHOLOGIES IN CICHLID FISHES FROM NICARAGUA. M.I. Jiménez-García*, J.K.
McCrary and V.M. Vidal-Martínez.
193
ENTOMOLOGICAL ASSESSEMENT OF CHAGAS DISEASE VECTORS IN SOUTHERN BELIZE. R. Polonio, M.J. Ramirez-Sierra and E. Dumonteil*.
194
SURVIVORSHIP OF CYATHOCOTYLE BUSHIENSIS AND ITS SNAIL HOST FOLLOWING EXPERIMENTAL DESICCATION. E.M. Koppel* and R.E. Sorensen.
27
195
PARASITE CHARACTERIZATION IN JUVENILE AND FRY TILAPIAS CULTURED IN
VERACRUZ, MÉXICO. M.I. Jiménez-García*, M.D. Castañeda-Chávez, S.B. CruzOrdóñez and M.D. Pérez-Fosado.
196
SELF-MEDICATION AS AN ANTI-PARASITIC ADAPTATION IN JAPANESE
MACAQUES. C.J. Dagg.
197
IN VITRO ACTIVITY OF CALCIUM HYDROXIDE AGAINST GIARDIA LAMBLIA
CYSTS. B. Nogueda-Torres*, R.M. Sánchez-Manzano, B. Chávez-Munguía, A. MárquezNavarro and A. Camacho-Vera.
198
SEASONAL VARIATION OF THE METACERCARIA PARVATREMA POLYMESODA ON
THE MARINE CLAM, POLYMESODA MARITIMA, IN A MANGROVE SYSTEM OF
PROGRESO, NORTHERN YUCATÁN PENINSULA. K.P. Rodríguez Medina* and S.
Guillén-Hernández.
199
HELMINTH COMMUNITIES OF THE “LEOPARD FROG” RANA BROWNORUM
SANDERS, 1973 (ANURA: RANIDAE) FROM YUCATÁN, MÉXICO. C.A. YañezArenas* and S. Guillen-Hernández.
200
ENDOHELMINTHS OF THE THREESPINE STICKLEBACK, GASTEROSTEUS
ACULEATUS, FROM TWO LOCATIONS IN WESTERN NORTH AMERICA. A.
Choudhury*, J. Cheng, J. Tracey, M. Kolipinski and S. Ghosh.
201
SUSCEPTIBILITY OF FRY TILAPIAS (OREOCHROMIS NILOTICUS, STIRLING AND
ROCKY MOUNTAIN, AND THE HYBRID PARGO CERESO) TO BE INFECTED BY
ECTOPARASITES. S.B. Cruz-Ordóñez*, M.I. Jiménez-García, M.D. Castañeda-Chávez
and C. Mato-López.
202
CENTRAL AMERICA IS AN AREA OF ENDEMISM FOR HELMINTH PARASITES OF
FRESHWATER FISH. G. Salgado-Maldonado.
GENETICS, MOLECULAR BIOL
OGY
-1
BIOLOGY
OGY-1
203
ISOLATION AND CHARACTERIZATION OF LOCUS EHCPADH IN A PHAGOCYTOSIS-DEFICIENT MUTANT OF ENTAMOEBA HISTOLYTICA. R. Guzmán-Medrano*,
B.A. Castillo-Juarez, A. Salas-Casas, E. Orozco and M.A. Rodríguez.
204
ALTERATIONS IN RABB PROTEIN IN A PHAGOCYTOSIS-DEFICIENT MUTANT OF
ENTAMOEBA HISTOLYTICA AND IN ENTAMOEBA DISPAR. R. Guzmán-Medrano*,
B.A. Castillo-Juarez, R.M. Garcia-Pérez, A. Salas-Casas, E. Orozco and M.A. Rodríguez.
205
MOLECULAR CHARACTERIZATION OF THE SUBUNITS C160, C128, C82 AND C37
OF LEISHMANIA MAJOR RNA POLYMERASE III. L.E. Florencio-Martínez*, C.M.
Gomez-Hurtado, I.I. Sánchez-Santamaria, N.E. Padilla-Mejia and S. Martínez-Calvillo.
206
FUNCTIONAL ANALYSIS OF THE POLYADENYLATION SIGNALS IN TRICHOMONAS VAGINALIS. V. Fuentes-Morales*, M.G. Barrera-Andrade, L. López-Griego, R.
Hernández-Fernández and M.I. López-Villaseñor.
207
INSIGHTS IN DNA REPAIR AND HOMOLOGOUS RECOMBINATION IN ENTAMOEBA HISTOLYTICA: CHARACTERIZATION OF THE EHRAD51 RECOMBINASE. M.
López-Casamichana, C. López-Camarillo*, L.A. Marchat and E. Orozco.
28
208
ENTAMOEBA HISTOLYTICA DEAD-BOX RNA HELICASES FAMILY AND CHARACTERIZATION OF EHDEAD1, A CONSERVED RNA HELICASE WITH ATPASE AND
ATP-DEPENDENT RNA UNWINDING ACTIVITIES. C. López-Camarillo*, M. García
Hernández, L.A. Marchat, J.P. Luna-Arias and E. Orozco.
209
IDENTIFICATION OF PEPTIDE SEQUENCES RELATED TO APICOMPLEXAN
PROTEINS FROM SARCOCYSTIS NEURONA. J.W. Camp*, K. Kowalski and S.
Dangoudoubiyam.
210
DIFFERENTIAL GENE EXPRESSION PROFILES IN TAENIA SOLIUM CYSTICERCI
OBTAINED FROM DIFFERENT ANATOMICAL REGIONS OF INFECTED PIGS. A.
González, E.L. Sciutto*, R.J. Bobes, I. Estrada and G. Fragoso.
211
CLONING, EXPRESSION AND PURIFICATION OF EHADH243, A POLYPEPTIDE
INVOLVED IN ENTAMOEBA HISTOLYTICA VIRULENCE. S. Castellanos-Castro*, C.
Bañuelos, M. Martínez, C. Martínez-López and E. Orozco.
212
ASSOCIATION OF NRAMP1 GENE AND TNF- PROMOTER POLYMORPHISMS IN
LEISHMANIASIS. A. Ortíz-Flores, G. de la Rosa, S. Chavez-López, J. Pastor-Santiago,
C. Guzmán-Bracho, V. Martínez-Vilchis and A. Olivo-Diaz*.
213
THE EXPRESSION OF THE TRICHOMONAS VAGINALIS TVCP12 CYSTEINE PROTEINASE IS REGULATED BY THE IRE/IRP SYSTEM. C.D. León-Sicairos*, A.L.
Gutiérrez-Escolano and R. Arroyo.
214
IDENTIFICATION OF THE CYSTEINE PROTEINASE TVCP4 OF TRICHOMONAS
VAGINALIS. E. Solano-González*, L. Ávila-González, J. Ortega-López and R. Arroyo.
215
IRP-LIKE PROTEINS IN TRICHOMONAS VAGINALIS. J.C. Torres-Romero* and R.
Arroyo.
216
THE PYRUVATE FERREDOXIN OXIDO-REDUCTASE A (PFOR A) IS LOCATED ON
THE SURFACE OF T. VAGINALIS GROWN IN HIGH IRON CONDITIONS. P. MezaCervantez*, M.E. Alvarez-Sánchez and R. Arroyo.
217
THE LEGUMAIN-LIKE TVLEGU-1 CYSTEINE PROTEINASE IS ANCHORED BY
GLYCOSYLPHOSPHATIDYLINOSITOL ON THE SURFACE OF TRICHOMONAS
VAGINALIS. F.J. Rendón-Gandarilla*, N.A. Rodríguez-Cabrera, J. Ortega-López and R.
Arroyo.
218
CIRCUMSPOROZOITE GENE POLYMORPHISM AMONG PLASMODIUM VIVAX
VK210 AND VK247 PARASITE PHENOTYPES ISOLATED FROM SOUTHERN
MÉXICO. L. González-Ceron, C. Montero-Solís* and F. Santilla-Valenzuela.
219
STRUCTURAL AND FUNCTIONAL CHARACTERIZATION OF THE URE1-BINDING
PROTEIN OF ENTAMOEBA HISTOLYTICA. M. Calixto-Gàlvez*, M. Romero-Díaz and
M.A. Rodríguez-Rodríguez.
220
IDENTIFICATION AND FUNCTIONAL CHARACTERIZATION OF THE ACTIVATOR
REGION OF THE EHRABB GENE PROMOTER OF ENTAMOEBA HISTOLYTICA. M.
Romero-Díaz*, C. Gómez, E. Orozco and M.A. Rodríguez.
221
MOLECULAR CONFIRMATION OF TAENIA SOLIUM ISOLATES FROM SOUTHERN
MÉXICO. G.R. Hernández-Cisneros*, R.D. Rodríguez-Canul, J.A. Pérez-Vega, H.
Yamasaki, F. Cen-Aguilar, J.C. Allan and P.S. Craig.
29
222
GENOTYPING GIARDIA INTESTINALIS IN MÉXICO: WHERE IS GENOTYPE B? F.
Vargas-Puerto*, R. Moo-Puc, V. Suárez-Solís, R. Reyes and R. Cedillo-Rivera.
223
INITIAL CHARACTERIZATION OF THE PUTATIVE POLYADENYLATION AND
TRANSCRIPTIONAL FACTOR EHPC4 OF ENTAMOEBA HISTOLYTICA. O.N.
Hernández De La Cruz*, L.A. Marchat, E. Orozco and C. López-Camarillo.
224
IDENTIFICATION OF THE POLY (A) RIBONUCLEASES FAMILY IN ENTAMOEBA
HISTOLYTICA AND INITIAL CHARACTERIZATION OF THE EHCAF1 DEADENYLASE. I. López-Rosas*, B. Gallo, C. López-Camarillo, E. Orozco and L.A. Marchat.
225
POSITION EFFECTS AT TELOMERES THAT CONTROL VAR GENE REGULATION
IN PLASMODIUM FALCIPARUM. R. Hernández-Rivas and A. Scherf*.
226
IMMUNIZATION WITH TCSPA::TCHSP70ATP AND TCSPA::TCHSP70CHP RECOMBINANTE PROTEINS PARTIALLY PROTECT AGAINST ACUTE PHASE OF CHAGAS’
DISEASE IN THE MOUSE MODEL. B. Salgado-Jiménez*, L. Baylón Pacheco, P.
Talamás-Rohana and J.L. Rosales-Encina.
227
GENE TARGETING AND BIOCHEMICAL CHARACTERIZATION OF CLAN SB AND
SC SERINE PROTEASES IN LEISHMANIA SPP. R.K. Swenerton*, B.L. Kelly, M. Sajid
and J.H. McKerrow.
228
VARIATION OF ONCHOCERCA VOLVULUS MEXICAN ISOLATES. A. MonroyOstria*, A. Ramirez-Ramirez and S. González-Guzmán.
229
DETECTION OF TOXOPLASMA GONDII BY COPROPARASITOSCOPIC ELISA IN
BLOOD SERUM PCR AND IN FECES OF ARTIFICIALLY INOCULATED CATS. N.
Cárcamo-Aréchiga*, S.M. Gaxiola-Camacho and J.J. Portillo-Loera.
230
CRYPTOSPORIDIUM IN OYSTERS SOLD IN MÉXICO CITY’S POPULAR MARKETS
AND COMMERCIAL CENTRES. O. Vázquez-Tsuji*, T. Campos-Rivera, A. RondánZárate, M. Ponce-Macotela, M. Martínez-Gordillo, M. Gutiérrez-Quiróz and D.
Zaragoza-Alvarez.
HOST–P
ARASITE INTERACTIONS
HOST–PARASITE
231
TEMPORAL DYNAMICS OF PARASITIC MITE AGGREGATION (ACAROPHENAX
TRIBOLII) ON RED FLOUR BEETLE POPULATIONS (TRIBOLIUM CASTANEUM).
T.J. Dobrzeniecki* and J.E. López.
232
LOCAL ADAPTATION FOR VIRULENCE OF THE ECTOPARASITIC MITE ACAROPHENAX TRIBOLII ON RED FLOUR BEETLES (TRIBOLIUM CASTANEUM). K.L.
Kolar*, G.K. Dunleavy and J.E. López.
233
PREVALENCE AND TRANSOVARIAL TRANSMISSION OF TRYPANOSOMATID IN
THE INSECT HOST CYRTOMENUS BERGI FROESCHNER (HEMIPTERA: CYDNIDAE). A.M. Caicedo*, G. Gallego, G.A. Torres, J.E. Muñoz and J. Montoya-Lerma.
234
AMOEBIC LIVER ABSCESS REGENERATION AFTER TREATMENT WITH METRONIDAZOLE. M. Sánchez-Palomero*, R. Gaxiola-Centeno, V. Tsutsumi and M.
Shibayama.
30
235
PRESENCE OF GASTROINTESTINAL HELMINTHS IN THE ANTILLEAN MANATEE
(TRICHECHUS MANATUS MANATUS) FROM THE STATE OF TABASCO, MÉXICO. A.
Hernández-Olascoaga*, L.D. Olivera-Gomez and J.L. Dominguez-Alpizar.
236
CHARACTERIZATION OF VESICLES WITH FIBRILAR CONTENT PRESENT IN
ENTAMOEBA HISTOLYTICA TROPHOZOITES RECOVERED FROM EXPERIMENTAL LIVER ABSCESS. N. Segovia-Gamboa*, Y. Medina-Flores, L. Pérez-Castillo, A.
Angel, V. Hernández-Ramírez, B. Cháve-Munguía, A. Martínez-Palomo and P. TalamásRohana.
237
DETECTION OF SECRETORY AND CYTOSOLIC PHOSPHOLIPASE A2 IN MACROPHAGES STIMULATED WITH ENTAMOEBA HISTOLYTICA SOLUBLE PROTEINS.
B.E. Sánchez-Ramirez*, H. Chaparro-Reyes, M.D. González-Horta and P. TalamásRohana.
238
CHRONIC PSYCHOSOCIAL STRESS-INDUCED DOWN-REGULATION OF IMMUNITY: THE EFFECT OF ISOLATION IN A MURINE MODEL OF EXPERIMENTAL
CYSTICERCOSIS INFECTION. G. Fragoso, L. Mayagoitia, L. Pavon, E. Castillo, B.
Hernández, M. Mañon, E.L. Sciutto* and G. Rosas.
239
LIFE CYCLE OF TRIATOMA PALLIDIPENNIS (STALL,1872) AND OTHER ASPECTS
ABOUT ITS BIOLOGY. J. Tay*, J.T. Sánchez-Vega, L. Calderón-Romero, R. RomeroCabello, D. Ruiz-Sánchez and J.A. García-Tay.
240
RELATIONSHIP OF FREPS TO ACQUIRED RESISTANCE IN THE SNAIL BIOMPHALARIA GLABRATA. B.A. Stout*, S. Zhang, C.M. Adema and E.S. Loker.
241
BOOPHILUS MICROPLUS TICK-TRANSMISSION OF TWO DIFFERENT MEXICAN
ANAPLASMA MARGINALE STRAINS. R. Pérez-Munoz*, N.N. Mora-Contreras, E.E.
Rojas-Ramirez, M.A. Garcia-Ortíz, J.F. Preciado-de-la-Torre, R. Hernández-Ortíz and
S.D. Rodríguez.
242
DIFFERENT ENDOCYTIC PATHWAYS FOR HUMAN HOLO-TRANSFERRIN AND
HOLO-LACTOFERRIN PROTEINS IN ENTAMOEBA HISTOLYTICA. M. Reyes-López*,
N. León-Sicairos, A. Canizalez-Roman and M. de la Garza.
243
CO-EXPRESSION OF THE TVLEGU-1 OF TRICHOMONAS VAGINALIS WITH CHAPERONES FAVORS ITS EXPRESSION IN A SOLUBLE FRACTION. R. Arroyo*, N.A.
Rodríguez-Cabrera, L. Brieba-De Castro and J. Ortega-López.
244
ANTI-TREMATODE PARASITE RESPONSES OF THE SNAIL BIOMPHALARIA GLABRATA: ARCHITECTURE OF FREP LOCI. C. Lun*, T.M. Madrid, B. Hanelt and C.M.
Adema.
245
PARASITOLOGIC AND ULTRASONOGRAPHIC STUDY IN DOGS AND SHEEP
FROM A COMMUNITY IN THE STATE OF MÉXICO. U.G. Rodríguez, P.J. MaravillaCampillo*, A. Gutiérrez, P. Mata, J.J. Martínez and Ana Flisser.
246
DERMATOPHAGOIDES SP. CLOSE TO D. FARINAE MITES IN COMMERCIAL HENS
THAT CAUSE DERMATITIS AND LOSS OF FEATHERS. M.T. Quintero-Martínez*,
I.G. Juárez-Vega, A. Eleno-Villa and E. Plascencia.
247
ACTIN CYTOSKELETON OF MDCK CELLS WAS MODIFIED BY TOXOPLASMA
GONDII. S. Muñiz-Hernández*, M. Mondragón, S. González and R. Mondragón.
31
248
PARASITOSIS IN CHAETOGNATHS IN THE NORTH OF THE MEXICAN CARIBBEAN SEA. H. Lozano-Cobo*, M. Gomez Del Prado-Rosas, J.N. Alvarez-Cadena and
A.R. Almaral-Mendivil.
249
INDUCTION AND CHARACTERIZATION OF THE CONOID EXTRUSION IN TOXOPLASMA GONDII TACHYZOITES. M. González-Del Carmen*, M. Mondragón, S.
González, I. Galván and R. Mondragón.
250
SURVIVAL OF MYCOBACTERIUM TUBERCULOSIS H37RV INSIDE ENTAMOEBA
HISTOLYTICA STRAIN HM1:IMSS. G.G. Sánchez-Cañas, F.J. Solís-Martínez, L.G.
Cordoba-Fierro, J. Carrazco-Palafox, B.E. Sánchez-Ramirez*, V. Nevarez-Moorillon and
B.E. Rivera-Chavira.
251
COMMUNITY HELMINTH PARASITES OF FRESHWATER FISHES OF BAJA CALIFORNIA SUR, MÉXICO. O. Méndez* and G. Salgado-Maldonado.
252
COMPARING IN VITRO EFFECTS OF ANTIBIOTICS, ANTHELMINTICS AND ANTIFUNGAL AGENTS ON THE REMOVAL OF MICROSPORIDIA, HETEROSPORIS
ANGUILLARUM, AND SURVIVAL OF FISH CELLS. S.R. Monaghan*, C. Lo, N.C. Bols
and L.E. Lee.
253
CLINICAL STUDY OF DOGS NATURALLY INFECTED WITH TRYPANOSOMA CRUZI
IN MERIDA, YUCATÁN, MÉXICO. J.V. Cruz-Chan*, M. Bolio-González, R. ColínFlores, M.J. Ramirez-Sierra and E. Dumonteil.
254
COMPARATIVE STUDY OF MUSCULAR HISTOTROPISM OF FIVE MEXICAN TRYPANOSOMA CRUZI STRAINS. O.R. Dobrovinskaya*, V.G. Melnikov, F. EspinozaGómez, O. Newton-Sánchez, F. Guzmán-Rodríguez, F. Fierro-Velasco, B. Espinoza and I.
Martínez.
255
EFFECTS OF TAENIA CRASSICEPS INFECTION ON THE ESTRUS CYCLE AND
SEXUAL BEHAVIOR PATTERN IN FEMALE MICE. M. Arteaga-Silva*, M. RodríguezDorantes and J. Morales-Montor.
256
SEXUAL DIMORPHISM OF CYTOKINES AND SEX STEROID RECEPTORS DURING
MURINE CYSTICERCOSIS. M.A. De León-Nava*, J.A. Vargas-Villavicencio, C. Larralde
and J. Morales-Montor.
257
PROGESTERONE RECEPTOR EXPRESSION IN THE CENTRAL NERVOUS SYSTEM
OF FEMINIZED INFECTED MALE MICE. M. Rodríguez-Dorantes*, M.A. CerbónCervantes and J. Morales-Montor.
258
PREVALENCE OF PERKINSUS MARINUS OF THE EASTERN OYSTER CRASSOSTREA
VIRGINICA, SW GULF OF MÉXICO: ENVIRONMENTAL, PHYSIOLOGICAL AND
IMMUNOLOGICAL FACTORS ASSOCIATED. M. Gullian-Klanian*, L. Aguirre-Macedo
and R.D. Rodríguez-Canul.
2:30–3:00
COFFEE BREAK, Preconvene Area.
3:00–4:30
REMOVAL OF POSTERS, Regency 1.
Authors of Poster Session-2 remove their posters (177–258).
32
3:00–6:00
IMMUNOLOGY-1, Regency 2.
Presiding:
C.A. Hall, Berry College, Mount Berry GA, USA
M. Bebsevic, University of Alberta, Edmonton, Alberta, Canada
Time
Paper
No.
3:00
259
PRELIMINARY EVIDENCE AND PATHOGENIC EFFECTS OF PANULIRUS
ARGUS VIRUS 1 (PAV1) IN THE CARIBBEAN SPINY LOBSTER FROM THE
REEF LAGOON, PUERTO MORELOS, MÉXICO. J.P. Huchin-Mian*, R.
Rodríguez-Canul, E. Lozano-Álvarez, P. Briones-Fourzán, C. Pascual-Jiménez and
E. Arias-Bañuelos.
3:15
260
COCCIDIOSIS CONTROL IN POULTRY AS A MODEL FOR THE CONTROL
OF MALARIA. E.H. Lee.
3:30
261
IMMUNOMODULATORY ROLE OF PYRIMETHAMINE IN MALARIA-INFECTED MICE. M. Legorreta-Herrera* and A. Ramos-Avila.
3:45
262
TOXOPLASMA GONDII-SPECIFIC CLASSES AND SUBCLASSES IN MOTHER/
NEWBORN PAIRS. I. Cañedo-Solares*, M. Galván-Ramírez, H. Luna-Pastén, L.
Rodríguez-Pérez, L.B. Ortíz-Alegría, C.P. Rico-Torres, M. Vela-Amieva, M. PérezAndrade and D. Correa.
4:00
263
TOXOPLASMA GONDII INFECTION IN MOTHERS INDUCES CHANGES IN
LYMPHOID ORGANS OF NEONATAL MICE. M.A. Cabañas-Cortes*, E.A.
García-Latorre, E. Reyes-Maldonado and L.A. Jiménez-Zamudio.
4:15
264
EVALUATION OF THE IMMUNOGENICITY OF LYT1 RECOMBINANT OF
TRYPANOSOMA CRUZI. C.E. Angulo-Rojo*, L. Cedillo-Barron, J. CabreraCordero and R.G. Manning-Cela.
4:30
265
THE MULTIEPITOPE ANTICYSTICERCOSIS VACCINE FROM LABORATORY
TO THE FIELD: NOVEL DELIVERY SYSTEMS AND ALTERNATIVE ROUTES
FOR VACCINE ADMINISTRATION. E.L. Sciutto*, M. Hernández, J. Morales,
G. Rosas, A. Toledo, M. Huerta, A. Diaz, J. Cervantes, J.J. Martínez, A. Aluja, G.
Gevorkian, G. Acero, L. Herrera-Estrella, J.L. Cabrera-Ponce, F. López-Casillas,
A. Blancas, K. Manoutcharian, G. Fragoso and C. Larralde.
4:45
266
NEUROCYSTICERCOSIS: IMMUNOLOGICAL PREDICTIVE MARKERS FOR
TREATMENT PROGNOSIS. D. San Juan, B.I. Saenz, A. Chavarria, C. Márquez,
G. Fragoso, E.L. Sciutto and A. Fleury*.
5:00
267
EXPLORING DIFFERENT SYSTEMIC AND ORAL ANTIGEN DELIVERY
SYSTEMS TO IMPROVE THE ANTI-CYSTICERCOSIS VACCINE. J. Cervantes,
M. Hernández, K. Manoutcharian, G. Gevorkian, G. Acero, J.L. Cabrera-Ponce,
L. Herrera-Estrella, N. Ainciart, F.A. Goldbaum, G. Fragoso and E.L. Sciutto*.
5:15
268
THE USE OF TAENIA SOLIUM SYNTHETIC PEPTIDES DERIVED FROM A 26
KDA ANTIGENIC REGION TO ASSESS SERODIAGNOSIS OF PORCINE
CYSTICERCOSIS. J.A. Pérez-Vega *, R.D. Rodríguez-Canul, F. Cen-Aguilar and
P.S. Craig.
33
5:30
269
EXPRESSION OF GROUP V SECRETORY PLA2 IN MACROPHAGES DURING
AMOEBIC LIVER ABSCESS FORMATION. B.E. Sánchez-Ramirez*, M. MoguelTorres, E. Ramos-Martínez and P. Talamás-Rohana.
5:45
270
INDUCTION OF AMOEBIC LIVER ABSCESS IN A IL-6 KO C57BL/6 MICE. M.
Esquivel Velázquez*, E. Estrada-Villaseñor, J. Morales, E. Ramos-Martínez, M.
Nequiz- Avendaño and P. Ostoa-Saloma.
3:00–6:00
ECOLOGY-3, Regency 3.
Presiding:
K. Lafferty, University of California, Santa Barbara CA, USA
C.P. Goater, University of Lethbridge, Lethbridge, Alberta, Canada
Time
Paper
No.
3:00
271
MALARIA PARASITES (PLASMODIUM) IN INVASIVE BROWN ANOLES
(ANOLIS SAGREI) IN FLORIDA. S.L. Perkins*, A. Rothschild and E. Waltari.
3:15
272
PHENOTYPIC TRADE-OFFS BETWEEN NUMBER AND SIZE OF EGGS: ARE
PARASITES DIFFERENT FROM FREE-LIVING ORGANISMS? V. Herreras, F.E.
Montero, D.J. Marcogliese, J.A. Raga and J.A. Balbuena*.
3:30
273
DISENTANGLING HOST COLONIZATION AND HYBRIDIZATION PATTERNS IN HUMAN AND PIG ASCARIS: IS IT POSSIBLE? C.D. Criscione*, J.D.
Anderson, D. Sudimack, W. Peng, M.E. Romero-Abal, J. Subedi, D.R. Rai, R.P.
Upadhayay, B. Jha, S. Williams-Blangero and T.J. Anderson.
3:45
274
GLOBAL WARMING AND DISEASE: EFFECTS ON TREMATODE CERCARIAE. B.L. Fredensborg*, R. Sandoval, K.D. Lafferty and A.M. Kuris.
4:00
275
DISINFECTANT ACTIVITY OF THREE COMMERCIAL FORMULATIONS
AND MICRONIZED CALCIUM HYDROXIDE AGAINST BLASTOCYSTIS
HOMINIS. G. Ibáñez-Cervantes*, R.M. Sánchez-Manzano, A. Márquez-Navarro
and B. Nogueda-Torres.
4:15
276
EXAMINATION OF PREZYGOTIC MATING BARRIERS BETWEEN SCHISTOSOMA MANSONI AND SCHISTOSOMA RODHAINI. E.S. Hatton*, M.L.
Steinauer and E.S. Loker.
4:30
277
DISTRIBUTION AND ABUNDANCE OF PARASITES OF KELLETIA KELLETII,
A MARINE WHELK WITH A RECENT RANGE EXPANSION. J. Lorda*, J.V.
Hopper, C. White, S. Koch and A.M. Kuris.
4:45
278
INTEGRATING PARASITE COMMUNITY ANALYSIS WITH FISHERIES
OCEANOGRAPHY: A MORE COMPREHENSIVE LOOK AT THE OCEAN
ECOLOGY OF JUVENILE PACIFIC SALMONIDS. K.C. Jacobson*, R.E.
Baldwin, D.C. Reese and D.J. Teel.
5:00
279
A SINGLE-SEXED GORDIID (NEMATOMORPHA: GORDIIDA) SPECIES
FROM KENYA: ITS IMPLICATIONS FOR THE GENERAL BIOLOGY OF THE
PHYLUM AND FOR THE NEED FOR A GLOBAL GORDIID SURVEY. B.
Hanelt.
34
5:15
280
REMOVAL OF THE INFECTIVE STAGES OF GIARDIA AND CRYPTOSPORIDIUM SPECIES FROM ANIMAL WASTE STREAMS USING THERMOPHILIC
ANAEROBIC DIGESTION. T.R. Ruhnke* and V. Carrasco.
5:30
281
NEMATODE AND TREMATODE LIFE CYCLE STRATEGIES IN STRUCTURING AMPHIBIAN HELMINTH COMMUNITIES. M.G. Bolek* and J. Janovy, Jr.
5:45
282
LARVICIDAL POTENTIALS OF EUCALYPTUS CAMALDULENSIS (SCHLECT)
AND EUCALYPTUS CITRIODORA (HOOK) ON CULEX QUINQUEFASCIATUS
(SAY) LARVAE. H.S. Idris* and S.B. Lawal.
3:00–5:45
ASP STUDENT PAPER COMPETITION-5, Regency 4.
Presiding:
V.A. Conners, University of South Carolina Upstate, Spartanburg SC, USA
I. Rodríguez-Vivas, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
Time
Paper
No.
3:00
283† SCHISTOSOME GENETIC DIVERSITY AND STRUCTURING IN A BRAZILIAN VILLAGE. E.A. Thiele*, R.E. Sorensen and D.J. Minchella.
3:15
284† MOLECULAR CHARACTERIZATION AND EVIDENCE OF GENETIC EXCHANGE IN U.S. ISOLATES OF TRYPANOSOMA CRUZI. D.M. Roellig*, A.W.
Fujita, M.Y. Savage, E.L. Brown and M.J. Yabsley.
3:30
285† CLONAL DIVERSITY OF THE MALARIA PARASITE, PLASMODIUM MEXICANUM: ALTERATIONS IN LIFE HISTORY TRAITS, VIRULENCE AND
TRANSMISSION. A.M. Vardo* and J.J. Schall.
3:45
286† EVALUATING WHOLE GENOME AMPLIFICATION FOR SMALL PARASITES:
TYPING HUNDREDS OF MICROSATELLITE MARKERS FROM SINGLE
MIRACIDIA OF SCHISTOSOMA MANSONI. C.L. Valentim*, P.T. Loverde, T.J.
Anderson and C.D. Criscione.
4:00
287† MODELING OF A POTENTIALLY UNIQUE SYLVATIC CYCLE FOR TRYPANOSOMA CRUZI IN THE SOUTHEASTERN UNITED STATES. E.M. Pierce*, C.A.
Hall, C. Kribs-Zaleta, A.N. Wimsatt, J.B. Meers and K. Newcomb.
4:15
288† COMPONENTS OF HOST EPIDERMIS REDUCE INFECTIVITY OF TREMATODE CERCARIAE. C.T. James*, B.D. Wisenden and C.P. Goater.
4:30
289† DETECTION OF NOVEL LINEAGES OF MALARIA PARASITES IN AFRICAN
BATS. E. Stiner.
4:45
290† IMMUNIZATION OF GOLDFISH WITH RECOMBINANT PARASITE β-TUBULIN CONFERS PROTECTION AGAINST TRYPANOSOMA DANILEWSKYI
INFECTION. B.A. Katzenback*, D.A. Plouffe, G. Haddad and M. Belosevic.
5:00
291† HUMORAL ANTIBODY RESPONSE OF THE TILAPIA OREOCHROMIS
NILOTICUS AGAINST CICHLIDOGYRUS SPP. J.J. Sandoval-Gío*, R.D.
Rodríguez-Canul and V.M. Vidal-Martínez.
35
5:15
292† FIRST REPORT ON POPULATION STRUCTURE FOR THE LEISHMANIA
MAJOR VECTOR, PHLEBOTOMUS PAPATASI SANDFLY, USING MICROSATELLITE LOCI. O. Hamarsheh*, W. Presber and G. Schönian.
5:30
293† PROBIOTICS: IS THIS THE WAY OF THE FUTURE IN COCCIDIOSIS CONTROL? J.L. McPherson-Komorowski* and J.R. Barta.
3:00–5:00
GENETICS, MOLECULAR BIOLOGY-2 Chichén Itzá 1-2.
Presiding:
F.-L.E. Chu, Virginia Institute of Marine Science, Gloucester Point VA, USA
P. Talamás, CINVESTAV, México DF, México
Time
Paper
No.
3:00
294
RNA POLYMERASE III TRANSCRIPTION COMPLEX IN LEISHMANIA MAJOR. S. Martínez-Calvillo*, P.J. Myler, L.E. Florencio-Martínez, D.E. VelezRamirez, C. Flores-Pérez and E.E. Figueroa-Angulo.
3:15
295
MONOXENIC GROWTH OF ENTAMOEBA HISTOLYTICA WITH ESCHERICHIA COLI 055 MODULATES AMOEBIC VIRULENCE AND GENE EXPRESSION. C.L. Mendoza-Macías*, M.P. Barrios-Ceballos, L.P. Cárdenas-De La Peña,
F. Anaya-Velázquez and F. Padilla-Vaca.
3:30
296
BABESIA BOVIS MEROZOITES AND KINETES DIFFERENTIALLY EXPRESS
MSA-2C AND HSP-20. J. Mosqueda*, Y. Rivera, A. Falcon, J.A. Ramos, J.V.
Figueroa, J.A. Alvarez, J. Norimine and W.C. Brown.
3:45
297
ANCYLOSTOMA CANINUM DAF-16 BINDS TO A CONSERVED DAF-16
FAMILY MEMBER-BINDING ELEMENT. X. Gao and J.M. Hawdon*.
4:00
298
CHANGES IN EXPRESSION OF HEAT SHOCK RESPONSE GENES DURING
ANCYLOSTOMA CANINUM LARVAL ACTIVATION. A. Lorsong, X. Gao, L.
Jennelle, A. Delaney and J.M. Hawdon*.
4:15
299
BABESIA BIGEMINA GLYCOPROTEIN 45: IN SILICO COMPARATIVE ANALYSIS
OF A VACCINAL STRAIN AND FIELD ISOLATES FROM MÉXICO AND
ARGENTINA. J. Mosqueda*, L.A. Castro, A. Falcon, J.A. Ramos, D. Benitez, E.
Alcaraz, J.V. Figueroa and J.A. Alvarez.
4:30
300
SERIAL ANALYSIS OF GENE EXPRESSION (SAGE) IDENTIFIES STAGEASSOCIATED GENE TRANSCRIPTS DURING LARVAL SCHISTOSOMA MANSONI LARVAL DEVELOPMENT. A.S. Taft* and T.P. Yoshino.
4:45
301
MOLECULAR EVIDENCE OF PERKINSUS MARINUS IN THE EASTERN
OYSTER CRASSOSTREA VIRGINICA FROM THE GULF OF MÉXICO. J.P. EkHuchim*, R. Rodríguez-Canul, R. Varela-Valencia, V.M. Vidal-Martínez, R. SimáÁlvarez and L. Aguirre-Macedo.
3:00–5:15
CHEMOTHERAPY, DRUG RESISTANCE, Uxmal 1-2.
Presiding:
A.J. Aguilar-Caballero, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
T.G. Geary, McGill University, Ste. Anne de Bellevue, Quebec, Canada
36
Time
Paper
No.
3:00
302
ANTHELMINTIC EFFECTS OF TANNIN-RICH PLANTS ON PARASITIC
NEMATODES OF SMALL RUMINANTS: POSSIBLE MODES OF ACTION
AGAINST THE INFECTIVE THIRD-STAGE LARVAE. H. Hoste*, S. Brunet, I.
Fouraste, G. Vilarem, F.J. Jackson, M.A. Alonso-Díaz, and F.J. Torres-Acosta.
3:15
303
AN OVERVIEW OF PARASITOLOGICAL RESEARCH ON THE SPOTTED
ROSE SNAPPER, LUTJANUS GUTTATUS: IMPLICATIONS FOR AQUACULTURE IN MÉXICO. E.J. Fajer-Ávila*, F. García-Vargas, R.M. Medina-Guerrero
and M. Betancourt-Lozano.
3:30
304
NOVEL BENCIMIDAZOLE DERIVATES AGAINST TOXOCARA CANIS SECOND-STAGE LARVAE AND HYMENOLEPIS NANA. A. Márquez-Navarro*, J.P.
Martínez-Labat, B. Nogueda-Torres, M.A. Hernández-Campos, L. Yépez-Mulia,
R. Castillo-Bocanegra and F. Hernández-Luis.
3:45
305
NEW NITRODERIVATES AGAINST TRYPANOSOMA CRUZI TRYPOMASTIGOTES. J.C. Villalobos-Rocha*, B. Nogueda-Torres, A. Márquez-Navarro and E.
Cortés-Cortés.
4:00
306
ANTHELMINTIC ACTIVITY OF NINE NEW SYNTHETIC DERIVATIVES OF 4HIDROXIPHENIL ETHYL CARBAMATE CHEMICALS AGAINST HAEMONCHUS CONTORTUS: AN IN VITRO MODEL. J.P. Martínez-Labat*, E. AngelesAnguiano and N. Pererira-Zuluaga.
4:15
307
EFFECT OF DIFFERENT IVERMECTIN DOSAGES ON ENCYSTED LARVAE
OF TOXOCARA CANIS IN WHITE MICE. J.P. Martínez-Labat* and N. AcostaSevilla.
4:30
308
GIARDIAL CYSTEINE-CONTAINING PROTEINS AS POSSIBLE TARGETS OF
THIOALLYL COMPOUNDS FROM GARLIC. R. Argüello-García*, M. De La
Vega-Arnaud, I.J. Loredo-Rodríguez, A.M. Mejía-Corona, E. Melgarejo-Trejo,
E.A. Espinoza-Contreras, A. González-Robles, N. Pérez-Hernández and M.G.
Ortega-Pierres.
4:45
309
DIFFERENTIAL DRUG METABOLIZATION AND EXPRESSION OF AN
ANTIOXIDANT PEROXIREDOXIN BETWEEN ALBENDAZOLE-SENSITIVE
AND RESISTANT CLONES OF GIARDIA DUODENALIS. R. Argüello-García*,
M. Cruz-Soto, R. González-Trejo and M.G. Ortega-Pierres.
5:00
310
ANALYSIS OF THE CYTOTOXIC ACTIVITY OF RECOMBINANT SCORPINE
ON BACTERIA, MALARIA PARASITES AND DENGUE VIRUS. R. Carballar
Lejarazu*, M.H. Rodríguez López, L.D. Possani Postay, F.D. HernándezHernández, R. Hernández and H. Lanz Mendoza.
SATURDAY EVENING, JUNE 23
7:00–10:00 FOLKLORIC BALLET OF THE UNIVERSITY OF YUCATÁN,
Central Courtyard, Main Building of the University of Yucatán.
37
SUNDAY MORNING, JUNE 24
8:00–12:30
POSTER SESSION-3: SET UP, Regency 1.
Authors of posters numbered 341–419 set up their posters.
9:00–11:00 SYMPOSIUM 10: PALEOPARASITOLOGY, Regency 2.
Presiding:
K. Reinhard, University of Nebraska, Lincoln NE, USA
A. Araujo, Escola Nacional de Saude Publica, Fundação Oswaldo Cruz, Rio de Janeiro,
Brasil.
Time
Paper
No.
9:00
311
ANCIENT MIGRATIONS BASED ON PALEOPARASITOLOGY. A. Araujo*, L.F.
Ferreira, A. Iñiguez, D. Leles and K.J. Reinhard.
9:30
312
CHAGAS DISEASE: FROM THE PAST TO THE PRESENT. K. Dittmar*, K.J.
Reinhard, A. Fernandez, A. Adauto, M. Fink and A. Jansen.
10:00
313
PREHISTORIC PATHOECOLOGY OF ANCESTRAL PUEBLO AND ARCHAIC
PEOPLES. K.J. Reinhard.
10:30
314
HELMINTH PARASITES IN PALEOFECES FROM CUEVA DE LOS MUERTOS
CHIQUITOS, RIO ZAPE VALLEY, DURANGO, MÉXICO. F.A. Jiménez* and K.J.
Reinhard.
9:00–11:00 SYMPOSIUM 11: PARASITE PROBLEMS IN WILD, DOMESTIC OR
CULTURED HOSTS, Regency 3.
Presiding:
V.M. Vidal-Martínez, CINVESTAV-IPN, Mérida, Yucatán, México
V. León-Règagnon, UNAM, México DF, México
Time
Paper
No.
9:00
315
WHERE RODENT PESTS AND RESERVOIRS MEET: A GEOGRAPHICAL
ANALYSIS OF AGRICULTURE RISK AREAS FOR TRANSMISSION OF
CHAGAS DISEASE IN MÉXICO. V. Sánchez-Cordero*, J. Ramsey, C. Ibarra and
T. Peterson.
9:30
316
THE BIOMASS OF PARASITES AND THE ENERGETICS OF ECOSYSTEMS.
A.M. Kuris.
10:00
317
SPATIAL ANALYSIS OF BOOPHILUS MICROPLUS RESISTANCE TO ACARICIDES IN SOUTHEASTERN MÉXICO. A.L. Rivas* and R.I. Rodríguez-Vivas.
10:30
318
THE ALIEN HELMINTH PARASITES OF MEXICAN FRESHWATER FISH. G.
Salgado-Maldonado* and T. Scholz.
38
9:00–11:00 SYMPOSIUM 12: COCCIDIOSIS CONFERENCE, Chichén Itzá 1-2.
Presiding:
K. Miska and M. Jenkins, APDL, ARS, USDA, Beltsville MD, USA
Theme:
Eimeria Oocyst Vaccines: Different Approaches to Combating Avian Coccidiosis
Time
Paper
No.
9:00
319
COCCIDIOSIS VACCINATION IN COMBINATION WITH THE USE OF AN
IONOPHORE IN THE GROWER FEED IMPROVED PERFORMANCE WHEN
COMPARED TO A TRADITIONAL COCCIDIOSIS VACCINATION PROGRAM.
M. Quiroz*, J. Dibner, C. Knight, B. Sánchez and T. Cherry.
9:30
320
THE GEL SPRAY DELIVERY OF COCCIDIOSIS VACCINE. E.H. Lee*, A.
Sunnucks, S. Andress and T. Cosstick.
10:00
321
COCCIVAC–EIMERIA MAXIMA PROTECTED AGAINST FIELD ISOLATES.
S.H. Fitz-Coy.
10:30
322
BIOLOGIC AND MOLECULAR TOOLS IN THE USE OF LIVE OOCYST
VACCINES. M.C. Jenkins* and K.B. Miska.
9:00–11:00 SYMPOSIUM 13: ASP–SMP STUDENT SYMPOSIUM, Regency 4.
Presiding:
L.I. Terrazas, UNAM, México, México
G. Sandland, Purdue University, West Lafayette IN, USA
Theme:
International Parasitology
Time
Paper
No.
9:00
323
IRON REGULATION IN TRICHOMONAS VAGINALIS. R. Arroyo*, C.D. LeónSicairos, E. Solano-González, J.C. Torres-Romero and J. Ortega-López.
9:30
324
FIELD RESEARCH ON INTESTINAL PARASITES IN MALNOURISHED
CHILDREN—IS THIS TYPE OF PROJECT FOR YOU? M.E. Scott.
10:00
325
NEW TOOLS FOR THE CONTROL OF CHAGAS DISEASE AND LEISHMANIASIS. E. Dumonteil.
10:30
326
EFFECTS OF SELECTIVE LOGGING AND FOREST FRAGMENTATION ON
PRIMATE-PARASITE INTERACTIONS. T.R. Gillespie*, E.C. Greiner and C.A.
Chapman.
11:00–11:30 COFFEE BREAK, Preconvene Area.
11:30–12:30 PLENARY SESSION 3, Regency 2.
Presiding:
B. Papadopoulou, Laval University, Québec, Canada
D. Correa, Instituto Nacional de Pediatría, SSA, México DF, México
39
Time
Paper
No.
11:30
327
CAN THE COMMON BRAIN PARASITE, TOXOPLASMA GONDII, INFLUENCE
HUMAN CULTURE? K.D. Lafferty.
12:00
328
THE ROLE OF SEX STEROIDS IN THE HOST–PARASITE NEUROIMMUNOENDOCRINE NETWORK: CONSEQUENCES TO THE HOST AND THE
PARASITE. J. Morales-Montor.
11:30–12:30 HOST–PARASITE INTERACTIONS-2, Regency 3.
Presiding:
J. W. Camp, Purdue University, West Lafayette IN, USA
R. Arroyo, CINVESTAV-IPN, México DF, México
Time
Paper
No.
11:30
329
A GALECTIN FROM HEMOCYTES OF THE OYSTER (CRASSOSTREA VIRGINICA) IS A POTENTIAL RECEPTOR FOR THE PARASITE PERKINSUS MARINUS. G.R. Vasta* and S. Tasumi.
11:45
330
DEVELOPMENT OF CRYPTOSPORIDIUM PARVUM IN AVIAN EMBRYOS.
K.M. Woods, C. Norris and S.J. Upton*.
12:00
331
CHARACTERIZATION OF PLASMODIUM FALCIPARUM ERYTHROCYTEBINDING LIGAND EBL-1. G.D. Mayer*, L. Mendoza and L.H. Miller.
12:15
332
NEURON SPECIFIC ENOLASE (NSE) AND S-100B PROTEIN IN THE SERUM
OF TOXOPLASMA GONDII CONGENITALLY INFECTED CHILDREN. J.
Hernández-Islas*, M. Galván-Ramírez, D.N. Solís-Rios, I. Cañedo-Solares, H.
Luna-Pastén, E. Calderón-Segura, M. Vela-Amieva, M. Pérez-Andrade, P.
Gutiérrez-Calderón and D. Correa.
11:30–12:30 LIFE CYCLES, EPIDEMIOLOGY-1, Regency 4.
Presiding:
W. Kozek, University of Puerto Rico, San Juan PR, USA
P.M. Salazar, UNAM, México DF, México
Time
Paper
No.
11:30
333
TRYPANOSOMA CRUZI IN MESOMAMMALS FROM ARIZONA AND GEORGIA. M.J. Yabsley*, E.L. Brown, K.M. Wenning and D.M. Roellig.
11:45
334
MODELING OF A POTENTIALLY UNIQUE SYLVATIC CYCLE FOR TRYPANOSOMA CRUZI IN THE SOUTHEASTERN UNITED STATES. C.A. Hall*, C.
Kribs-Zaleta, E.M. Pierce, A.N. Wimsatt, J.B. Meers and K. Newcomb.
12:00
335
FIRST REPORT OF AUTOCHTHONOUS TRANSMISSION OF THE CHAGAS
PARASITE, TRYPANOSOMA CRUZI, IN LOUISIANA AND SIXTH IN UNITED
STATES. P.L. Dorn*, L. Perniciaro II, M.J. Yabsley, D.M. Roellig, G. Balsamo, J.
Diaz and D. Wesson.
40
12:15
336
SEROPREVALENCE OF ANTIBODIES AGAINST TRYPANOSOMA CRUZI IN
PREGNANT WOMEN IN MÉXICO. R. Gamboa-León*, N. Padilla-Raygoza, O.
Almendares, M. Cafferata, M. James, E. Dumonteil and P. Buekens.
11:30–12:30 TAXONOMY, SYSTEMATICS, PHYLOGENY-2, Chichén Itzá 1-2.
Presiding:
T. Platt, St. Mary’s College, Notre Dame IN, USA
J.A. Almeyda-Artigas, Universidad Autónoma Metropolitana, Xochimilco, México DF,
México
Time
Paper
No.
11:30
337
INTERRELATIONSHIPS AND HOST ASSOCIATIONS OF THE ONCHOBOTHRIID CESTODES OF CARCHARHINIFORM SHARKS. J.N. Caira*, K. Jensen,
A. Waeschenbach and T.J. Littlewood.
11:45
338
MORPHOLOGICAL AND MOLECULAR EVIDENCE FOR PATTERNS OF
DIVERSITY AND HOST SPECIFICITY OF RHINEBOTHRIUM (CESTODA:
TETRAPHYLLIDEA) FROM SOUTH AMERICAN FRESHWATER STINGRAYS.
F.B. Reyda* and F.L. Marques.
12:00
339
HOST PHYLOGENY AS AN EXPLANATION OF THE DIVERSIFICATION OF
TETRAPHYLLIDEANS IN NEOTROPICAL FRESHWATER STINGRAYS: A
CASE STUDY WITH RHINEBOTHROIDES. F.P. Marques*, N.M. Luchetti and
V.M. Bueno.
12:15
340
TAPEWORMS (CESTODA: PROTEOCEPHALIDEA) OF FIREWOOD CATFISH
SORUBIMICHTHYS PLANICEPS (SILURIFORMES: PIMELODIDAE) FROM
THE AMAZON RIVER: A SURVEY OF SPECIES AND KEY TO THEIR IDENTIFICATION. A. De Chambrier and T. Scholz*.
SUNDAY AFTERNOON, JUNE 24
12:30–2:30 POSTER SESSION-3 AND LUNCH, Regency 1.
Authors stand by their posters.
GENETICS, MOLECULAR BIOL
OGY
-2
BIOLOGY
OGY-2
341
EPIDEMIOLOGY TEST IN PREGNANT MOTHERS AND THEIR NEWBORNS WHO
LIVE IN ENDEMIC AND NON-ENDEMIC ZONES OF CHAGAS DISEASE. J.C.
Barrera-Ortíz*, L.V. Jiménez-Rojas, G. Campos-Valdez, R. Sánchez De La Luz, M.
Caballero-Garcia and E. Jiménez-Cardoso, Sr.
342
PRESENCE OF T. CRUZI IN PREGNANT WOMEN AND NEWBORNS IN ENDEMIC
REGIONS OF MÉXICO. G. Campos-Valdez*, J.C. Barrera-Ortíz, L.V. Jiménez-Rojas, R.
Sánchez de la Luz, M.L. Caballero-Garcia and E. Jiménez-Cardoso, Sr.
343
SEROPREVALENCE OF GNATHOSTOMOSIS IN GUERRERO, MÉXICO. M.L. Caballero-Garcia*, S. López-Silva and E. Jiménez-Cardoso, Sr.
41
344
GENETIC DIVERSITY OF TRYPANOSOMA CRUZI STRAINS ISOLATED FROM
MÉXICO. L.V. Jiménez-Rojas*, J.C. Barrera-Ortíz, G. Campos-Valdez, R. Sánchez De La
Luz and E. Jiménez-Cardoso, Sr.
345
EXPRESSION OF GLUCOSAMINE 6-PHOSPHATE ISOMERASE, UBIQUITINE AND
CYST WALL PROTEIN GENES DURING ENCYSTMENT OF GIARDIA INTESTINALIS
BY REAL-TIME PCR ASSAY. E. Jiménez-Cardoso, Sr.*, L. Eligio-Garcia, Jr., M.
Crisostomo-Vazquez, Jr. and A. Flores-Luna.
346
GENOTYPING OF GIARDIA INTESTINALIS ISOLATED FROM DOGS BY RESTRICTION OF β-GIARDIN GENE. L. Eligio-Garcia, Jr.*, E. Jiménez-Cardoso, Sr., A. CortesCampos, S.D. Cota-Guajardo and N. Carcamo-Aréchiga.
347
POLYMORPHISM OF THE β-GIARDIN GENE IN ALBENDAZOLE RESISTANT
STRAINS OF GIARDIA INTESTINALIS. L. Eligio-Garcia, Jr.*, E. Jiménez-Cardoso, Sr.,
A. Cortes-Campos and A. Flores-Luna.
348
POLYMORPHISM RIBOSOMAL PROTEIN L30 GENE IN ENTAMOEBA HISTOLYTICA
CDNA ISOLATED FROM LIVER ABSCESS IN HAMSTER AND MONOXENIC CULTURE. M. Crisostomo-Vazquez, Jr.*, L. Eligio-Garcia, Jr., V. Maravelez-Acosta III, J.
Hernández-Garcia and E. Jiménez-Cardoso, Sr.
349
GENETIC DIFFERENCE OF E. HISTOLYTICA BY SUBTRACTIVE HYBRIDIZATION.
M. Crisostomo-Vazquez, Jr.*, L. Eligio-Garcia, Jr., V. Maravelez-Acosta III, J.
Hernández-Garcia and E. Jiménez-Cardoso, Sr.
IMMUNOL
OGY
IMMUNOLOGY
350
EIMERIA FALCIFORMIS EFFECT ON T HELPER 2-ASSOCIATED EOSINOPHILIC
RESPONSES INDUCED BY NIPPOSTRONGYLUS BRASILIENSIS INFECTION. Z.A. AlDahwi* and L.F. Mayberry.
351
THYMUS ATROPHY IN BALB/C MICE INFECTED WITH PLASMODIUM CHABAUDI
CHABAUDI AS. G. Ortíz-Estrada, L.H. Fabila-Castillo and L.E. Sánchez-Torres*.
352
DEVELOPMENT AND EVALUATION OF AN HDP2 SEMINESTED-PCR FOR DETECTING TAENIA SOLIUM DNA IN HUMAN CEREBROSPINAL FLUID: A NEW
TOOL TO IDENTIFY SOLVED NEUROCYSTICERCOSIS? M. Hernández*, L.M.
González, A. Fleury, B. Saenz, M. Avila, R.M. Parkhouse, L. Harrison, E.L. Sciutto and
T. Garate.
353
CYTOKINES AND NITRIC OXIDE DURING AMOEBIC LIVER ABSCESS DEVELOPMENT IN IMMUNIZED HAMSTERS. J. Pacheco-Yepez, S. Galindo-Gomez*, V.
Tsutsumi and M. Shibayama.
354
IMPAIRED PRO-INFLAMMATORY CYTOKINE PRODUCTION AND TH1 BIASING
ABILITY OF DENDRITIC CELLS EXPOSED TO TAENIA ANTIGENS. L.I. TerrazasValdéz*, C.A. Terrazas, I. Rivera-Montoya and M. Rodríguez-Sosa.
355
REGULATORY T CELLS INDUCTION BY PARASITIC ANTIGENS. Y. Flores-García*,
L. Pérez-Castillo, L. Baylón Pacheco, A. Angel, J.L. Rosales-Encina and P. TalamásRohana.
42
356
HISTOLOGICAL AND IMMUNOHISTOCHEMICAL DETECTION OF LEISHMANIA
(L.) CHAGASI IN THE SKIN OF INFECTED DOGS. W.A. Starke-Buzetti*, N.G.
Queiroz, R.S. Viveiros, A.F. Noronha, Jr., R.Z. Machado and T.F. Oliveira.
357
EVALUATION OF THE EFFICACY OF A COMBINATION OF DNA VACCINES ENCODING TSA-1 AND TC24 ANTIGENS IN MICE INFECTED WITH TRYPANOSOMA
CRUZI. J.L. Tzec-Arjona*, P. López-López, W.G. Chale-Balboa, G. Sánchez-Burgos,
M.J. Ramirez-Sierra and E. Dumonteil.
358
EFFICACY OF A DNA VACCINE AGAINST LEISHMANIA MEXICANA IN GOLDEN
HAMSTERS. W.G. Chale-Balboa*, J.L. Tzec-Arjona, M. Mut-Martin, M.J. RamirezSierra, M.D. Garcia-Miss and E. Dumonteil.
359
DIFFERENCES AND SIMILARITIES IN HUMAN AND PORCINE NEUROCYSTICERCOSIS: NECROPSIES STUDIES. B.I. Saenz*, A. S. De Aluja, A. Escobar, G. Fragoso, R.
Pérez-Tamayo, F. Rosetti, E.L. Sciutto and A. Fleury.
360
PREVALENCE OF ANTI-L-220 ANTIBODIES IN INDIVIDUALS PRESUMABLY
INFECTED WITH ENTAMOEBA HISTOLYTICA IN CHILPANCINGO, GUERRERO,
MÉXICO. R. Javier-Reyna*, D. Flores-Robles, J. Flores de la Cruz, V. Pérez-Castillo and
P. Talamás-Rohana.
361
ENTAMOEBA HISTOLYTICA AND ENTAMOEBA DISPAR INTERACTION WITH
ENTEROPATHOGENIC BACTERIA SYNERGIZE DAMAGE TO EPITHELIAL CELLS,
AMPLIFYING THE INFLAMMATORY RESPONSE. J.M. Galván Moroyoqui*, M.
Domínguez Robles, E. Franco and I. Meza.
362
TRYPANOSOMA CRUZI GENOTYPE I STRAINS INDUCE DIFFERENT INFLAMMATORY REACTIONS IN HEART, SKELETAL MUSCLE AND LARGE INTESTINE IN A
MURINE MODEL. A. Vizcaino-Castillo*, R. Lira, I. Martínez and B. Espinoza.
363
LEISHMANIA LPG ACTIVATES TLR2 SIGNALING PATHWAY IN NK CELLS. E.A.
Fernandez-Figueroa*, I.C. Cañeda-Guzmán, N.L. Salaiza-Suazo, I.D. Becker and M.M.
Aguirre-García.
364
TOWARDS THE DEVELOPMENT OF AN ORAL VACCINE AGAINST CYSTICERCOSIS AND TAENIASIS USING TRANSGENIC PLANTS. J. Cervantes, M. Hernández, L.
Aguilar, N. Peña, J.L. Cabrera-Ponce, L. Herrera-Estrella, A. Guevara-Garcia, K. Willms,
G. Fragoso and E.L. Sciutto*.
365
NEUROCYSTICERCOSIS PATHOLOGY ASSOCIATED WITH THE LOCAL AND
SYSTEMIC IMMUNE RESPONSE. B.I. Saenz*, A. Fleury, A. Chavarria, G. Fragoso, C.
Márquez, J. Crispin, M. Vargas and E.L. Sciutto.
366
ANALYSIS OF IGA, IGM AND IGG ANTIBODY RESPONSES TO TRICHINELLA
SPIRALIS ADULT ANTIGENS DURING INFECTION IN THE RAT. D. MartínezAlarcon*, E. Navarrete-Ramirez and M.R. Salinas-Tobon.
367
SYSTEMIC AND INTESTINAL ANTIBODY RESPONSE AGAINST THE ADULT STAGE
OF TRICHINELLA SPIRALIS. E. Navarrete-Ramirez*, B.M. Coaxiloa-Mantecon, T.
Banda-Sánchez, F. Gomez-Martínez and M.R. Salinas-Tobon.
368
INTESTINAL CYTOKINE PRODUCTION PROFILE IN HAMSTERS EXPERIMENTALLY INFECTED WITH TAENIA SOLIUM CYSTICERCI. M. Cruz-Rivera*, G.
Vaughan, G. Avila and A. Flisser.
43
LIFE CYCLES, EPIDEMIOL
OGY
EPIDEMIOLOGY
369
DETECTION OF TOXOPLASMA IN PORK MEAT BY TISSUE CULTURE, BIOASSAY
IN MICE, ELISA, POLYMERASE CHAIN REACTION AND HISTOPATHOLOGY. M.
Galvan-Ramírez*, A.L. Madriz Elisondo, C.P. Rico Torres, H. Luna-Pastén, L.R.
Rodríguez Pérez, A. Rincon Sánchez, R.A. Franco Topete and D. Correa.
370
HUMAN CYSTIC ECHINOCOCCOSIS IN SLOVENIA. J. Logar*, B. Soba and T. LejkoZupanc.
371
A HOST–PARASITE LIST OF THE ADVANCED THIRD-STAGE LARVA OF GNATHOSTOMA BINUCLEATUM ALMEYDA-ARTIGAS, 1991 (NEMATODA: SPIRURIDA)
FROM FRESHWATER AND ESTUARINE FISHES AND THEIR POTENTIAL ROLE IN
LARVAL TRANSMISSION TO HUMANS IN MÉXICO. R.J. Almeyda-Artigas* and J.
Gaspar-Navarro.
372
EVALUATION OF A SALIVARY ANTIBODY IMMUNOASSAY FOR DETECTION OF
CRYPTOSPORIDIUM INFECTIONS. S.M. Hunt*, G.S. Fout, M.M. Rothermich, T.
Wade and A. Egorov.
373
PRESENT AND POTENTIAL DISTRIBUTION OF GNATHOSTOMA SPP. (NEMATODA: GNATHOSTOMATIDAE) IN MÉXICO. Y. Pérez-Alvarez, L. García-Prieto, D.
Osorio-Sarabia, V. León-Règagnon* and E. Martínez-Meyer.
374
SNOOK PARASITES AND THEIR POTENTIAL EFFECT IN PUBLIC HEALTH. L.
Garcia-Magaña*, S. López-Jiménez and R. Gamas-Triano.
375
RATE OF CHAGAS DISEASE IN THE STATE OF QUERETARO FOR POPULATIONS
UNDER 18 YEARS OF AGE. P.M.S. Salazar-Schettino*, G.S. García-De La Torre, M.
Cabrera-Bravo, M.I. Bucio-Torres, G.E. Rojas-Wastavino, A.L. Ruiz-Hernández, Y.
Guevara-Gómez, M.O. Vences-Blanco and E. Torres-Gutiérrez.
376
IMPORTANCE OF CLINICAL SCREENING IN THE INFECTION FOR TRYPANOSOMA CRUZI IN CANDIDATES TO BLOOD DONORS AND RISK ASSOCIATED
BACKGROUND. A.L. Ruiz-Hernández*, J. Rojo-Medina, M.I. Bucio-Torres, M.
Cabrera-Bravo, G. Estrada-García, P.M.S. Salazar-Schettino, G.E. Rojas-Wastavino, L.
Ruíz-González, M. Gutiérrez-Quiróz and Y. Guevara-Gómez.
377
CHARACTERIZATION OF INTERMEDIATE FORM DEVELOPMENTAL STAGES
DURING AMASTIGOGENESIS OF TRYPANOSOMA CRUZI. L.A. Hernández-Osorio*
and R.G. Manning-Cela.
378
CAN THE ANALYSIS OF THE HELMINTH PREVALENCE IN DOGS BE AN INDICATOR OF THE EARTH WARMING? P.M. Acevedo-Ramírez *, A. Rodríguez-Caballero,
R.I. Luna-Ochoa, G.E. Peralta-Abarca, M. Ponce-Macotela and M.N. Martínez-Gordillo.
379
PREVALENCE OF SWINE CYSTICERCOSIS IN THREE RURAL COMMUNITIES
FROM SOUTHERN MÉXICO. F. Cen-Aguilar*, R.D. Rodríguez Canul, J.A. Pérez Vega,
J.L. Dominguez-Alpizar, J.C. Allan and P.S. Craig.
380
A SEASONAL SURVEY OF HUMAN INTESTINAL PARASITES IN PATIENTS IN THE
ROCKY MOUNTAIN REGION OF COLORADO, USA. A. Neill, A. Hodd and C.
Church*.
44
381
MALACOLOGICAL FAUNA OF ACCOMPANIMENT OF FOSSARÍA HUMILIS AND F.
BULIMOIDES IN TWO SITES OF MÉXICO. I. Cruz-Mendoza*, M.T. Quintero-Martínez
and E. Naranjo-García.
382
SEROEPIDEMIOLOGY OF GIARDIASIS IN MÉXICO. R. Cedillo-Rivera*, Y. LealHerrera, L. Yépez-Mulia, O. Muñoz and M.G. Ortega-Pierres.
383
ECHINOCOCCUS SP. IN TRANSLOCATED ELK IN THE GREAT SMOKY MOUNTAINS NATIONAL PARK (GSMNP): A RE-EMERGING DISEASE? C. Cross, E.C.
Ramsay, S. Kania, A. Chapman and S. Patton*.
384
SOCIOCULTURAL AND HEALTH PRACTICES ASSOCIATED WITH TAENIA SOLIUM
TRANSMISSION. S. García-Cerecedo* and L. Vargas-Parada.
385
CHARACTERIZATION OF INTERMEDIATE FORM DEVELOPMENT STAGES DURING AMASTIGOGENESIS OF TRYPANOSOMA CRUZI. L.A. Hernández-Osorio*, S.
Martínez-Calvillo and R.G. Manning-Cela.
386
SEROLOGICAL EVIDENCE OF BORRELIA BURGDORFERI IN DOGS OF THE URBAN AREA OF MEXICALI, BAJA CALIFORNIA, MÉXICO. L. Tinoco-Gracia*, H.
Quiroz-Romero, M.T. Quintero-Martínez, T.B. Rentería-Evangelista, A. BarrerasSerrano, G. López-Valencia, S. Hori-Oshima, A.R. Tamayo-Sosa, A.P. Haro-Alvarez, M.
Moro and J. Vinasco.
387
SEROPREVALENCE AND DETECTION OF EHRLICHIA IN DOGS FROM VETERINARY CLINICS IN MEXICALI (MÉXICO)—PRELIMINARY RESULTS. A.P. HaroAlvarez, L. Tinoco-Gracia*, G. López-Valencia, T.R. Rentería-Evangelista, S. HoriOshima, G.E. Medina-Basulto and A. Barreras-Serrano.
388
SEROLOGICAL REACTIVITY TO TRYPANOSOMA CRUZI IN THREE COMMUNITIES OF MICHOACÁN, MÉXICO, WITH SAMPLES OF BLOOD IN FILTER PAPER
WITH HGI AND IFI. M. Gutiérrez-Quiroz*, S. Alvarado, L. Ruiz, A. Ruiz, G. Rojas and
Y. García.
389
POPULATION DYNAMICS OF PHILOMETRA CAROLINENSIS, AN OVARIAN PHILOMETRID IN THE SPOTTED SEATROUT (CYNOSCION NEBULOSUS) IN SOUTH
CAROLINA, U.S.A. G.R. Pérez, W.A. Roumillat, E.J. Levesque and I. De Buron*.
390
DEVELOPMENT OF PHILOMETRA OVERSTREETI AND PHILOMETROIDES PARALICHTHYDIS IN THE CYCLOPOID COPEPOD OITHONA COLCARVA. T. Bryan and I.
De Buron*.
391
BOOPHILUS MICROPLUS (ACARI: IXODIDAE) ON CATTLE DISTRIBUTION IN
NAVOLATO Y MOCORITO, SINALOA, MÉXICO. S.M. Gaxiola-Camacho*, M.T.
Quintero-Martínez, J.J. Portillo-Loera, N. Castro-Del Campo, J.E. Borbolla-Ibarra and J.
Ordoñez-Manriquez.
392
PRESENCE OF POPULATIONS OF HAEMATOBIA IRRITANS ON CATTLE OF
DOUBLE PURPOSE (MEAT AND MILK) IN PASTURING IN THE SOUTH OF
SINALOA STATE, MÉXICO. S.M. Gaxiola-Camacho*, M.T. Quintero-Martínez, J.E.
Borbolla-Ibarra, J.J. Portillo-Loera and N. Castro- Del Campo.
393
EVALUATION OF THE BIOLOGICAL REPRODUCTION OF TWO STRAINS OF
BOOPHILUS MICROPLUS. S.M. Gaxiola-Camacho*, Z. García-Vázquez, C. Cruz45
Vázquez, J.J. Portillo-Loera, M.T. Quintero-Martínez, C. Vásquez-Peláez and R. RosarioCruz.
394
POPULATION DYNAMICS OF THE PARASITIC STATE OF BOOPHILUS MICROPLUS
IN BOVINES OF THE MUNICIPALITY OF CULIACÁN, SINALOA, MÉXICO. S.M.
Gaxiola-Camacho, Z. García-Vázquez, C. Cruz-Vázquez, M.T. Quintero-Martínez*, J.J.
Portillo-Loera, C. Vásquez-Peláez, R. Rosario-Cruz and J.E. Borbolla-Inarra.
395
IDENTIFICATION OF ENDOPARASITES IN SNAKES BOIDAE, PITONIDAE AND
VIPERIDAE FAMILIES, FROM THE ZOO PARK IN CULIACÁN, SINALOA. S.M.
Gaxiola-Camacho, N. Castro-Del Campo, C. Barraza-Tizoc*, J.E. Borbolla-Ibarra, I.
Quintero-Osuna, N. Cárcamo -Aréchiga, S.D. Cota-Guajardo, Y. Villalba-Robles, J.
Gaxiola-Montoya, J.A. Pérez-Corrales, T. Martínez-Bastidas and M.A. RodríguezGaxiola.
396
NECROPSY RESULTS IN CAPUCHINO (ZEBUS APELLA) AND YELLOW HAND TITI
(CALLICEBUS TORQUATOS) MONKEYS. S.M. Gaxiola-Camacho, N. Castro-Delcampo,
C. Barraza-Tizoc*, J. Borbolla-Ibarra, N. Cárcamo -Aréchiga, Y. Villalba-Robles, S.D.
Cota-Guajardo, J. Gaxiola-Montoya, J.A. Pérez-Corrales, I. Quintero-Osuna, T.
Martínez-Bastidas, M.A. Rodríguez-Gaxiola, C. Sosa-Gutiérrez and E.G. Espínola-Ruiz.
397
COMPARISON BETWEEN SNAP 3DX AND CYTOLOGICAL TEST IN DIAGNOSTIC
FOR EHRLICHIA CANIS IN DOGS OF SINALOA, MÉXICO. C. Sosa-Gutiérrez*, S.M.
Gaxiola-Camacho, S.D. Cota-Guajardo, M.T. Quintero-Martínez, N. Castro Del Campo,
C. Barraza-Tizoc, N. Cárcamo-Aréchiga, J. Gaxiola-Montoya and J.A. Pérez-Corrales.
398
ZOONOTIC DERMATOPATHIES IN COMPANION ANIMALS IN SINALOA, MÉXICO.
S.M. Gaxiola-Camacho, S.D. Cota-Guajardo, N. Castro-Del Campo*, C. Sosa-Gutiérrez,
N. Cárcamo-Aréchiga, C. Barraza-Tizoc, J. Gaxiola-Montoya, J.A. Pérez-Corrales, J.
Borbolla-Ibarra, Y. Villalba-Robles, E.G. Espínola-Ruiz, K. Sicairos-Cañas, B. RomeroMéndez and M. Padilla.
399
GASTROINTESTINAL PARASITES IN DOGS AND CATS: UNDERESTIMATED ZOONOSES. S.M. Gaxiola-Camacho, S.D. Cota-Guajardo*, N. Castro-Del Campo, C. SosaGutiérrez, C. Barraza-Tizoc, N. Cárcamo-Aréchiga, J. Gaxiola-Montoya, J.A. PérezCorrales, J. Borbolla-Ibarra, Y. Villalba-Robles, M. Millán-Varela, C. Salgado-Vega and J.
Daniel.
400
TYPICAL AND ATYPICAL AMEBIC HEPATIC ABCESSES IN CHILDREN. EXPERIENCE OF 128 CASES TREATED AT THE INSTITUTO NACIONAL DE PEDIATRIA,
MÉXICO. O. Vázquez-Tsuji*, M.P. Márquez-Aguirre, T. Campos-Rivera, Y. Garcia-Yanez
and A. Rondán-Zárate.
401
OCULAR LARVA MIGRANS IN PEDIATRIC PATIENTS: A REPORT OF 10 CASES. O.
Vázquez-Tsuji*, T. Campos-Rivera and R.H. Medina-Campos.
TAXONOMY
TICS, PHYL
OGENY
AXONOMY,, SYSTEMA
SYSTEMATICS,
PHYLOGENY
402
46
DIGENEAN METACERCARIAE PARASITIZING THE HYDROMEDUSA CLYTIA
FOLLEATA (McCRADY, 1859) FROM NORTHERN QUINTANA ROO, MÉXICO. M.Y.
Morales-Hernández*, L. Aguirre-Macedo and M.L. Segura-Puertas.
403
INTESTINAL HELMINTHS IN CICONIIFORM BIRDS FROM THE CHUBURNA
SALTMARSH IN THE YUCATÁN PENINSULA. A.O. Barrera-Guzmán* and S. GuillenHernández.
404
RICHNESS AND ENDEMISM OF HELMINTH PARASITES OF FRESHWATER FISHES
IN MÉXICO. R. Aguilar-Aguilar*, A. Martínez-Aquino and R. Contreras-Medina.
405
COLECCION NACIONAL DE HELMINTOS (CNHE): 75 YEARS INVENTORYING
MEXICAN PARASITE DIVERSITY. R.M. Lamothe-Argumedo*, G. Pérez-Ponce de
León, L. García-Prieto and D. Osorio-Sarabia.
406
DIVERSITY OF TICKS IN MÉXICO: AN ANALYSIS OF RECENT ADVANCES. C.
Guzmán-Gornejo*, G. Montiel-Parra, R. Paredes-León and T.M. Pérez.
407
PHYLOGENETIC ANALYSIS OF SOME SPECIES OF THE GENUS POLYMORPHUS
LÜHE, 1911 FROM NORTH AMERICA (POLYMORPHIDAE: ACANTHOCEPHALA)
BASED ON MITOCHONDRIAL GENE SEQUENCES. M. García-Varela.
408
MORPHOLOGICAL AND MOLECULAR VARIATION IN OLIGOGONOTYLUS MANTERI WATSON, 1976 (DIGENEA: CRYPTOGONIMIDAE) IN MIDDLE-AMERICAN
CICHLIDS (OSTEICHTHYES: CICHLIDAE). U. Razo-Mendivil*, R. Rosas-Valdez and
G. Pérez-Ponce De León.
409
SCANNING ELECTRON MICROSCOPY OF SEVEN SPECIES OF POLYMORPHID
(ACANTHOCEPHALA) PARASITES OF BIRDS IN MÉXICO. B. Mendoza-Garfias*, M.
García-Varela and G. Pérez-Ponce De León.
410
KEY TO NEMATODES OF FRESHWATER FISHES IN MÉXICO. J.M. Caspeta
Mandujano.
411
CESTODES OF THE FAMILY DILEPIDIDAE FROM FISH-EATING BIRDS IN
MÉXICO. M.P. Ortega-Olivares*, T. Scholz and G. Salgado-Maldonado.
412
SPINILOCULUS (TETRAPHYLLIDEA) DIVERSITY IN BAMBOO SHARKS (ORECTILOBIFORMES: HEMISCYLLIIDAE) OF AUSTRALIA AND BORNEO. L. Desjardins*
and J.N. Caira.
413
GENETIC DIFFERENCES BETWEEN CYSTICERCI OF TAENIA SOLIUM ISOLATED
FROM HUMAN BRAIN AND FROM PIGS. A.C. Hinojosa-Juarez, G. Zúñiga, M.
Sandoval-Balanzario, S. González-Guzmán, D.P. McManus and A. Monroy-Ostria*.
414
PHYLOGENETIC RELATIONSHIPS OF EIMERIA (APICOMPLEXA: EIMERIIDAE)
PARASITES FROM SQUIRREL HOSTS BASED ON PLASTID ORF 470 DNA SEQUENCES. J. Casebolt*, D. Hofmann, C. Mandich, C. Oliver, D. Motriuk-Smith and R.S.
Seville.
415
PARASITE COLLECTIONS OF IMPORTANCE TO TROPICAL VETERINARY MEDICINE AT HARVARD UNIVERSITY’S MUSEUM OF COMPARATIVE ZOOLOGY. D.
Conn.
416
TAXONOMIC STUDY OF THE PHYLLOSOMA COMPLEX AND OTHER
TRIATOMINE SPECIES (INSECTA: HEMIPTERA: REDUVIIDAE) OF EPIDEMIOLOGICAL IMPORTANCE IN THE TRANSMISSION OF CHAGAS DISEASE: USING
ITS-2 AND MTCYTB SEQUENCE. F. Martínez, G. Villalobos, A. Cevallos, P. De La
Torre, J.P. Laclette, R. Alejandre-Aguilar and B. Espinoza*.
47
417
IDENTIFICATION OF A THIOESTER-CONTAINING PROTEIN (TEP) FROM THE
MALARIA VECTOR ANOPHELES ALBIMANUS. M. Garrido-Armas*, M. GonzálezLázaro, L. Cortés-Martínez, J. Martínez-Bartneche and F.D. Hernández-Hernández.
418
CHARACTERIZATION OF A SCAVENGER RECEPTOR IN THE MALARIA VECTOR
MOSQUITO ANOPHELES GAMBIAE. M. González-Lázaro*, L. Flores-Romo, M.
Rodríguez and F.D. Hernández-Hernández.
419
TRIATOMINE’S INFESTATION ASSOCIATED TO INDIVIDUAL AND DWELLING
FACTORS IN COMMUNITIES OF FOUR STATES OF MÉXICO (DGAPA IN205305). M.
Cabrera-Bravo*, G.E. Rojas-Wastavino, M.O. Vences-Blanco, J.S. Rosales-Piña, A.L.
Flores-Villegas, N.D. Luna-Chavira, G.S. García-De La Torre and P.M.S. SalazarSchettino.
2:30–3:00
COFFEE BREAK, Preconvene Area.
3:00–4:30
REMOVAL OF POSTERS, Regency 1.
Authors of Poster Session-3 remove their posters (341–419).
3:00–5:00
IMMUNOLOGY-2, Regency 2.
Presiding:
C.D. Davis, Western Kentucky University, Bowling Green KY, USA
G. Ávila, UNAM, México DF, México
Time
Paper
No.
3:00
420
EVALUATION OF CD4+, CD8+ AND GAMMA-DELTA (G-D) LYMPHOCYTES
IN THE ABOMASAL MUCOSA IN SHEEP WITH HIGH AND LOW RESISTANCE TO HAEMONCHOSIS. M.A. Muñoz-Guzmán, R. Domínguez-Martínez,
A. Buendía-Jiménez and F. Alba-Hurtado*.
3:15
421
ABOMASUM PLASMATIC CELLS (IG+-CEL): IN SITU EVALUATION IN
SHEEP WITH EXPERIMENTAL HAEMONCHOSIS. M.A. Muñoz-Guzmán*,
S.A. Hernández-Rivera, A.A. Ayanegui, G. Valdivia-Anda and F. Alba-Hurtado.
3:30
422
IDENTIFICATION OF NEW LEISHMANIA VACCINE CANDIDATES BY BIOINFORMATIC ANALYSIS OF LEISHMANIA MAJOR GENOME AND IN VIVO
VALIDATION. C. Najera-Herrera*, R. Piña-Aguilar, F. Xacur-Garcia, M.J.
Ramirez-Sierra and E. Dumonteil.
3:45
423
KINETICS OF THE IMMUNE RESPONSE IN THE INTESTINAL MUCOSA OF
HAMSTERS INFECTED WITH TAENIA SOLIUM ADULTS. G. Avila-Ramirez*,
L. Aguilar-Vega, S. Velasco-Velasco, F.J. Garcia-Vazquez, E. Farfan and A. Flisser.
4:00
424
HSP60 E. COLI PARTICIPATE IN THE EXPRESSION OF HUMAN BETA
DEFENSIN 2 IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMC).
M.D. Hernández-Córdova*, M.L. Domínguez-López and M.E. Cancino-Díaz.
4:15
425
ALBENDAZOLE’S EFFECTS ON RECOGNITION OF A TRICHINELLA SPIRALIS NEWBORN LARVAE’S 49 KDA ANTIGEN. R.A. Avendaño-Rabiella*, M.R.
Salinas-Tobon and J. Hernández.
48
4:30
426
PILOT CLINICAL TRIAL OF A THERAPEUTIC DNA VACCINE AGAINST
TRYPANOSOMA CRUZI INFECTION IN DOGS. I. Quijano-Hernández*, M.
Bolio-González, J. Rodríguez-Buenfil, M.J. Ramirez-Sierra and E. Dumonteil.
4:45
427
EFFECT OF ALBENDAZOL ON ANTIBODY RESPONSE AND ESTABLISHMENT OF TRICHINELLA SPIRALIS MUSCLE LARVAE IN INFECTED RATS. F.
Velasco-Rivera, R.A. Avendaño-Rabiella, J. Hernández-Sánchez and M.R. SalinasTobon*.
3:00–6:00
HOST–PARASITE INTERACTIONS-3, Regency 3.
Presiding:
L.F. Mayberry and J.R. Bristol, University of Texas, El Paso TX, USA
Time
Paper
No.
3:00
428
SUSCEPTIBILITY OF CRIOLLO AND SUFFOLK LAMBS TO HAEMONCHUS
CONTORTUS AFTER AN EXPERIMENTAL INOCULATION. E. RomeroEscobedo*, G. Torres-Hernández, F. Alba-Hurtado, C.M. Becerril-Pérez, M.A.
Muñoz-Guzmán and J. Solís-Ramírez.
3:15
429
ANALYSIS OF VARIABILITY OF CLONES OF TRYPANOSOMA CRUZI DERIVED FROM MEXICAN STRAINS BY BEHAVIOR IN MICE AND CULTURE
CELLS. M.A. Becerril-Flores* and P.M.S. Salazar-Schettino.
3:30
430
SPLEEN CELL PROLIFERATION DURING AND AFTER SKIN MYIASIS BY
HUMAN BOT FLY DERMATOBIA HOMINIS (DIPTERA: OESTRIDAE). A.C.
Leite*, J.G. Gonçalves, N.M. Breynees, V.C. Fernandes and A.M. Goes.
3:45
431
THE DIAGNOSIS OF PORCINE AND BOVINE CYSTICERCOSIS BY ULTRASONOGRAPHY. A. Schunemann-De Aluja*, S.C. Herrera-García, R.E. MéndezAguilar and E.L. Sciutto.
4:00
432
PARASITIC LUNGWORMS ASSOCIATED WITH HISTOPATHOLOGICAL
LESION IN NATURALLY INFECTED SHEEP. B. Coyote-Camacho*, M.U.
Alonso-Fresan, M.E. López-Arellano, R. Montes-De-Oca-Jiménez and E. LiebanoHernández.
4:15
433
PARTICIPATION OF SEXUAL HORMONES DURING EXPERIMENTAL AMEBIC LIVER ABSCESS IN HAMSTER. C. Cervantes-Rebolledo*, C.A. OrtízMartínez, M. Nequiz, J.P. Laclette and J.C. Carrero-Sánchez.
4:30
434
IN VITRO INTERACTIONS OF NEOPARAMOEBA PEMAQUIDENSIS WITH
FISH AND SHELLFISH CELL CULTURES. L.E. Lee.
4:45
435
LYMPHOMA DEVELOPED IN AN IMMUNE MOUSE WITH BURKITT HISTOPATHOLOGY FEATURES AFTER REPEATED INFECTIONS BY PLASMODIUM
YOELII YOELII. F. Malagón*, J. González, O. Castillo and E. Carrasco.
5:00
436
DEHYDROEPIANDROSTERONE INHIBITS THE ESTABLISHMENT,
GROWTH AND REPRODUCTION OF THE METACESTODE STAGE OF
TAENIA CRASSICEPS. J.A. Vargas-Villavicencio* and J. Morales-Montor.
49
5:15
437
SEX-STEROIDS ACCELERATE EVAGINATION OF THE SCOLEX IN THE
HUMAN PARASITE TAENIA SOLIUM: IMPLICATIONS TO THE HOST-PARASITE RELATIONSHIP. G. Escobedo*, C. Larralde and J. Morales-Montor.
5:30
438
IN VITRO DIRECT EFFECTS OF INSULIN ON TAENIA CRASSICEPS AND
TAENIA SOLIUM: ANOTHER MOLECULAR MECHANISM MEDIATING THE
HOST–PARASITE CROSSTALK. G. Escobedo*, M.C. Romano and J. MoralesMontor.
5:45
439
DIFFERENCES IN GASTROINTESTINAL PARASITES BETWEEN TWO GOAT
GENOTYPES IN THE DRY TROPIC OF MÉXICO. D. Camps Mota*, R.D.
Martínez Rojero, G. Torres-Hernández, E. Romero Callejas, C.M. Becerril Pérez
and J.C. García Carranza.
3:00–6:00
LIFE CYCLES, EPIDEMIOLOGY-2, Regency 4.
Presiding:
K. Sapp, High Point University, High Point NC, USA
Y. Garcia, UNAM, México DF, México
Time
Paper
No.
3:00
440
POPULATION AGE STRUCTURE OF DISCOCOTYLE SAGITTATA (MONOGENEA) IN FARMED RAINBOW TROUT, ONCORHYNCHUS MYKISS. M.
Rubio-Godoy* and R.C. Tinsley.
3:15
441
GYRODACTYLUS SP. INFECTION IN FOUR GENETIC GROUPS OF TILAPIA
FARMED IN VERACRUZ, MÉXICO. M. Rubio-Godoy*, G. Muñoz-Córdova, M.
Garduño-Lugo, G. Mercado-Vidal and M. Salazar-Ulloa.
3:30
442
IN VITRO REPRODUCTION AND SURVIVAL OF MICROPHALLUS
TURGIDUS (TREMATODA: MICROPHALLIDAE). O.J. Pung*, M.H. Lancaster,
C.E. Jarrous and E.D. Brown.
3:45
443
ZOONOTIC PARASITES OF UNUSUAL OCCURRENCE IN CANADA. T.W.
Gyorkos*, J. Dear, E. Kokoskin, A. Villeneuve, M. Ndao, B.J. Ward and J.D.
MacLean.
4:00
444
SEROPREVALENCE OF TOXOPLASMA GONDII ANTIBODIES IN SHEEP OF
PUEBLA, MÉXICO. H. Caballero-Ortega, H. Quiroz-Romero, S. OlazaránJenkins, H. González Henkel and D. Correa*.
4:15
445
BIOLOGY OF THE TROUT CECAL NEMATODE, TRUTTAEDACNITIS
TRUTTAE IN THE COLORADO RIVER, GRAND CANYON, ARIZONA: AN
UPDATE. R. Cole*, A. Choudhury and D. Reinitz.
4:30
446
ANALYSIS OF HOST BEHAVIORS AND ENDOPARASITIC INFECTIONS IN
MIGRATORY BIRDS FROM THE PURCHASE KNOB, GREAT SMOKY MOUNTAINS NATIONAL PARK, LAKE JUNALUSKA, NORTH CAROLINA USA. V.R.
Diderrich-Faulkner, C.T. Faulkner* and P.J. Super.
4:45
447
VETERINARIAN’S ROLE IN PREVENTING ZOONOTIC TRANSMISSION OF
INTESTINAL PARASITES FROM PET DOGS AND CATS TO PEOPLE. P.M.
Schantz.
50
5:00
448
TAENIA SOLIUM TAENIASIS AND CYSTICERCOSIS IN SOUTHERN MÉXICO,
1996-2005. R. Rodríguez Canul*, J.A. Pérez Vega, J.L. Dominguez-Alpizar, F.
Cen Aguilar, J.C. Allan and P.S. Craig.
5:15
449
SCIENCE COMMUNICATION AS A MEANS OF PREVENTING INFECTIOUS
DISEASES: DEVELOPMENT OF A HEALTH COMMUNICATION PROGRAMME FOR THE CRITICAL LEARNING OF HEALTH INFORMATION. L. VargasParada*, S. García, U. Rodríguez and M. Lozano.
5:30
450
MALARIA RELAPSE OR RE-INFECTION AND IMPACT IN THE TRANSMISSION AND PERSISTANCE OF THE DISEASE IN AFFECTED REGIONS OF
MÉXICO: SOME ADVANCES TO MOLECULAR IDENTIFICATION. L.
González-Ceron*, M.A. Sandoval, J.A. Nettel-Cruz, M.H. Rodríguez, V. Choy
and R. Gómez.
5:45
451
ULTRASTRUCTURE OF ORNITHODIPLOSTOMUM PTYCHOCHEILUS
DIPLOSTOMULA DURING INVASION OF THE BRAIN OF THE FISH INTERMEDIATE HOST. D. Conn*, C.P. Goater and D. Bray.
3:00–5:30
TAXONOMY, SYSTEMATICS, PHYLOGENY-3, Chichén Itzá 1-2.
Presiding:
D. Minchella, Purdue University, West Lafayette, Indiana, USA
F. Malagón, UNAM, México DF, México
Time
Paper
No.
3:00
452
THE IMPACT OF THE ARRIVAL OF HYSTRICOGNATH AND SIGMODONTINAE RODENTS ON THE PHYLOGENY OF NEOTROPICAL NEMATODES.
F.A. Jiménez* and S.L. Gardner.
3:15
453
EVOLUTIONARY RELATIONSHIPS OF GNATHOSTOMA SPP. (NEMATODA:
GNATHOSTOMATIDAE) INFERRED FROM MTDNA AND RDNA. V. LeónRègagnon*, F. Bertoni-Ruiz, L. García-Prieto, D. Osorio-Sarabia, R.M. LamotheArgumedo, A. Zaldívar-Riverón, H. Akahane, K. Ando and V. Crichton.
3:30
454
ANALYSIS OF DRYING METHODS FOR SCANNING ELECTRON MICROSCOPY OF PLATYHELMINTHES. J.G. Gates and S.S. Hendrix*.
3:45
455
ITS1-ITS2 RDNA SEQUENCES USED TO RECOGNIZE CRYPTIC SPECIES OF
EIMERIA (APICOMPLEXA: EIMERIIDAE) FROM SQUIRREL HOSTS. R.S.
Seville*, C. Oliver, A. Smith, B. Hanelt, S.V. Brant, C.M. Adema and D. MotriukSmith.
4:00
456
COMPARATIVE POPULATION GENETICS OF VETERINARY COCCIDIA IN
THE AMERICAS. B.M. Rosenthal*, I.M. Asmundsson, D.B. Dunams, C.
Madubata and J.P. Dubey.
4:15
457
PHYLOGENETIC RELATIONSHIPS OF SOME SPIRURIDEAN NEMATODE
GENERA PARASITIC IN NORTH AMERICAN FRESHWATER FISHES. A.
Schemmel, R. Rosas-Valdez, G. Pérez-Ponce De León and A. Choudhury*.
4:30
458
VARIATION IN THE COX1 MTDNA REGION FROM GEOGRAPHICALLY
DIVERSE SAMPLES OF PARAORYGMATOBOTHRIUM COLLECTED FROM
51
THE BLACKTIP SHARK, CARCHARHINUS LIMBATUS. T.R. Ruhnke*, R.L.
Turner and K. Jensen.
4:45
459
A CAPSALID MONOGENEAN FROM THREE SPECIES OF PARALABRAX
(PISCES: SERRANIDAE) FROM BAJA CALIFORNIA PENINSULA, MÉXICO.
M. Gomez Del Prado-Rosas* and R.M. Lamothe-Argumedo.
5:00
460
GLOBAL DEMOGRAPHIC AND PHYLOGENETIC CHARACTERIZATION OF
THE RABIES VIRUS. E.J. Dunham*, E.C. Holmes and H. Bourhy.
5:15
461
CHRONOLOGIC EVOLUTION OF THE ATTACHMENT OF NEOGRUBEA SPP.
(MONOGENEA: MAZOCRAEIDAE) TO GILLS: ONTOGENETIC AND TAXONOMIC IMPLICATIONS. J.S. Hernández*, F.E. Montero, M. Del-Dedo, B.
Beron-Vera, E.A. Crespo and J.A. Raga.
SUNDAY EVENING, JUNE 24
7:00–10:00 BANQUET, Quinta Montes Molina.
MONDAY MORNING, JUNE 25
9:00–10:00 BUEDING/VON BRAND LECTURE, Regency 3-4.
Presiding:
Time
J. Janovy, Jr., University of Nebraska, Lincoln NE, USA
Paper
No.
462
SOMETHING OLD, SOMETHING NEW, SOMETHING
BORROWED, SOMETHING BLUE: MODES OF
ACTION OF ANTHELMINTICS. R.J. Martin.
10:00–Noon ASP AWARDS AND BUSINESS MEETING, Regency 3-4.
Presiding:
S. Kayes, University of South Alabama, Mobile AL, USA
ASP Awards
C.P. Read Mentor Award Lecture
Introduction:
USA
E. Rowland, Ohio University, Athens OH,
The recipient of the 2007 C.P. Read Mentor Award is
RAYMOND E. KUHN, Department of Biology, Wake Forest
University, Winston-Salem NC, USA
463
52
WE ARE SCIENTISTS, BUT WE ARE IN THE PEOPLE
BUSINESS. R.E. Kuhn
Ashton Cuckler New Investigator Award
Introduction: V. Conners, University of South Carolina
Upstate, Spartanburg SC, USA
The recipient of the 2007 A. Cuckler New Investigator
Award is GREGORY J. SANDLAND, Purdue University,
West Lafayette IN, USA
Willis A. Reid Jr. ASP Student Research Competition Awards
Introduction:
L. Couch, The University of New Mexico, Albuquerque NM, USA
Undergraduate winner: Ken Kellner, Wheaton College, Norton MA, USA (Kristen
Page, Advisor)
Graduate winner: Jamie Kopper, Michigan State University, East Lansing MI (Linda
Mansfield, Advisor)
Best Student Paper and Travel Awards
Introduction:
T.J. Cook, Sam Houston State University, Huntsville TX, USA
ASP Business Meeting
10:00–Noon SMP AWARDS AND BUSINESS MEETING, Regency 2.
Presiding:
A. Flisser, UNAM, México DF, México.
u
53
ABSTRACTS
The content of the submitted abstracts, authors’ names, and affiliations are those of the submitting authors. Discrepancies in hyphenated surnames and incomplete institutional affiliations are as they were entered into the abstract
submission database. An attempt was made, however, to correct spelling and grammar, and to fill in missing institutional data, as time allowed before the publication deadline.
54
ABSTRACTS
1
A National Model for the Control of a Parasitic Disease: Human Cysticercosis in México. A. FLISSER*,
Microbiologia y Parasitologia, Facultad de Medicina, UNAM, J. NARRO, Dirección, Facultad de
Medicina, UNAM, J. CALDERÓN, Cómputo, Facultad de Medicina, UNAM, and G. MARTÍNEZ,
Facultad de Medicina, UNAM, México DF, México.
Cysticercosis is acquired by pigs after ingesting Taenia solium eggs released by human tapeworm carriers,
who acquire the infection after ingesting pork meat contaminated with cysticerci. Human neurocysticercosis (NCC) is due to the ingestion of T. solium eggs and has been considered a public health problem in
México for more than 20 years. The analysis of the number of NCC cases and of human taeniosis
reported in the National Epidemiologic Surveillance System between 1996 and 2005 shows a decreasing
trend. Also, about 30% of pig production is in backyards, where pigs have access to human feces.
Nowadays neurologists indicate commonly that fewer NCC patients request medical services and
veterinarians note that it is more difficult to find infected pigs. This information indicates that T. solium
has been controlled in México. This fact might be explained by the following actions: (1) General
improvement of living conditions in the Mexican Republic—for example, since the last cholera epidemic
in 1991, people wash their hands and fresh food; also, the streets in many cities and communities have
been asphalted and sanitary infrastructure and animal husbandry have improved; (2) specific measures
towards the control of T. solium, such as the publication of an Official Mexican Guideline for the control
and prevention of taeniosis/cysticercosis in 1994; standardization of modern diagnosis (imaging and
immunologic techniques); use of cestocidal drugs; and increase of expert neurologists and radiologists
and, in general, of medical and veterinary human resources; (3) development of basic and applied
research, since Mexican scientific publications have shown a trend from pathology to clinical aspects in
the decade of 1980, to epidemiology and control a decade later, and to basic biology and prevention
measures in this century. Also, about 20 Mexican research groups have been recognized nationally and
internationally in specialized and general meetings, conferences, financial support and publication of
books.
2
Conventional Wisdom and a Tale of Two Cytokines. S.G. KAYES, Department of Cell Biology and
Neuroscience, University of South Alabama, Mobile AL, USA.
Two cytokines active in inflammation have seemingly acquired functions that few would have predicted
or imagined. A receptor molecule known as Duffy Antigen Receptor for Chemokines (DARC) is
expressed on a subset of endothelial cells, which line the lumen of blood vessels. Following the interaction of IL-8 with DARC, neutrophils adhere to and cross the endothelium, thus establishing an acute
inflammatory response in the extracellular connective tissues. DARC also is expressed on the surface of
red blood cells where it participates in the adhesion of Plasmodium vivax (which expresses an IL-8-like
molecule) to red blood cells. DARC’s absence in African Americans and West Africans has been postulated to protect these individuals from P. vivax infection. The conventional wisdom is that sickle cell
anemia or not expressing Duffy antigen (i.e., DARC) protects these populations from malaria. The
conventional wisdom may not be correct. The second cytokine that defies conventional wisdom is the T
cell cytokine, macrophage migration inhibition factor (MIF). Macrophages take up and digest cellular
debris and antigenic molecules and after breaking down the latter, can present them to the immune
system to initiate an immune response. By inhibiting macrophage migration, their numbers build up at
sites of MIF release and can lead to an inflammatory reaction known as granuloma formation which is
seen in schistosomiasis, toxocariasis or tuberculosis. Downstream events of macrophage engagement in
the face of helminthic infection frequently include eosinophilia and increased levels of IgE antibody.
Defying the conventional wisdom, recent work has suggested that some helminths can release a MIF-like
homolog that can activate macrophages and recruit eosinophils to sites of worm-derived MIF deposition.
This would seem to raise the question of whether the inflammatory reaction observed following infection
is beneficial rather than detrimental to the parasite. Had Charles Dickens been an evolutionary immuno55
ABSTRACTS
parasitologist, he may have begun The Tale of Two Cytokines with the words, “They were the best of
cytokines, they were the worst of cytokines. . . . ”
3
Global Climate Change: Causes and Consequences. T.M. HALL, Goddard Institute for Space Studies,
NASA, New York NY, USA.
The global mean surface air temperature has increased by 0.8ºC since 1880, and the Earth is now
warmer than it has been for thousands of years. The case is very strong that this warming is due to
anthropogenic activity, and the greenhouse effect of industrial CO2 is the single biggest contributor.
Reponses to this warming are myriad and complex, and include both increases and decreases in regional
precipitation, possible intensification of tropical cyclones, and stress on terrestrial and marine ecosystems.
Sea level has risen by 2 mm/yr over the 20th century, increasing to 3 mm/yr in the past decade, in response to thermal expansion of the warming ocean and melting of alpine glaciers. Recent satellite data
shows slow, but accelerating reduction in the Greenland ice sheet volume, which may be a harbinger of
much greater sea-level rise. I review the physical basis for the connection of global warming to anthropogenic activity, presenting the major radiative forcing agents and discussing the climate sensitivity to these
forcings. Arguments based on ground-based and satellite measurements, paleo data, and climate model
simulations are made. I focus on several consequences of the warming, particularly recent trends in sea
level and the state of the Greenland and West Antarctic ice sheets. Finally, scenarios for future climate
change are discussed, and issues related to carbon-cycle feedbacks raised, which depend in complex ways
on ecosystem responses to warming.
4
Climate Change and Parasitism in Arctic and Subarctic Ecosystems. S.J. KUTZ*, Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada,
R. PEACOK and D. BENDER, Department of Geography, Faculty of Science, University of Calgary,
Calgary, Alberta, Canada.
Global climate change is altering the ecology of infectious agents and driving the emergence of disease in
people, domestic animals, and wildlife. In the Arctic, where many biotic and abiotic responses to global
climate change are already evident, dramatic alterations in biodiversity and epidemiology of infectious
diseases are anticipated. Arctic terrestrial ecosystems are characterized by high seasonality with long cold
winters and short, cool summers, and low parasite and host species diversity. Arctic species, including
ungulates, their pathogens and the invertebrate vectors, have evolved a variety of strategies to persist
under these constraints. As already demonstrated by shifted patterns of transmission for the muskox
lungworm, climate warming will release some parasites from these constraints and is expected to change
the dynamics and geographic distribution of other endemic parasites. Warming also will lead to the
breakdown of ecological barriers and result in new host–parasite associations (e.g., northern range
expansion of temperate host, parasite, and vector species). The response of various parasite taxa to
climate changes will differ, constrained by life history traits and tempered by host diversity, density,
immunocompetence, and behaviour. The seasonally defined, relatively simple arctic ecosystems provide
an ideal opportunity to investigate in real time the responses of high latitude host–parasite systems to
climate change and can provide insight into biotic implications of warming on a global scale. I will focus
on parasitism in arctic ungulates to illustrate key principles and questions relevant to arctic disease
ecology under a regime of climate change.
5
Climate Change, Vector-borne Avian Diseases and Endemic Hawaiian Forest Birds—What Will the
Future Bring?. C.T. ATKINSON*, B.L. WOODWORTH, D.A. LAPOINTE, U.S. Geological Survey, Pacific
Island Ecosystems Research Center, Hawaii Volcanoes National Park, Hawai’i HI, and M.D. SAMUEL,
Wisconsin Cooperative Wildlife Research Unit, University of Wisconsin, Madison WI, USA.
Hawaiian honeycreepers are spectacular examples of adaptive radiation, but face one of the highest rates
of extinction in the world. of more than 50 species and subspecies documented since discovery of the
islands by the Western world, only 13 are believed to be extant and more than half of these are critically
endangered. Both population declines and dramatic changes in the altitudinal distribution of native birds
56
ABSTRACTS
have been tied closely to the introduction of mosquito vectors, avian malaria (Plasmodium relictum)and
avian pox virus (Poxvirus avium). In this presentation, we will discuss how climate interacts with biotic
components of this disease system, affecting transmission across steep altitudinal gradients of temperature and rainfall. Keys to sustaining the remaining diversity of this endemic avifauna likely lie at the
extremes of these altitudinal gradients, both in the lowlands where natural selection is fostering evolution
of disease resistance and in remaining high elevation refugia where restoration efforts are seeking to
improve and expand habitat.
6
Climate Change as a Driver of Infectious Disease Change. K.D. LAFFERTY, Marine Science Institute,
University of California, Santa Barbara CA, USA.
Climate change scientists predict an increase in global average temperatures, increased sea level and
altered precipitation and humidity patterns. Two crisis perspectives have developed surrounding climate
change. These warn of a loss in biodiversity and an increase in infectious diseases. Both are important
problems for society, but the present focus on the negative effects of climate change might obscure the
scientific process by excluding from consideration changes that might increase biodiversity or decrease
parasites. For instance, one can make a case that some aspects of climate change that decrease biodiversity will also decrease infectious disease (and vice versa). There may be value in stepping back from a
crisis perspective of climate change so that we can address the full spectrum of potential changes in
disease. Increased temperature is most likely to act on free-living parasite stages, or on parasites of
ectotherms, or on the resistance of ectothermic hosts. The relationship between temperature and vital
rates is hump-shaped (not linear). So, while host and parasite spatial and seasonal distributions will shift
with increasing temperature, it is not necessarily the case that parasite distributions will expand with
increasing temperature. The survivorship of free-living parasite stages and hosts with aquatic stages are
likely to change with changes in humidity and precipitation, indicating that the direction of change in
such parasites will vary from region to region. Overall, parasite biodiversity is tied directly to free-living
biodiversity. Biodiversity loss due to climate change will lead to losses of parasite biodiversity because
host extinction and decline will lead to parasite extinction and decline. For instance, sea-level rise will
submerge low-lying islands and lead to loss of endemic hosts and their parasites. The same may happen
for species with ranges limited to high altitudes or latitudes. Finally, while climate affects a species’
potential range, control programs presently limit infectious diseases (such as malaria) to fragments of
their former range, indicating that climatic factors are not the sole factors responsible for the distribution
of diseases of modern humans. Future studies investigating the effect of climate on infectious disease
should take into account the alternative hypotheses that parasites may decline as well as increase with
climate change.
7
Proteomic Analysis of Sporozoites Reveal Highly Conserved Trap-like Molecules in Two Strains of
Eimeria maxima M6 and GS. S.A. EL-ASHRAM* and J.R. BARTA, Department of Pathobiology, University of Guelph, Guelph, Ontario, Canada.
Eimeria maxima is a widely distributed pathogen of chickens that causes both clinical and subclinical
disease in commercial broiler and broiler-breeder operations. Two immunologically distinct strains of
Eimeria maxima were examined in this study—the M6 strain (a single oocyst clonal line) and the Guelph
strain (GS, a single oocyst-derived line). In an attempt to find differences between the strains that might
explain observed strain-specific immune responses, the sporozoite proteome from each strain was
examined using 1- and 2-dimensional SDS-PAGE analyses. Less than 10% of the detected proteins of the
sporozoites of each strain differed from one another. One difference that was detectable using 1-D SDSPAGE was a pair of high molecular weight proteins designated GS 267.1 and M6 272.5 to reflect their
apparent molecular weights of 267 and 272kDa, respectively. Matrix-assisted laser desorption ionizationtime of flight (MALDI-TOF) analysis of the M6 272.5 band tentatively identified this protein as a
thrombospondin-related adhesive protein (TRAP)-like molecule (EmTFP250) that had been characterized previously from a different strain of Eimeria maxima. Based on PCR with four pairs of specific
primers using genomic template DNA from each strain, the TRAP-like molecule was shown to be
present in both strains of E. maxima. Using a further pair of specific primers, we amplified the function57
ABSTRACTS
ally critical transmembrane region and determined that the TRAP-like molecules from both strains had
identical cytoplasmic, transmembrane and adjoining extracellular sequence, and that this sequence also
was identical to GenBank sequence data for this molecule from other E. maxima strains. We conclude
that the differences in apparent molecular weight observed at the proteomic level between these strains
may be differences in primary sequence of the molecules in the N-terminal regions of the extracellular
portion of this molecule and/or post-translational modifications to one or either of these molecules.
8
Parasite Communities Discern Distinct Pacific Sardine (Sardinops sagax) Populations in the California
Current. R.E. BALDWIN*, Oregon State University, CIMRS, Hatfield Marine Science Center, Newport
OR, and K.C. JACOBSON, NMFS, NOAA Fisheries, Hatfield Marine Science Center, Newport OR,
USA.
The Pacific sardine (Sardinops sagax) fishery crashed in the 1950s off the coasts of Oregon and Washington states (USA); however, the fishery resumed in 1999. As a result, there is a renewed interest in
reassessing their management in the California Current off western North America. Macroparasites have
been used successfully as biological tags to differentiate between populations of various fish species in the
past, but the potential to separate Pacific sardine populations using macroparasites is a new approach in
an ongoing, multidisciplinary study between fisheries scientists from Canada, the United States and
México. Sardines initially collected in 2005 were moderately infected with six parasite species, with an
overall prevalence of less than 53%. Non-metric multidimensional scaling (MDS) ordination of parasite
communities suggests that there are at least three sardine populations between Vancouver Island (British
Columbia, Canada) and Point Arguello (California, USA). However, to assess the temporal stability of
macroparasite communities, new sardine collections were made in the same regions in 2006. Three
trematode species—Lecithaster gibbosus, Parahemiurus sp, and Myosaccium ecaude—have emerged as
potential biological tags. These initial data support the idea that macroparasites can be good biological
indicators important for the management of Pacific sardine populations in the California Current.
9
Life-history Cost of Trematode Infection in Helisoma anceps Using Mark–Recapture in Charlie’s Pond,
N.J. NEGOVETICH* and G.W. ESCH, Department of Biology, Wake Forest University, Winston–Salem,
NC, USA.
Parasitism has the potential to affect key life-history traits of an infected host. Perhaps the most studied
interactions are in snail–trematode systems, where infection can result in altered growth rates, survival,
and/or fecundity of the individual. Positive correlations between host size and parasite prevalence are
often attributed to changes in growth rates or mortality, which have been observed in the laboratory.
Extending lab-based conclusions to the natural setting is problematic, especially when environmental
conditions differ between the laboratory and the field. The present study utilizes reproduction experiments and mark–recapture methods to directly measure key life-history traits of the pulmonate snail
Helisoma anceps in Charlie’s Pond. Based on previous laboratory and field experiments on H. anceps, we
predict a significant reduction in fecundity, but not growth rate or survival, of infected snails. Individual
capture histories were analyzed with multistate models to obtain estimates of survival and infection
probabilities throughout the year. Recaptured individuals were used to calculate specific growth rates.
Trematode infection resulted in complete castration of the host. However, neither survival nor growth
rates were found to differ between infected and uninfected individuals. The probability of infection
exhibited seasonal variation, but did not vary with size of the snail. These results suggest that the correlation between host size and trematode prevalence is not due to differential mortality or changes in growth
rates. Instead, the infection accumulates in large snails via the growth of smaller, infected individuals.
10
The Energetic Costs of Parasitism in an Intermediate Host. S.E. LETTINI* and M.V. SUKHDEO, Ecology,
Evolution and Natural Resources, Rutgers University, New Brunswick NJ, USA.
Acanthocephalan parasites often alter energy budgets in their arthropod intermediate hosts by directing
energy away from reproduction towards growth. We investigated the ability of Acanthocephalus tehlequahensis to alter the energy budget in the isopod Caecidotea communis. Bomb calorimetry was used to
58
ABSTRACTS
quantify the allocation of ingested energy (kilojoules) to the host’s growth, reproduction and respiration,
and to parasite growth in infected and uninfected isopods. Infected isopods ate significantly more leaf
detritus and were significantly larger than uninfected isopods, but allocated significantly less energy to
growth and reproduction and more energy to respiration than uninfected isopods. Additionally, the
efficiency at which energy was converted to production (i.e., growth, reproduction, and the parasite) was
significantly less in infected isopods. In infected isopods, 79% of the production energy was allocated to
growth, 21% to the parasite, and 0% to reproduction, while in uninfected isopods, 61% of the production energy was directed to growth and 39% to reproduction. These data quantitatively support the idea
that acanthocephalans have significant effects on the energy budgets of their intermediate isopod hosts.
11
Patterns of Eugregarine Diversity in Damselflies in Four East Texas Ponds. J.C. GARCIA*, T.J. COOK,
Department of Biological Sciences, Sam Houston State University, Huntsville TX, and R.E. CLOPTON,
Department of Natural Sciences, Peru State College, Peru NE, USA.
More than 25 species of eugregarines have been described from the insect order Odonata (dragonflies
and damselflies). Intensive sampling over the past three years in the Primitive Big Thicket of East Texas
has identified numerous odonate species (both larvae and adults) infected with gregarines. We examined
the eugregarine fauna in damselfly larvae from four ponds in East Texas to investigate patterns of diversity. A total of 693 damselflies was collected, dissected and examined for gregarine infection from March–
July 2006. Eleven species of damselflies were collected from Double Lake (9.3 hectares, surrounded by
wooded camp sites); 10 species of damselflies were collected from Collins Pond (1.2 hectares in a
wooded, secluded area of the Big Sandy Unit of the Big Thicket National Preserve); five species of
damselflies were collected from Gibbs Pond 1 (0.4 hectares in open cattle pasture located at the Sam
Houston State University, Gibbs Ranch) and four species of damselflies were collected from Gibbs Pond
2 (8–10 m in diameter in open cattle pasture). Unfortunately, we did not recover gregarine oocysts from
any damselfly and thus were not able to identify gregarines to the specific level. However, we were able
to identify tentatively gregarines to the generic level based on epimerite structure. We recovered the
genus Hoplorhynchus from Enallagma vesperum, Enallagma geminatum, Enallagma basidens and
Nehalennia integricolis and the genus Steganorhynchus from the damselflies Ishnura posita and Ishnura
hastata. We recovered gregarines from five damselfly species at Double Lake, three species at Collins
Pond, one species at Gibbs Pond 1, and three species at Gibbs Pond 2. Assuming the paradigm of strict
host specificity among gregarines, there was no correlation between host richness and gregarine richness.
There also was no correlation between size of habitat or type of habitat (open vs. wooded) and number
of damselfly species infected. (Supported by NSF grants DEB0340782, DEB0340774, and
DBI0353538.)
12
Predicting West Nile Virus (WNV) Dynamics Using Local Habitat Characteristics. W.D. ROSSITER*,
Ecology and Evolution, Rutgers University, New Brunswick NJ, M. VITULLO, Center for Remote Sensing
and Spatial Analysis, Rutgers University, New Brunswick NJ, and M.V. SUKHDEO, Ecology and Evolution, Rutgers University, New Brunswick NJ, USA.
Spatial and temporal variation of environmental characteristics is thought to shape transmission dynamics in West Nile Virus (WNV). Habitat-based risk analyses can aid in understanding these dynamics and
in forecasting potential outbreaks. We have created a predictive model for WNV presence in mosquito
populations of New Jersey using a combination of mosquito trap collection data, remote sensing and
geographic information system (GIS) technologies. A local reference point (1 km radius) was created
around each collection location (N = 78), and each sample plot was characterized using a digital sampling technique for multiple habitat and community layers (land use, topography, hydrology, vector
abundance, and mosquito community richness). Sample plots were grouped a priori as either WNVpositive or WNV-negative based on empirical data from the 2003 census for each county. Using a
canonical analysis of discriminance (CAD), we determined that land use and topographic slope contributed most to the WNV presence in local mosquito populations. Using these predictive variables, we
constructed a habitat characterization scheme to classify habitat types that could potentially harbor
WNV-positive mosquito populations in the future.
59
ABSTRACTS
13
Population Dynamics of Daubaylia potomaca (Nematoda: Rhabditida) in Helisoma anceps. L.E.
CAMP*, N.J. NEGOVETICH, G.W. ESCH and H.E. EURE, Department of Biology, Wake Forest University, Winston–Salem NC, USA.
Infection with the nematode parasite Daubaylia potomaca has been documented from Helisoma spp. in
various locations throughout the United States. Most recently, infection with D. potomaca was found in
H. anceps from Mallard Lake, a pond in the Piedmont region of North Carolina. Mallard Lake exhibits
differences in the population dynamics of H. anceps compared to Charlie’s Pond, a pond in the same
region where many years of work on H. anceps has been conducted. Another difference between the two
bodies of water is the presence of D. potomaca–this parasite has not been detected in Charlie’s Pond. In
Mallard Lake, the prevalence of D. potomaca is observed to be low in the fall (from 1–17%), while large
increases in its prevalence (up to about 60%) are seen upon resumption of collections in the spring.
Helisoma anceps are known to go into aestivation during the winter months, indicating that recruitment
of parasites over this time period is due, in large part, to activity of D. potomaca at low temperatures.
Infection intensity can be very high with this nematode, with some individual snails carrying D. potomaca
adults in excess of 100 worms. The present study will detail characteristics of infection with D. potomaca
in H. anceps, as well as review life cycle details of the nematode.
14
How Large Is the Hand Inside the Puppet? The Evolutionary Ecology of Infection Mass of 15 Trematode
Parasitic Castrators of the Estuarine Snail, Cerithidea californica. R.F. HECHINGER*, Department of
Ecology, Evolution and Marine Biology, University of California, Santa Barbara CA, K.D. LAFFERTY and
F.T. MANCINI, III, Marine Science Institute, University of California, Santa Barbara CA, and A.M.
KURIS, Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara
CA, USA.
Parasitic castration is an adaptive strategy where the parasite usurps its host’s phenotype, including the
host’s reproductive effort. Though castrators are generally known to be large relative to typical parasites,
their mass has rarely been quantified and little is known about size variation, even if such variation exists.
We hypothesize that castrator species vary in optimal allocation to survival versus production, and
consequently differentially manipulate resource budgets of infected host phenotypes. Consequently, we
predicted that castrator species using the same host would differ in body mass, which is used primarily
for production. We quantified the parasite/host mass of 15 species of trematode that castrate the same
snail host species. Trematode species took 14–39% (mean = 20.3%) of an infected snail’s mass. Body
mass varied among trematode species according to family, host-tissues used, and position in their competitive dominance hierarchy. Intraspecific variation in castrator mass fluctuated with variables that
covary with energy available for host reproduction. Specifically, trematode mass was 24% higher in
summer than winter, 15% greater on flats than in channels, and increased with host mass to the 1.5
power. Indicating absolute constraints of parasitic castration, mixed-species infections were not additive,
increasing in mass only 38% more than single-species infections. Our findings suggest that parasitic
castrator mass, although always large, does vary and is influenced by ecological constraints and life
history trade-offs between reproduction and survival.
15
Coprological and Serological Diagnosis of Anoplocephala perfoliata Infection in Southern Alberta
(Canada) Horses: Preliminary Data. S.L. SKOTAREK*, C.P. GOATER, Department of Biological Sciences,
University of Lethbridge, Lethbridge, Alberta, Canada, and D.D. COLWELL, Lethbridge Research
Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada.
The distribution of Anoplocephala perfoliata in western Canada is not well described. Given the potentially
serious consequences of infection with this tapeworm, it has become important to determine the risk
factors for horses in southern Alberta, Canada. A prior study of the spatial and temporal occurrence of A.
perfoliata in faecal samples collected during the winter and summer of 2006 indicated prevalence of 18%
and 8%, respectively. Significant differences in prevalence were noted between pastured and non-pastured
horses during both sampling seasons. Regional differences also were noted, with drier pastures of the
60
ABSTRACTS
eastern region having significantly lower prevalence than central and western regions, suggesting that
pasture conditions are an important factor. Samples collected at a local abattoir served as the gold
standard for evaluating diagnostic techniques. Feces and sera were collected and the caecum was inspected for presence of tapeworms. Examination of caecae indicated a preliminary prevalence of 7% for
A. perfoliata. Western blots using 12/13kDa tapeworm excretory/secretory (E/S) antigen showed these
horses also were serologically positive.
16
Life Cycle Variation in the Genus Rhabdias: A Tale of Snakes and Frogs. G.J. LANGFORD* and J.
JANOVY, JR., School of Biological Sciences, University of Nebraska, Lincoln NE, USA.
Members of the nematode genus Rhabdias are among the most commonly encountered helminths of
amphibians and reptiles around the world. In the United States and Canada, Rhabdias spp. infect the
lungs of two host groups: amphibians and snakes. These host groups have drastically different life
histories, yet they share morphologically similar parasites. This is a common theme in many parasite
clades; however, few clades provide a host–parasite system that is amenable to both laboratory and field
manipulations. The genus Rhabdias provides an ideal system to address these types of problems. To
determine the life history strategies of lung nematodes, a series of experiments were designed to uncover
the life cycles and host specificity of snake and anuran lungworms. These experiments demonstrated that
anuran Rhabdias spp. display varying degrees of host specificity within anurans, infect host via skin
penetration, have a heterogonic reproductive strategy, and have a relatively short lifespan. Snake lungworms exhibited almost no host specificity (even lizards were infected in the laboratory), infect host’s via
oral ingestion, have both heterogonic and homogonic reproduction, and have a relatively long lifespan.
Overall, these experiments showed a vast variation in life cycles between amphibian and snake Rhabdias
spp. In an attempt to understand the subsequent variation in life history, since these two groups of
lungworms shared a common ancestor, we explored several aspects of host ecology and abiotic factors
that may affect transmission strategies in lungworms. Results suggest that host ecology plays a large role
in transmission strategies used in different Rhabdias spp. by dictating the avenues of transmission
available to each species.
17
The Genome Project of Taenia solium. A. GARCIA-RUBIO, Instituto de Biotecnología, UNAM, México,
R.J. BOBES, J.C. CARRERO-SÁNCHEZ, Instituto de Investigaciones Biomédicas, UNAM, México, M.A.
CEVALLOS, Centro de Ciencias Genómicas, UNAM, México, K. ESTRADA, Instituto de Biotecnología,
UNAM, México, J.L. FERNÁNDEZ, Centro de Ciencias Genómicas, UNAM, México, G. FRAGOSO,
Instituto de Investigaciones Biomédicas, UNAM, México, P. GAYTÁN, Instituto de Biotecnología,
UNAM, México, V.M. GONZÁLEZ, Centro de Ciencias Genómicas, UNAM, México, L. JIMÉNEZ,
Facultad de Medicina, UNAM, México, V.M. JOSÉ, Instituto de Investigaciones Biomédicas, UNAM,
México, M.S. JUÁREZ, Instituto de Biotecnología, UNAM, México, A. LANDA, C. LARRALDE, L.
MENDOZA, Instituto de Investigaciones Biomédicas, UNAM, México, J. MORALES-MONTOR,
Instituto de Investigaciones Biomédicas, UNAM, México, E. MORETT, Instituto de Biotecnología,
UNAM, México, E.L. SCIUTTO, Instituto de Investigaciones Biomédicas, UNAM, México, X.
SOBERÓN, Instituto de Biotecnología, UNAM, México, P. DE LA TORRE, Instituto de Investigaciones
Biomédicas, UNAM, México, V. VALDÉS, Facultad de Ciencias, UNAM, México, J. YÁÑEZ, Instituto de
Biotecnología, UNAM, México, and J.P. LACLETTE*, Instituto de Investigaciones Biomédicas, UNAM,
México.
We have constituted a consortium of key laboratories at UNAM to carry out a full genomic project for
Taenia solium. Genome size estimated through cytofluorometry on isolated cyton nuclei is 270 Mb. In
contrast, the rate of recovery of new sequences after sequencing 1.2 gigabases suggests a genome size of
120–140 Mb. Final assembly will consider a coverage of 20X from the 454 sequencer and 3–5X from
capillary sequencing. ESTs sequencing is completed; 14,113 adult and 9,157 larva quality checked ESTs
have been deposited in GenBank. Out of the initial 23,290 ESTs, 19,067 were incorporated into 2,564
genes (contigs). We have ~6,800 “genes,” including the contigs, plus 2,592 larva and 1,611 adult ESTs
that remained as solitons. The 349 most highly expressed genes account for 50% of all transcripts. Many
are differentially expressed between larva and adult. Approximately half of the 6,800 genes have a
61
ABSTRACTS
significant match in SwissProt. Gene Ontology categories can be assigned to 36%: 2,448 genes. About
27% of the genes have no match in SwissProt + TREMBL (expect > 1e-3), and could constitute new
genes. Our results suggest that the genome of T. solium is not highly repetitive (~7%). One small (53
bp) tandem-repeat represented 0.5% of the genome. Different tetranucleotide repeats of the form (Txxx)
accounted for about 4.5% of the genome. The consortium makes a worldwide call for collaborative
research. (An IMPULSA-UNAM Project.)
18
Parasitic Nematodes—From Genomes to Control. M. MITREVA*, Y. YIN, J. MARTIN, S. ABUBUCKER
and R. WILSON, Genome Sequencing Center, Washington University School of Medicine, St. Louis
MO, USA.
Parasitic nematodes of humans, animals and plants cause diseases of major socio-economic and agricultural importance globally. Molecular characterization of these parasites, as well as the development of
new techniques for diagnostics and control, can benefit from genomic approaches. As an entrée to
characterizing parasitic nematode genomes, we generated ~ 300,000 expressed sequence tags (ESTs)
from 31 non-Caenorhabditis nematode species. These transcriptomic data, coupled with the existing
whole genomic data, were used as a resource to identify phyla-specific proteins that nematodes have
adapted after diverging evolutionarily from other animals. Proteins with specificity to nematodes may
serve as excellent targets for drugs with low toxicity to humans and other vertebrates or for environmentally safe pesticides. We developed a computational based method that can detect highly conserved
regions in a robust fashion. The identified putative coding sequences conserved across the phylum
Nematoda or nematode subgroups were named ‘Nematode-specific Multi-species Conserved Sequences’
(NMCSs). We identified 611 NMCSs, with, on average, 10 ± 8 species per group and an average
alignment length of 176 ± 99 amino acids (aa). One hundred eighty of these (30%) had the
Caenorhabditis elegans gene with known RNAi phenotype following transient gene knockout. In addition, 509 groups included only parasitic nematode species, and therefore assigned as parasitism-specific,
with an average of 6 ± 13 species per group and 119 ± 64 aa average alignment length. The strongest
NMSC models are the ones spanning the phylum Nematoda. We will report on the progress of identification of NMCSs including extensive functional classification for those with homology. (Projects details
available at www.nematode.net; project funded by NIH-NIAID-46593 grant.)
19
A Multidisciplinary Approach to Understanding the Role of Sand Fly Proteins in Leishmania Transmission. J.G. VALENZUELA*, F. OLIVEIRA, J.M. ANDERSON, S. KAMHAWI, R. JOCHIM, C. TEIXEIRA, R.
GOMES, D. ELNAIEM and N. COLLIN, Vector Molecular Biology Unit, Laboratory of Malaria and
Vector Research, NIAID, NIH, Rockville MD, USA.
Parasite–vector and vector–host interactions are fundamental for a successful pathogen transmission in
vector-borne diseases. In order to understand these interactions at the molecular level, we followed a
multidisciplinary approach based on cDNA sequencing, proteomics, bioinformatics, biochemical and
immunological assays of sand fly salivary gland and midgut proteins. With this approach we have
characterized the most abundant transcripts from the midgut of various sand flies including Phlebotomus
papatasi and identified the receptor on this sand fly responsible for the parasite attachment and survival
on this insect. Furthermore, we have characterized the transcripts that are modulated by the acquisition
of a blood meal and more importantly the midgut transcripts that appear to be modulated by the parasite
Leishmania major. Transcripts coding for the most abundant sand fly salivary gland secreted proteins also
were identified. A functional genomic approach based on high-throughput DNA plasmid construction
and immunization allowed us to identify the sand fly salivary proteins that produced a cellular immune
response and protected animals against Leishmania infection. These data will contribute to the understanding of pathogen–vector, vector–host molecular interactions and in a more practical use these data
suggest that vector midgut proteins are important targets for transmission blocking vaccines and that
vector salivary proteins represent an important component for a vector-based anti-Leishmania vaccine.
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ABSTRACTS
20
Comparative Genomics of Parasitic Protists: Better the Bug You Know. J.M. CARLTON, Department of
Medical Parasitology, New York University School of Medicine, New York NY, USA.
In recent years, the study of eukaryotic parasites has undergone a revolution with the availability of vast
amounts of genome sequence data from many of the species that make up this eclectic grouping. Two
major groups of parasites, protists and helminths, account for most of the human suffering and agricultural loss caused by pathogenic eukaryotes, and in very many cases the available anti-parasitic therapeutics, i.e., drugs and vaccines, are woefully inadequate or becoming obsolete as parasite species develop
resistance. Thus, genome sequence data, and in particular comparative genome sequence analysis,
provides an alternative for development of novel therapeutics through the identification of parasitespecific genes, metabolic pathways and molecular mechanisms of parasite phenotypes. In this presentation, I will first describe the current status of parasitic protist genome sequencing and genomics. Then I
will provide specific examples of how comparative genomics is being used to identify novel drugs,
vaccines and genetic markers for the treatment, prophylaxis and surveillance of several important diseases, with particular emphasis on Plasmodium, the malaria parasite. Thus, the presentation will illustrate
some of the first steps being taken to harness the power of comparative genomics in the discovery, design
and application of therapies for diseases.
21
Colonization of Freshwater Fishes by Introduced Parasites. W.F. FONT, Department of Biological
Sciences, Southeastern Louisiana University, Hammond LA, USA.
In México, the number of species of introduced freshwater fish helminths (n = 21) exceeds the number
of endemic helminths (n = 15), a testament to the power of humans to alter natural fish parasite communities (Salgado-Maldonado, 2006). Anthropogenic introductions of parasites may bypass natural
constraints to colonization such as geographic distance and geological barriers. Yet, even for human
introductions, colonization may be difficult and taxa differ in their likelihood of becoming established.
Biological characteristics of different taxa allow predictions regarding which parasites are more or less
likely to colonize new geographic areas and fish hosts. In general, because they utilize more motile
definitive hosts, allogenic parasites are more likely than autogenic species to colonize, and then subsequently to expand their geographic ranges once established in a new area. Monogenea have direct life
cycles and are more likely to be introduced by transferring their fish hosts to new areas. Because of their
narrow host specificity, however, monogenes are less likely to switch hosts and infect the native fishes
found there. Because of their typically strict specificity to molluscan first intermediate hosts and their
requirement for a second intermediate host, Trematoda are, in general, less likely to be successful colonists. However, Centrocestus formosanus is now widely distributed in North America because of the
concomitant importation of its snail host, Melanoides tuberculata. Intermediate host requirements
constrain colonization of Cestoda and many Nematoda as well, but for certain species like Bothriocephalus
acheilognathi and Camallanus cotti, the occurrence of ubiquitous intermediate hosts like copepods may
enhance opportunities for establishment. Insight into the probability of fish parasite colonizations in
North America can be gained by comparing the occurrence of exotic parasites in Hawaiian stream fishes
where constraints are even greater than on the continent.
22
North American Freshwater Fishes and Their Parasites: Patterns and Processes in Biogeography. A.
CHOUDHURY, Division of Natural Sciences, St. Norbert College, DePere WI, USA.
The historical biogeography of enduring associations between North American freshwater fishes and
their metazoan parasites is explored in the tradition of parascript studies. The North American freshwater fish fauna is a rich and diverse assemblage comprising clades of fishes showing various combinations
of endemism, vicariant holarctic distribution, marine derivation, and continental colonization. Patterns of
associations of the core helminth fauna (emphasis on trematodes and nematodes) in groups of fishes
exhibiting such fundamental patterns of historical biogeography (e.g., sturgeons, catfishes, suckers and
basses) are examined and reviewed. Results suggest that: (a) hypotheses of the historical biogeography of
more basal holarctic families (acipenserids, salmonids, esocids) are largely consistent with the biogeogra63
ABSTRACTS
phy of their parasite faunas; (b) more recent clades such as percids and cyprinids show considerable
deviation from this pattern; (c) catostomids and ictalurids harbor a well-established core helminth fauna
consistent with their biogeographical affinities; (d) there is increasing evidence of host-shifting in the
southern transitional regions reflected in the parasite fauna of the nearctic fish fauna; and (e) the historical colonization of North American freshwater environments from marine environments by ancestors of
hosts such as Centrarchidae allow us to develop testable hypotheses of parasite relationships.
23
Helminth Diseases in Aquaculture, with an Emphasis on Catfish, Nematodes and Trematodes. R.M.
OVERSTREET, Gulf Coast Research Laboratory, Department of Coastal Sciences, The University of
Southern Mississippi, Ocean Springs MS, USA.
Helminth parasites and resulting diseases can have a severe influence on the productivity and survival of
freshwater fish aquaculture. These parasites consist of both adult and developmental stages and of many
different taxonomic groups. Nematodes usually cause an esthetic problem because many are large enough
to be seen by the seafood consumer. A few nematodes affect growth or reproduction of the fish host, and
a few comprise a public health risk. Trematodes, in addition to those that affect the appearance of the
product and pose public health risks, include several species that can kill or harm a large portion of the
crops, resulting in greatly decreased production and even closing of the facilities. of special importance
are diplostomoids, heterophyids, clinostomes and aporocotylids. Recently, a few diplostomoids have had
a major influence on catfish culture in both the U.S. and Latin America, especially the metacercariae that
have caused widescale mortalities of channel catfish at aquaculture farms in Louisiana, Mississippi and
Arkansas, U.S.A. However, since harmful catfish parasites are transmitted by birds, management practices require considerable biological information on the fish, bird and snail hosts as well as the parasites.
Snail control seems to provide the most feasible approach. (This material is based upon work supported
by the National Science Foundation under Grant Nos. 0529684 and 0608603.)
24
Parasites, Food Webs and Ecosystem Stress. D.J. MARCOGLIESE, Fluvial Ecosystem Research Section,
Aquatic Ecosystem Protection Research Division, Environment Canada, Montreal, Quebec, Canada.
Parasites are natural biological information units that can reveal profound insights about their hosts and
their roles in local food web. Many parasites have complex life cycles that depend on predator–prey
interactions for completion. Abundance and species composition of parasites, therefore, are influenced by
the structure of the food web within ecosystems. Thus, any stressor that affects food web structure by
altering any of its components also affects the flow of parasites through that web. Depending on the
nature of the impact of a particular stressor in an ecosystem, certain predictions can be made concerning
how parasite populations, guilds or communities may be affected, based on knowledge of their life
cycles. For example, acidification causes a reduction in parasite diversity by eliminating digeneans
because molluscs, their required intermediate hosts, are not tolerant of low pH. In the case of eutrophication, prevalence and richness of myxozoans may be enhanced due to proliferation of their oligochaete
alternate hosts. However, predictions from other environmental perturbations such as contaminants may
be less intuitively obvious, due to conflicting direct and indirect effects on host–parasite systems and
unforeseen effects on the ecosystem itself. Direct effects include toxicity to free-living and exposed stages
that, theoretically, should decrease parasite abundance, while indirect effects include host immunosuppression that, theoretically, should increase abundance. In addition, there may be a threshold contamination level that leads to clear effects on parasites below which effects are not easily discernible. To complicate matters further, confounding factors at a regional scale can affect patterns of parasite species
abundance and composition at the local level. Such factors include distribution and abundance of avian
hosts, climatic weather patterns and landscape fragmentation. Lastly, parasites themselves may affect food
web structure by interacting with other stressors in polluted ecosystems.
25
Perturbing the Dimer Interface of Triosephosphate isomerase and Its Effect on Trypanosoma cruzi. V.
OLIVARES-ILLANA, Department of Biochemistry, Instituto de Fisiología Celular, UNAM, México DF,
México, A. RODRÍGUEZ-ROMERO, Department of Biochemistry, Instituto de Química, UNAM,
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ABSTRACTS
México DF, México, I.D. BECKER, M. BERZUNZA-CRUZ, Department of Experimental Medicine,
Facultad de Medicina, UNAM, México DF, México, J. GARCÍA, Facultad de Química, UNAM, México
DF, México, N. CABRERA, Department of Biochemistry, Instituto de Fisiología Celular, UNAM, México
DF, México, F. LÓPEZ-CALAHORRA, Department of Organic Chemistry, Universidad de Barcelona,
Barcelona, Spain, M. TUENA DE GÓMEZ-PUYOU, Department of Molecular Genetics, Instituto de
Fisiología Celular, UNAM, México DF, México, A. GÓMEZ-PUYOU and R. PÉREZ-MONTFORT*,
Department of Biochemistry, Instituto de Fisiología Celular, UNAM, México DF, México.
In the American Continent, approximately 18 million people are affected by Chagas disease, caused by
Trypanosoma cruzi. There is no satisfactory cure for the disease because current drugs have serious side
effects and are useless in the chronic stage of the disease. Thus, more effective new drugs are urgently
needed. We have been searching for molecules that are detrimental to the life of the parasite by targeting
a central enzyme of the glycolytic pathway: triosephosphate isomerase. This enzyme, which is a homodimer that is catalytically active only in its dimeric form, has been validated as a target in a closely related
trypanosomatid: Trypanosoma brucei. Since there are important differences in the interface of the enzymes
from the parasite and humans, we have searched for small molecular weight compounds that specifically
disrupt the contacts between the two subunits of the enzyme from T. cruzi without affecting the enzyme
of Homo sapiens, and examined if such a compound could kill the parasite. We found that dithiodianiline
(DTDA) causes total inactivation of recombinant triosephoshate isomerase from T. cruzi (TcTIM) at
nanomolar concentrations. In contrast, the concentration needed to inactivate the recombinant human
enzyme was 400 times higher. Since DTDA is a disulfide, we tried its effect in four mutants of TcTIM in
which each of its four cysteines was replaced with either valine or alanine. The sensitivity of the mutants
to DTDA was very similar to that of wild type TcTIM. The crystal structure of TcTIM that had been
soaked in DTDA, together with the data on the mutants, showed that inactivation resulted from alterations of the dimer interface. We also found that DTDA prevented the growth of Escherichia coli cells that
had been transformed with TcTIM, but had no effect on normal E. coli. In addition, DTDA killed
epimastigotes of T. cruzi in culture. We show that by targeting the dimer interface of oligomeric enzymes
from parasites, it is possible to discover small molecules that kill the parasite with a high level of selectivity.
26
Antiparasitic Drug Discovery Via Mechanism-based Screening: Will It Succeed? T.G. GEARY, Institute
of Parasitology, McGill University, Montreal, Quebec, Canada.
The current paradigm for drug discovery in the pharmaceutical industry, high-throughput mechanismbased screening, relies on the testing of millions of compounds in micro-assay formats for the ability to
affect the function of a recombinant protein. It was introduced widely in the mid-1980s and into antiparasitic drug discovery programs, mostly in veterinary contexts, shortly thereafter. In the larger pharmaceutical arena, the rate of success of this technology in finding new kinds of drugs that affect novel
targets has been much lower than hoped. In the parasite arena, we have yet to see a new class of compound introduced to the field after having been discovered in a biotechnology-based screen. As this
strategy becomes entrenched in academic/NGO-driven drug discovery programs, it is important to
consider the reasons underlying the lack of success to date and to suggest modifications that may increase
productivity. of all therapeutic areas, chemotherapy of infectious disease, including parasitisms, should be
the most rewarding for mechanism-based screening. Choice of a target for screening is not the successlimiting step. Is the quality of the library of chemicals available for screening the key variable? Most
chemical collections have been assembled based on activity against non-parasite related diseases, and
contain a low proportion of structures with high affinity for invertebrate or protozoal proteins. One key
task for groups interested in target-based antiparasitic drug discovery is to generate, for wide use, a highquality chemical collection, including natural products, that maximizes structural diversity, so that this
hypothesis can be tested.
27
Understanding the Direct and Indirect Effects of Supplementary Feeding to Reduce the Need for
Anthelmintic Treatments in Small Ruminants. J.F. TORRES-ACOSTA*, A.J. AGUILAR-CABALLERO and
65
ABSTRACTS
C.A. SANDOVAL-CASTRO, FMVZ, Universidad Autónoma de Yucatán, Mérida, Yucatán, México, and
H. HOSTE, UMR 1225 INRA/DGER, Ecole Nationale Veterinaire Toulouse, Toulouse, France.
Sustainability of grazing/browsing small ruminant production systems depends on the successful control
of infections with gastrointestinal nematodes (GIN). However, farmers need to reduce their reliance on
the sole use of commercial anthelmintic (AH) drugs for the control of GIN. Several novel approaches
that reduce the dependence on AH treatment for the control of GIN have been sought. Manipulation of
the animal’s diet is a promising example. Evidence produced from recent trials in the tropics is used to
confirm that sheep and goats may improve their resilience and resistance against GIN through supplementary feeding. If an adequate level of supplementation is achieved, improvement of resilience can
reach the productivity of a worm-free animal. Also, supplemented animals may have a reduction in worm
burdens in the region of 50 to 60% compared to non-supplemented animals browsing under the same
conditions (P > 0.05). These trials help to illustrate that this novel approach can be economically viable
with browsing sheep and goats in spite of previous expectations from controlled infection trials. However, the possible mechanisms in charge of improving resilience and/or resistance warrants further
investigation. Some supplements (energy, protein, energy and protein) may increase the availability of
nutrients in the animal, which in turn may fuel its growth and/or immune response (indirect mechanism). However, under some browsing conditions, the use of a supplement may induce a shift towards
more consumption of browsing legumes and less grass and herbs. Two possible consequences may be: (a)
an increased consumption of tannins with a direct anthelmintic effect on the worms, and (b) a reduction
in the consumption of infective larvae from this high stratum of vegetation. Further studies are needed to
explore these mechanisms in order to understand and manipulate them for the benefit of farmers.
(Acknowledgement: ECOS-France/ANUIES-CONACYT-México [Project M03-A03].)
28
Mechanisms and Markers of Macrocyclic Lactone Resistance in Nematode Parasites of Humans and
Animals. R. PRICHARD, McGill University, Institute of Parasitology, Ste. Anne de Bellevue, Quebec,
Canada.
Macrocyclic lactone (ML) endectocides, such as ivermectin (IVM) and moxidectin, act by opening
glutamate- or GABA-gated chloride channels (GluCl and GABA Cl, respectively). Resistance to MLs,
and particularly to IVM, has become widespread in nematode parasites of livestock and IVM resistance
has now developed in the human parasite, Onchocerca volvulus. Despite the published effects of gene
deletion of GluCls on reducing the susceptibility of Caenorhabditis elegans to IVM, there is limited
evidence for the involvement of GluCl or GABA Cl genes in ML resistance. Recent studies, however,
indicate that changes in a number of ABC transporter genes, including the expression levels of some Pglycoproteins, are implicated in ML resistance in Haemonchus contortus and other nematodes, with
different ABC transporters responding to different MLs. In addition, MLs appear to be selecting on the
β-tubulin gene. This has implications not only for ML resistance, but also for benzimidazole (BZ)
resistance selection and BZ-resistance SNP detection. Similar to H. contortus, IVM resistance in O.
volvulus, which appears to be manifested by reduced suppression of reproduction, also involves selection
on some ABC transporters and β-tubulin. ABC transporters may be involved in regulating the concentrations of ML anthelmintics in the parasite, while IVM appears to interact directly with β-tubulin to alter
the stability of microtubules. Based on a developing knowledge of the mechanisms of IVM resistance, a
number of markers have been identified which may be useful for monitoring for IVM resistance in H.
contortus and O. volvulus.
29
TLR2 Activation in NK Cells of Patients Infected with Leishmania mexicana. I.D. BECKER*, Departamento de Medicina Experimental, Facultad de Medicina, UNAM, I.C. CAÑEDA-GUZMÁN, E.A.
FERNANDEZ-FIGUEROA, N.L. SALAIZA-SUAZO and M.M. AGUIRRE-GARCÍA, Departamento de
Medicina Experimental, Facultad de Medicina, UNAM.
Leishmania mexicana produces two forms of cutaneous leishmaniasis: localized cutaneous leishmaniasisis
(LCL), where an ulcer forms at the site of the parasite inoculation, which is associated with a strong
cellular immune response, and diffuse cutaneous leishmaniasis (DCL), characterized by nodules containing large numbers of parasites that spread throughout the skin devoid of hair. These patients have a poor
66
ABSTRACTS
cellular response. The cause of the uncontrolled spread of the parasite remains unknown; currently, it is
accepted that the decisive events of the immune response occur during the innate phase. Recently, our
group described that Leishmania LPG activates NK cells through TLR2, leading to the production of
IFN-γ, TNF-α and an increase in the TRL2 expression. In the current work, we analyzed the signaling
pathway leading to the NK cell activation by LPG through TLR2. By means of immunoprecipitations,
we found that TLR2 stimulation through LPG leads to the recruitment of MyD88, IRAK1, TRAF6,
IKK-α, IKK-β and NEMO, IkB-α with nuclear translocation of NF-kB p65 and p50. We also analyzed
the NK cell response of patients with LCL and DCL stimulated with Leishmania mexicana LPG. We
found differences between the NK cell response of LCL and DCL patients. Whereas in LCL patients,
LPG induces a significant increase in IFN-γ and TNF-α production as well as TLR2 upregulation, in
DCL patients there was no response in cytokine production nor modification of the TLR2 expression. In
LCL patients, there was an increase in NF-kB p65 and p50 translocation when cells were stimulated with
LPG. On the other hand, in a DCL patient, there was an intense expression of NF-kB p65 in basal
conditions, which was not altered with the LPG stimulus. These data indicate that in DCL patients there
is a dysregulation in the stimulation of TLR2 with LPG. In DCL patients there is a possible exhaustion
of NK cells due to the continued intense stimulus to which the cells are subjected in the heavily parasitized DCL patients. (Grants: CONACyT 47256 and DGAPA IN221806.)
30
Proinflammatory Responses to Malaria Infection and Cell Signaling Mechanisms. C.D. GOWDA,
Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine,
Hershey PA, USA.
Malaria, caused by various Plasmodium species of protozoan parasites, is a major public health crisis
around the world, afflicting ~500 million people and causing ~two million deaths annually. Unregulated, excessive production of proinflammatory mediators during parasite infection are thought to play an
important role in malaria pathogenesis. Several lines of evidence indicate that glycosylphosphatidylinositol (GPI) anchor glycolipids of Plasmodium falciparum are the major, if not exclusive, molecules responsible for inducing production of proinflammatory responses by the host innate immune system. Parasite
GPIs consist of EtN-P-6(Manα1-2)Manα1-2Manα1-6Manα1-4GlcN, linked to insoitol-acylated phosphatidylinositol (PI) by an α(1-6)-glycosidic bond. The structure of P. falciparum GPIs differ considerably from those of animals or other protozoan parasites. Previously, it has been proposed that GPImediated cell activation and innate immune responses are mediated by the activation of a cell-surface
protein tyrosine kinase and a cytoplasmic protein kinase C. These two kinases collaborate to initiate
downstream activation of NF-kB and the production of proinflammatory mediators. Recent studies,
however, have shown that the parasite GPIs function as specific pattern recognition molecules and are
recognized mainly by TLR2 and to a lesser extent by TLR4. TLR1 is the major co-receptor for TLR2
recognition of parasite GPIs. The signals initiated by TLR2/TLR1 complex are transduced to the cells
through the MyD88 adaptor protein, leading to the activation of MAPK (ERK, p38 and JNK) and NFkB signaling pathways and cytokine gene transcription. The various MAPK pathways and the members
of NF-kB cascade differentially contribute to GPI-mediated production of various proinflammatory
mediators. In vivo studies using a mouse malaria model have shown that GPI-mediated signaling contribute significantly to malaria pathogenesis. (Supported by the Grant AI 41139 from the NIAID, NIH.)
31
Actin Structural Organization in Entamoeba histolytica Trophozoites by Fibronectin Signaling. P.
TALAMÁS-ROHANA*, Departamento de Patologia Experimental, CINVESTAV, A. RIOS, Unidad
Monterrey, CINVESTAV-IPN, Monterrey, N.L, V. HERNÁNDEZ-RAMÍREZ and J.L. ROSALES-ENCINA,
Departamento de Patologia Experimental, CINVESTAV.
It has been shown that actin cytoskeleton and the functions that depend on this organelle are important
for E. histolytica pathogenesis. Using an in vitro model of trophozoites interaction with human fibronectin (FN), it has been possible to gain insight as to how the actin cytoskeleton functions. During
invasion, trophozoites establish contact with host components through cell surface molecules that act as
receptors. In our laboratory, we have worked for several years with a FN receptor molecule (EhFNR),
which shows functional and antigenic characteristics similar to integrins and is able to trigger a signaling
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ABSTRACTS
process conducting to the formation of a signaling molecular complex. Rho A, a small GTPase, controls
the generation of stress fibers and focal adhesions in response to mitogens, lisophosphatidic acid (LPA),
bombesin, and fetal calf serum. Evidence has accumulated that Rho-like GTPases in amoeba participate
as key regulators in the assembly of the actin cytoskeleton. We explored whether the multiplicity of actin
structures in FN-stimulated trophozoites depended on RhoA activation. A comparative analysis was
done of the effect of LPA, serum or absence of serum in RhoA activation in trophozoites incubated on
FN or glass. RhoA was found in its active state in cells stimulated by FN with or without LPA or serum.
Trophozoites incubated on glass showed RhoA activation only when LPA was added. A very low GAP
activity was found with FN, serum or LPA, accordingly with the activated state of RhoA, able to bound
to Rock-2, confirming the active state of the GTPase and the kinase. The effect of a Rock-2 inhibitor was
evident for LPA-treated cells, but it was not as effective for cells incubated on FN. In addition, the
activation of MAPK and LIMK-2 was analyzed by western blot, showing a differential activation pattern
depending on the stimulation condition. Taken together, these results strongly suggest that in addition to
G-protein coupled receptors, other signaling pathways are participating in the actin structuration when
cells are triggered by FN through the amoebic EhFNR.
32
Molecular Signaling in Larval Schistosoma mansoni: Gene Profiling the Miracidium-to-Sporocyst
Transition. T.P. YOSHINO, Department of Pathobiological Sciences, University of Wisconsin, Madison
WI, USA.
Parasitic helminths, like other organisms, rely on chemical signals to communicate with their external
environment, as well as for communication within and between cells comprising their internal environment. However, due to the sheer complexity of molecular events associated with host invasion, multistage development, growth and proliferation, little is known about the signaling networks involved in
coordinating the differential gene expression required for carrying out the “programs” necessary for
parasite survival within its host. Recently, we applied gene microarray (MA) and serial analysis of gene
expression (SAGE) approaches to identify genes associated with common signaling pathways and their
differential expression during the in vitro transition from the free-living miracidium to the mother
sporocyst stage of Schistosoma mansoni. Combining gene profiling analyses with this simple culture
system, we have started to identify and evaluate functionally the signaling pathways associated with larval
stages undergoing fundamental changes from the free-living to parasitic states. Functional analyses
include: (1) differential expression of specific signaling genes that provide hints of their direct involvement in larval development, (2) determining the expression of signaling genes in response to specific
stimuli (e.g., oxidative stress) indicating linkages between signaling pathways and putative functions, and
(3) targeting identified signaling genes for knockdown by RNAi to evaluate their potential role in larval
development. Using SAGE and MA methods, numerous signal-related genes have been identified
including G-protein coupled receptors, kinases, accessory proteins, etc. A substantial portion appears to
be expressed differentially between miracidia and sporocysts.
33
Caveolin-1 and Cholesterol Play a Major Role in the Development of Trichinella spiralis Oocytes. G.M.
ORTEGA-PIERRES, Departamento de Genética y Biología Molecular, CINVESTAV, México DF, México.
Caveolins are integral membrane proteins implicated in cholesterol homeostasis and transport, endocytosis mechanisms and regulation of signal transduction in differentiated cells. We have identified a caveolin1 gene from the nematode parasite T. spiralis (CavTs). For this, a stage-specific cDNA library of 3-day-old
adult worms was screened using a stage-specific cDNA labeled-probe. A selected clone contained a
cDNA insert of 1,427-bp and a full length ORF of 687-bp, which encodes for a 229 polypeptide with a
MW of 26 kDa. Confocal laser microscopy analysis using antibodies against CavTs and cross-sections of T.
spiralis adult parasites showed that CavTs is gradually accumulated in the ova and later on in the oocyte
membrane, reaches a maximum expression at day 3 pi and decreases during newborn larva development.
RT-PCR assays with specific CavTs primers using 1 to 4 days old parasites showed a similar gene expression profile as the one observed for CavTs suggesting a developmental regulation for CavTs gene. Free
cholesterol in female worms as detected by filipin staining was mainly distributed in germ line and in the
oocyte membranes as was observed for CavTs suggesting a temporal membrane association of cholesterol
68
ABSTRACTS
with CavTs for proper functions. When cyclosporin A (CsA) was given to mice during infection with T.
spiralis and worms were collected a different times post-infection it was observed that development of
oocytes was practically abolished in female worms. Also, indirect immunofluorescence staining in
sections of adult worms using anti-CavTs antibodies showed that CavTs had a lower expression and an
irregular distribution in the oocyte membranes in female worms collected from CsA treated rats as
compared with parasites obtained from untreated control rats. All together these results suggest that
CavTs plays a role in oocyte maturation during development of ML to adult parasites demonstrating a
specific gender expression of this gene.
34
Pocket Gophers and Chewing Lice: New Discoveries in an Old System. M.S. HAFNER, Museum of
Natural Science, Louisiana State University, Baton Rouge LA, USA.
The high incidence of cospeciation between pocket gophers and their chewing lice was first reported
almost two decades ago in the journal Nature. That study was the first to document cospeciation statistically in any host–parasite system, and it was the first to base such documentation on molecular evidence.
Subsequent to that discovery, cospeciation has been documented for many additional species of pocket
gophers and their lice, and the gopher–louse system has become literally a text-book example of cospeciation. Although interesting in their own right, continued reports of cospeciation in previously unstudied
species of pocket gophers and their lice have contributed relatively little to our understanding of the
behavioral, ecological, physiological, and other evolutionary mechanisms underlying cospeciation. This
report focuses on the few studies that have attempted to address the “how” and “why” of cospeciation in
the gopher–louse system. Some of these new discoveries lead to the intriguing possibility that chewing
lice are not parasites, but rather commensals or mutalists of pocket gophers.
35
Reef Fishes Have Higher Parasite Diversity at Unfished Palmyra Atoll Compared to Fished Kiritimati
Island. K.D. LAFFERTY, USGS, Western Ecological Research Center, University of California, Santa
Barbara CA, J.C. SHAW* and A.M. KURIS, Department of Ecology, Evolution and Marine Biology,
University of California, Santa Barbara CA, USA.
Parasites of fishes were lower at Kiritimati than at Palmyra, two coral atolls in the Central Pacific Line
Islands. We sampled five fish species—Chromis margaritifer, Plectroglyphidodon dickii, Paracirrhites arcatus,
Acanthurus nigricans and Lutjanus bohar—for helminth and arthropod endoparasites. Parasite diversity
was higher at Palmyra compared to Kiritimati for all five fish species. Fishes from Palmyra also tended to
have more parasites species per individual fish, higher parasite prevalence and higher parasite abundance
than did fishes from Kiritimati. Lower parasitism at Kiritimati may result from a simplified food web
due to overfishing. Low biodiversity could impair parasite transmission by reducing the availability of
hosts required by parasites with complex life cycles. Most notably, abundances of larval shark tapeworms
at Kiritimati were lower, presumably because fishing has depleted sharks in comparison to Palmyra.
36
Food Web Stability Drives Parasite Species Diversity. T.K. ANDERSON* and M.V. SUKHDEO, Department of Ecology, Evolution and Natural Resources, Rutgers, The State University of New Jersey, New
Brunswick NJ, USA.
Parasite species richness, heterogeneity and abundance are functions of host community composition and
dynamics. This study examined the metazoan parasite community in the mummichog, Fundulus heteroclitus, within the New York–New Jersey Harbor Estuary complex. Four distinct salt marsh areas were
selected, reflecting a gradient in host species diversity (H = 0.29, 0.31, 0.33, 0.37) and time postrestoration (control, 0 year, 9 year, 19 year). A total of 480 fish were studied, 30 collected in each of the
four seasons between 2006–07. Eleven taxa of metazoan parasites were identified: nematodes Dichelyne
bullocki and Contracaecum sp.; the digenean Lasiotocus minutus and metacercaria of Ascocotyle diminuta,
Mesostephanus appendiculatoides, Posthodiplostomum minimum; monogeneans Fundulotrema prolongis and
Swingleus ancistrus; acanthocephalans Paratenuisentis ambiguous and Southwellina hispida (cystacanth); the
copepod Ergasilus funduli. These taxa infected more than 70% of the mummichogs examined. Parasite
intensity per host ranged from 1 to 127. Species richness and abundance of birds, fish and benthic
69
ABSTRACTS
macroinvertebrates varied between sites; increasing diversity in host species was not positively or negatively correlated with diversity in the parasite community. A neutral relationship between host and
parasite diversity was observed; parasite species richness and abundance did not vary between sites.
Measures of food web stability (connectance) and structure (nestedness) were strong predictors of the
parasite community.
37
Parasites of Fishes from the Colorado River and Selected Tributaries in Grand Canyon, Arizona. C.
LINDER*, Department of Biology, University of Wisconsin, La Crosse WI, T. HOFFNAGLE, Oregon
Department of Fish and Wildlife, La Grande OR, B. PERSONS, Arizona Game and Fish, Phoenix AZ, A.
CHOUDHURY, Department of Biology, St. Norbert College, De Pere WI, and R. COLE, National
Wildlife Health Center, USGS, Madison WI.
Since the closure of the Glen Canyon Dam (GCD) in 1963, the Colorado River has seen drastic changes
and many exotic species introduced. These new fish species introduced non-native parasites that may
cause increased stress on and mortality of native fish populations. Proposed thermo-controlling devices
on GCD would return the main stem of the river closer to former natural conditions to favor growth and
reproduction of native fishes. Those conditions, however, also favor growth and development of Asian
tapeworm Bothriocephalus acheilognathi, which has been implicated in the decline of humpback chub
(Gila cypha). More information was requested by the Grand Canyon Monitoring and Research Center
before any restorative measures are implemented. During June and July 2006, we sampled eight tributaries and seven sections of the Colorado River from Lee’s Ferry to Diamond Creek using a variety of
sampling techniques, including electroshocking, seining and angling. Our objectives were to document
prevalence and distribution of fish parasites. A total of 717 fish were collected belonging to four native
species and eight non-native species. To date, one species of crustacean (Lernaea cyprinacea), two species
of trematodes (Ornithodiplostomum sp. and Posthodiplostomum sp.), one species of monogena (Octomacrum sp.), three species of cestodes (B. acheilognathi, Megathylacoides giganteum and Corallobothrium
fimbriatum), and four species of nematodes (Rhabdochona sp, Truttadaecnitis truttae, Contracaecum sp.
and Eustrongylides sp.) have been identified. Parasite–host associations were typical of those documented
previously. Identifications continue on leeches and myxozoans, and examinations of blood smears and
gills for protozoan and monogenean parasites, respectively, continue.
38
Leaving the Nest: The Genetic Distribution of Parasites in Snails That Serve as First and Second Intermediate Hosts. J.T. DETWILER* and D.J. MINCHELLA, Biological Sciences, Purdue University, West
Lafayette IN, USA.
A fundamental question in evolutionary parasitology is: why do parasites utilize several host species at
multiple points in their life cycle? In our echinostome–snail system, the snail species Lymnaea elodes
serves as a first intermediate host, and several snail species, including L. elodes, can serve as second
intermediate hosts. Given that a single host can serve simultaneously as both a first and second intermediate host, a new question arises: do parasites propagules re-colonize the same host from which they are
produced? Selection would be expected to favor colonization of novel second intermediate hosts because
of the highly virulent larval stages within the first intermediate host. For echinostomes, the redial stage
produces many propagules, castrates the host, and leads to early mortality, whereas the subsequent
metacercarial stage has significantly fewer fitness effects on the host. We assessed genotypes of both
rediae and metacercariae in single snails to test the prediction that genotypes between the two larval
stages would differ. Hosts were collected from spatially explicit points in a wetland where two snail
species co-occur with L. elodes. Utilizing microsatellite markers, we found snails were (1) infected
exclusively by metacercariae with the same genotypes as rediae, (2) infected with the same as well as
different metacercarial genotypes from that of the rediae, and (3) individuals with no overlapping
genotypes between the parasite stages. Our results suggest that in the environment, parasite genotypes
tend to exhibit several transmission patterns. The role of biotic and abiotic factors in generating these
patterns will be discussed.
70
ABSTRACTS
39
Pattern of Protein Carbonylation Following Oxidative Stress in Trypanosoma cruzi. R. MARTÍNEZESPINOSA*, I. MARTÍNEZ and B. ESPINOZA, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
Trypanosoma cruzi, the causative agent of Chagas disease in America, is constantly exposed to reactive
oxygen species (ROS) generated either by endogenous processes or by external influences, such as
immune responses and drug metabolism. These toxic species generate oxidative stress that can damage
important proteins by processes like carbonylation, in which proteins function is inhibited and can form
cytotoxic aggregates. Some proteins are more susceptibles than others. In the case of T. cruzi, there are
no reports about the pattern of proteins that are mainly carbonylated under oxidative stress. Also, it has
been proposed that this parasite is very sensitive to oxidative damage induced by ROS. To investigate the
amount and pattern of proteins that were the target of oxidative damage, carbonyls were derivatized with
2,4-dinitrophenylhydrazine, separated by SDS-PAGE and the product was detected by western blot
analysis in both control and hydrogen peroxide exposed samples of three Mexican strains of T. cruzi
epimastigotes. At the same time, we evaluated the expression of HSP70 whose relevance under oxidative
stress is well-known, as well as its susceptibility to be carbonylated. The overall level of protein carbonylation increased in the samples exposed to hydrogen peroxide and showed differences between strains.
The proteins affected correspond to molecular masses of approximate 115, 95, 75, 60, 53 and 45 kDa.
On the other hand, densitometric analysis showed that the expression of HSP70 diminished when
parasites were exposed to hydrogen peroxide. Differences between strains in mobility and growth
capacity after hydrogen peroxide challenge were detected.
40
Characterization and Evaluation of an Antigenic Extract for Diagnosis of Trypanosoma cruzi Infection in
Sera by Elisa Assay. Preliminary Results. M.I. BUCIO-TORRES, Departamento de Microbiología y
Parasitología, Facultad de Medicina, UNAM, México DF, E. TORRES-GUTIÉRREZ, E. AMADORGAYTÁN *, M. CABRERA-BRAVO, A.L. RUIZ-HERNÁNDEZ, Y. GUEVARA-GÓMEZ, L. RUIZGONZÁLEZ, J. ROJO-MEDINA, G.S. GARCÍA-DE LA TORRE, L. GONZÁLEZ-LÓPEZ, G.E. ROJASWASTAVINO, M.O. VENCES-BLANCO, M. GUTIÉRREZ-QUIRÓZ and P.M.S. SALAZAR-SCHETTINO,
Medicina, UNAM, México DF, México.
Different serological tests have been used to diagnose Chagas disease in indeterminate and chronic phase;
OPS/OMS recommended the use of IFI, HAI and ELISA. In México, commercial tests are very expensive, and for this reason they are not used routinely for laboratory diagnosis. The aim of this research was
to obtain a low-cost Mexican antigenic reactive to be used in the diagnostic centers in our country. The
antigenic extract was obtained by sonication from three different strains of Trypanosoma cruzi that were
characterizations by total protein quantification, electrophoretic pattern (SDS-PAGE) and reactivity in
Western-blot. The evaluation was by ELISA test and sensitivity, specificity, positive and negative predictive values were determined by comparison between our antigenic extract and a commercial reagent
(Chagatek ELISA). We analyzed 100 samples (50 reactives and 50 non-reactives). The protein concentration was 4.95 mg/ml, the electrophoretic pattern showed components in a range between 10 and 166
kDa, and antigenic extract showed reactivity with a reference serum. The sensitivity was 100%, specificity 98%, and positive and negative predictive values were 100% and 98%, respectively. These preliminary
results give us the possibility of using this extract for serodiagnosis of Trypanosoma cruzi infection.
41
Cloning and Purification of a Protein Phosphatase 2C From Leishmania mexicana. A. NAVARRETEMENA*, Departamento de Medicina Experimental, Facultad de Medicina, UNAM, México DF, México,
N. CABRERA-GONZÁLEZ, R. PÉREZ-MONTFORT, Departamento de Bioquimica, Instituto de Fisiologia Celular, UNAM, I.D. BECKER and M.M. AGUIRRE-GARCÍA, Departamento de Medicina Experimental, Facultad de Medicina, UNAM, México DF, México.
Parasitic protozoa of the genus Leishmania cycle between two main developmental stages: the promastigotes in the digestive tract of the sandfly and the amastigotes in the mononuclear cells of the mammalian host. In higher eukaryotes, the reversible phosphorylation of proteins on serine, threonine, and
71
ABSTRACTS
tyrosine plays a key role in the integration of the signals involved in cellular proliferation and differentiation. In Leishmania, several protein kinases have been cloned and characterized. However, information
about protein phosphatases and their function is limited. Ser/Thr protein phosphatases are divided into
two distinct families: the phosphoprotein phosphatases (PPPs) and the Mg+2 or Mn+2 dependent protein
phosphatases (PPMs). The PPP family is divided into three distinct subfamilies (protein phosphatases 1,
2A and 2B) and the PPM family consists only of protein phosphatases 2C (PP2Cs). In parasites such as
Trypanosoma brucei and Toxoplasma gondii, two protein phosphatase have been cloned and the expression
of the gene and protein product have been analyzed. In Plasmodium falciparum, the presence of a protein
phosphatase (PP1) is relevant in the release of merozoites. In this work, we show that Leishmania
mexicana possesses a protein phosphatase. A gene for PP2C of L. mexicana was amplified by PCR using
the specific oligonucleotides of PP2C of L. major. The optimum conditions for protein expression were
2 h at 37oC in the bacterial strain Rosetta-gami. The recombinant protein was purified by niquelcolumn and eluted with imidazole gradient. This enzyme showed a molecular weight of 44.9 kDa and
dephosphorylated the substrates: pNPP and serine/threonine peptides. The analysis the participation of
L. mexicana PP2C in the regulation of cellular proliferation of this parasites and possibly mechanism to
control the disease represents an interesting in the study of Leishmania evasion. (This work was supported by grants IN221606 from DGAPA and 45052-M from CONACyT México.)
42
Mechanisms of Action of Dehydroepiandrosterone on Entamoeba histolytica. C. CERVANTESREBOLLEDO*, Departmento de Immunología, Instituto de Investigaciones Biomédicas, UNAM,
México DF, E. SAAVEDRA-LIRA, Departmento de Bioquímica, Instituto Nacional de Cardiologìa,
México DF, M. NEQUIZ, Departmento de Medinica Experimental, Facultad de Medicina, UNAM,
México DF, J.P. LACLETTE, Departmento de Immunología, Instituto de Investigaciones Biomédicas,
UNAM, México DF, and J.C. CARRERO-SÁNCHEZ, Departmento de Immunología, Instituto de
Investigaciones Biomédicas, UNAM, México DF.
Dehydroepiandrosterone (DHEA) and its ester sulphate (DHEA-S) are the more abundant steroids
hormones secreted by the adrenal gland. Our previous studies demonstrated that DHEA inhibits the in
vitro proliferation of Entamoeba histolytica trophozoítes. The anti-amebic effect of DHEA is of great
interest due to the serious problems of public health caused by this parasite and the lack of antecedents
about the hormones effect on the amebic infection. It has been reported that the anti-proliferative effect
of DHEA on human cancer cell lines is due to the inhibition of the enzyme 3-hydroxy-3-methylglutarylCoA reductase (HMGR). In view of this, we evaluated the effect of DHEA on a putative HMGR
activity detected in clarified extracts from E. histolytica trophozoites. The addition of DHEA to the
enzymatic reaction at different concentrations inhibited the activity of this enzyme in a dose-dependent
manner, obtaining an IC50 of 0,089 mM. The possibility that DHEA might interact with an androgen
receptor, and in this way affect the proliferation of the amoeba, also was evaluated through the use of a
compound lacking steroid activity that inhibits the binding of the androgen to its receptor. Assays
showed that the treatment of ameba cultures with 1 and 5 ug/ml of flutamide during 2 and 4 h reverted
the anti-proliferative effect of DHEA (1 and 5 ug/ml). Moreover, binding of tritiated-DHEA to fixed
and non-fixed trophozoites, as well as to some bands in different amebic fractions (Alley technique), also
were observed. In conclusion, our results suggest that DHEA inhibits the in vitro growth of E. histolytica
trophozoites by inhibiting its HMGR-like activity, rate-limiting enzyme in the biosynthesis of mevalonic
acid, a precursor of the cholesterol, necessary for cellular duplication, or/and by binding to an androgenreceptor type molecule, which activates nuclear factors that affect the proliferation of E. histolytica.
43
Identification of Surface Proteins of Trypomastigotes of Mexican Strains of Trypanosoma cruzi. M.
MARTÍNEZ-VELASCO*, Departamento de Inmunología, Instituto de Investigaciones Biomédicas,
UNAM, México DF, H. LANZ-MENDOZA, G. HURTADO, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelo, México, and B.
ESPINOZA-GUTIÉRREZ, Departamento de Inmunología, Instituto de Investigaciones Biomédicas,
UNAM, México DF.
72
ABSTRACTS
Trypanosoma cruzi is the causative parasite of Chagas disease, which presents genetic heterogeneity that is
reflected in variability in his biological properties. The Mexican strains of T. cruzi have been classified as
genotype I. Previous results with two Mexican strains concluded that they presented different infectivity
and virulence capacities. In this work the trypomastigotes surface proteins of two Mexican strains were
studied and identified. The parasite surface proteins were labeled with biotin, purified by avidin affinity
chromatography and analyzed by two-dimensional electrophoresis. Some purified surface proteins were
identified by MALDI-TOF. The results showed abundant proteins with acid pI minor to six. An organization in protein groups with very similar molecular weight and pI suggested that they could be isoforms
or families of proteins. Finally, purified surface protein identification was realized in both strains.
MALDI-TOF analysis showed the presence of one Mucins Associated Surface Protein (MASP) and one
gp63, proteins recently described in the genome of this parasite and proposed as possible virulence
factors. Besides, other surface proteins such as three transialidases, one gp82 and three different HSP
were identified. These results can contribute to the better understanding of the complexity of the surface
coat of this parasite.
44
Distribution of Cytoskeletal Proteins in Flame Cells of Taenia solium Cysticerci. L.E. VALVERDE-ISLAS*,
O.A. REYNOSO-DUCOING, Departamento de Microbiología y Parasitología, Facultad de Medicina,
UNAM, E. VEGA-MUNGUÍA, Departamento de Visualización, DGSCA, UNAM, México DF, and J.R.
AMBROSIO HERNÁNDEZ, Departamento de Microbiología y Parasitología, Facultad de Medicina,
UNAM, México DF, México.
It is known that tapeworms contain an osmotic regulatory and excretory system composed of an extremely complex system of ducts with tubules that end in flame cells (FC) and these tubules are connected to collecting ducts. FC are characterized by a large body and a tuft of cilia, the “flame,” which can
be observed beating rapidly under the light microscope. At ultrastructural level, each cilium consists of
the typical 9+2 pattern of microtubules. Until now, there were no studies that demonstrated if the FC
architecture is related to excretory functions. Using immunohistochemistry strategies for platyhelminthes
S. mansoni and D. dendriticum, some information was obtained regarding the distribution of some
cytoskeletal proteins as myosin II and actin. The aim of the present studies was to demonstrate how
monoclonal and polyclonal antibodies, raised against cytoskeleton proteins, can be useful for establishing
the distribution of cytoskeletal proteins in FC of T. solium cysticerci; muscular myosin II, F-Actin, α- and
γ-tubulins were studied using confocal laser scanning microscopy (CLSM) and transmission electronic
microscopy (TEM). Z Images recovered from CLSM were processed for 3D reconstructions with the
computer-based software Amira 3.1 and the produced images were animated. The results demonstrate
how FC are distributed in cysticerci, the cellular distribution of α- and γ-tubulins and F-Actin in these
cells, and how these FC are supported by muscular contractile proteins in parasite tissues. Integrations of
images from CLSM and TEM could indicate how FC are participating in excretory activities in T. solium
cysticerci. (Work supported by CONACYT-México [43629] and DGAPA-UNAM [IN 201003 and IN
216107].)
45
EhADH Is an Entamoeba histolytica Surface Bro1 Domain-containing Protein Involved in Vesicle
Biogenesis. C. BAÑUELOS*, G. GARCÍA-RIVERA, I. LÓPEZ-REYES, S. CASTELLANOS-CASTRO,
Departamento de Patología Experimental, CINVESTAV-IPN, México DF, México, L. MENDOZA,
Posgrado en Ciencias Genómicas, UACM, México DF, México, A. GONZÁLEZ-ROBLES, and E.
OROZCO, Departamento de Patología Experimental, CINVESTAV-IPN, México DF, México.
EhADH is a part of the Entamoeba histolytica EhCPADH complex, and is a key player in the parasite’s
virulence. EhADH has a Bro1 domain at its N-terminus. Bro1 domain-containing proteins have been
involved in a broad spectrum of cellular functions, including multivesicular bodies (MVB) formation.
Here, we studied the EhADH protein and the EhADH-Bro1 domain functions, including their contribution to endocytosis and phagocytosis. ANeoBRO trophozoites, which overexpress the first 166
EhADH amino acids (EhADH-Bro1 domain), were dominant negative for phagocytosis in comparison
with ANeo wild-type trophozoites. Through confocal microscopy, EhADH was detected in the trophozoite plasma membrane and in cytoplasmic vacuoles, whereas the EhADH-Bro1 protein (BRO-FLAG)
73
ABSTRACTS
was accumulated in vesicles. Ultrastructural studies showed EhADH in plasma membrane, endosomes,
vacuoles, fusing vesicles, MVB and lysosomes. During erythrophagocytosis, EhADH appeared in
phagosomes, RBC and MVB. In contrast, BRO-FLAG was located in huge vesicles, without reaching
the plasma membrane. During erythrophagocytosis, we rarely found BRO-FLAG molecules within
phagosomes. By subcellular fractioning, endogenous EhADH and BRO-FLAG were located in soluble
and membrane fractions. Both proteins seem to associate to different molecules that form complexes
probably involved in the MVB pathway. Our findings define EhADH as a member of a novel subfamily
of Bro1 domain-containing proteins present at the cellular surface. Through its Bro1 domain, EhADH
could be participating in endosomal trafficking and protein sorting.
46
Trichinella spiralis Oocyte Maturation Is Inhibited by Cyclosporin A in Rats Infected with this Parasite.
R. HERNÁNDEZ-BELLO*, Departamento de Genética y Biología Molecular, CINVESTAV, México DF,
R.M. BERMÚDEZ-CRUZ and R. FONSECA-LIÑÁN, Departamento de Genética y Biología Molecular,
CINVESTAV, México DF, México, P. GARCÍA-REYNA, Facultad de Veterinaria, UAEH, Pachuca, Hidalgo,
P. BOIREAU, UMR, BIPAR, Maisons-Alfort, France, and G.M. ORTEGA-PIERRES, Departamento de
Genética y Biología Molecular, CINVESTAV, México DF, México.
Cyclosporin A (CsA), a potent immunosuppressive drug, has been used as anti-parasitic drug against a
variety of helminths. In previous studies on the effect of CsA in mice treated with this drug during T.
spiralis infection, a total absence of new-born larva (NBL) deposition by female worms obtained from
these animals was observed. This correlated with the lack of larval development in uterus. Based on this
and on recent observations by our group on the role of caveolin-1 of T. spiralis (CavTs) in oocyte maturation in female worms, we studied the effect of CsA in the oogenesis of T. spiralis using CavTs protein as a
marker of oocyte maturation. This was approached using light microscopy, immunohistochemical
techniques with anti-CavTs antibodies together with confocal laser microscopy. Observation in light
microscopy of parasites obtained at day 1 post-infection (pi) from untreated and CsA treated rats did not
shown differences in oocytes maturation. However, parasites obtained at 2 and 3 days pi from untreated
rats showed mature and fertilized oocytes, respectively. In contrast, parasites from CsA treated rats
showed only immature oocytes. Female parasites obtained at 5 days pi from untreated rats contained
fully developed NBL in uterus, while females from CsA treated rats contained only immature oocytes.
Confocal analysis of cross-sections of female worms from untreated rats using anti-CavTs antibodies
showed that CavTs is accumulated in the oocyte membrane until fertilization occurs. Similar analysis of
female worms from CsA treated rats obtained at 1 to 5 days pi showed a lower CavTs expression in the
immature oocytes with irregular membrane localization. These results suggest that CsA may prevent the
correct membrane localization and function of CavTs in oocyte maturation, probably by depleting cholesterol from the oocyte membrane, as has been shown in other cell systems.
47
Leishmania mexicana-specific Antigens for Serologic Diagnosis. N. ROBLES-BRIONES*, A. RUIZREMIGIO and I.D. BECKER, Departamento de Medicina Experimental, Facultad de Medicina, UNAM,
México DF, México.
In México, leishmaniasis is caused by Leishmania mexicana, which can cause localized (LCL) and diffuse
(DCL) cutaneous leishmanaisis. The disease is present in the same ecological habitat as Trypanosoma cruzi
and immunological cross-reactions occur between both parasites, making a specific serological diagnosis
difficult. In the current project we developed a Leishmania-specific serological diagnosis with identification of antigens that do not cross-react with T. cruzi antigens. Material and Methods: A Western-blot
analysis using protein extracts from both parasites was made with serum from patients with Chagas
disease and patients with LCL and DCL. The proteins were visualized with alkaline phosphatase.
Results: We found that the sera from the three groups of patients recognized many proteins present in
both parasites, yet we also identified a 39 kDa L.mexicana specific protein that was recognized by sera
from LCL and DCL patients. Additionally, we identified L.mexicana proteins that were only recognized
by DCL patients (18.5, 17.5, 11 and 8 kDa). These proteins were considered Leishmania specific, since
they were not recognized by sera of patients with Chagas disease. It is noteworthy that this study
identified proteins that were only recognized by DCL patients, thus providing a specific diagnostic tool
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ABSTRACTS
that permits the discrimination between LCL and DCL patients. This finding will help optimize serological diagnosis of leishmaniasis and Chagas disease and thereby improve treatment designs for patients
with LCL, DCL and Chagas disease. (Grants: CONACyT: 47256 and DGAPA: 221806-3.)
48
In vivo Efficacy of Nitazoxanide Against Toxoplasma gondii. M. GALVÁN-RAMÍREZ, G. SÁNCHEZ
GONZÁLEZ *, L.R. RODRÍGUEZ PÉREZ, Departamento de Fisiología, Centro Universitario de Ciencias
de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco, R.A. FRANCO TOPETE, Departamento
de Patología del Nuevo Hospital Civil de Guadalajara, and M.A. RAMIREZ HERRERA, Departamento
de Fisiología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara,
Jalisco, México.
Background: Nitazoxanide (NTZ 2-acetolyloxil-N-5-nitro-2-thiazoly benzamide) has shown effectiveness
at about 85% to 97% in the treatment of intestinal parasites. Pyrimethamine (PYR) is the drug widely
used in toxoplasmosis treatment; nevertheless, it presents collateral effects in patients by decreasing folic
acid. Objective: The purpose of this study was to evaluate the in vivo efficacy of NTZ in Swiss mice
infected with T. gondii Rh strain tachyzoites. Methods: Three groups of Swiss mice were studied, with
each group of 12 mice infected with 2 x 103 tachyzoites of T. gondii. Group 1 was treated with 10, 25,
50, 75 or 100 mg/Kg of NTZ; Group 2 was treated with 12.5, 25, 50, 75 or 100 mg/Kg of PYR;
Group 3 (control) was treated with 500 µl of sterile phosphate-buffered saline (0.01 M pH 7.4 and
DMSO al 0.25% ). Each drug was dissolved in 500 µl solution group control. After 10 days of treatment
or when the mice died, the tachyzoites were counted in a Neubauer chamber and the survival rate was
observed. To study NTZ and PYR toxicity, two groups of 12 mice were treated with 100 mg/Kg of
NTZ. The mice brains were stained with hematoxilin and eosin. Group 4 was treated with 100 mg/Kg of
NTZ, and Group 5 was treated with 100 mg/Kg of PYR. This treatment was given for 10 days to assay
toxicity, and mice were sacrified. Results: The efficacy of NTZ with the 75 and 100 mg/Kg dose was
similar to that of PYR, and a higher survival rate was observed with the 25 to 100 mg/Kg NTZ dose
than with PYR. The 100 mg/Kg dose of PYR was toxic as was shown by piloerection and death. Following PYR treatment, weight loss was considerable and moderate lethargy was observed; with NTZ, there
was slight weight loss, which was gained immediately. Conclusions: NTZ effectively reduced the number
of T. gondii Rh strain tachyzoites and showed increased survival rate in infected mice. NTZ shows less
toxicity and fewer side effects. NTZ can be a useful drug for the treatment of toxoplasmosis without
severe side effects.
49
Proteomical Evaluation of New Potential Benzimidazole Derivatives Against Giardia intestinalis. C.A.
MÉNDEZ-CUESTA*, L. VELÁZQUEZ-MÁRQUEZ, Departamento de Microbiología y Parasitología,
Facultad de Medicina, UNAM, M.A. DEA-AYUELA, Departamento de Parasitología, Facultad de
Farmacia, Universidad Complutense de Madrid, Madrid, España, R. CASTILLO-BOCANEGRA, F.
HERNÁNDEZ-LUIS, M.A. HERNÁNDEZ-CAMPOS, Departamento de Farmacia, Facultad de Química,
UNAM, L. YÉPEZ-MULIA, UIMEI, Centro Médico Nacional Siglo XXI, IMSS, México DF, F. BOLÁSFERNÁNDEZ, Departamento de Parasitología, Facultad de Farmacia, Universidad Complutense de
Madrid, Madrid, España, O.A. REYNOSO-DUCOING and J.R. AMBROSIO-HERNÁNDEZ, Departamento de Microbiología y Parasitología, Facultad de Medicina, UNAM, México.
The drug of choice for the treatment of giardiasis has been metronidazole (MTZ) and nitazoxanide
(NTZ). Recently, it has been shown that albendazole (ABZ) has giardicidal activity due to the inhibition
of the polymerization of tubulin. In recent years, however, resistance to MTZ and ABZ has been developed by the parasites, in clinic trails and in vitro. As part of our efforts to find new giardicidal compounds, a series of 2-(methylthio)- N-(1,3-thiazol-2-yl)-1H-benzimidazole-5-carboxamide derivatives
were synthesized and tested in vitro against G. intestinalis. One of them is compound CMC-20. Another
compound, RSD-8, was designed and synthesized to learn the importance of the hydrogen at position 1
on the antiprotozoal activity. In the present study, a proteomic assay was carried out on the in vitro effect
of CMC-20 and RSD-8, as well as MTZ, NTZ and ABZ, on giardia. Following drug treatment, the
trophozoites were submitted to thaw–freeze cycles, and the product was used for the analysis. 1D
electrophoresis was carried out in 18 cm immobilized pH 4-7 gradient strips. For 2D electrophoresis,
75
ABSTRACTS
samples were separated onto 12.5% SDS-PAGE gels and proteins were visualized by colloidal
Coomassie. Approximately 200 spots were resolved in each treated and untreated samples, and some of
them were excised for mass spectrometry analysis (MALDI-TOF). Analysis revealed an increase or
decrease in the expression of some proteins that could be identified. SALP-1 and thioredoxin–peroxidase
increased in MTZ, NTZ and ABZ treated samples compared to control samples. CMC-20, RSD-8 and
NTZ reduced the expression of giardins, arginine deiminase and UPL-1. Giardins and the axonemeassociated protein are a group of cytoskeletal proteins that, together with tubulins, are the main components of ventral disk and flagella. These variations on protein expression correlated with observations
performed by Scanning Electronic Microscopy (SEM). These approaches could be useful for evaluating
the action of drugs and also they can be a good chance for learning what kind of proteins are involved.
(This work was supported by Conacyt-México 43629, DGAPA-UNAM IN201003, IN216107.)
50
In vitro Anthelmintic Activity of Plant Extracts from Tropical Tanniniferous Trees Against Trichostrongylus
colubriformis. M.A. ALONSO-DÍAZ*, CEIEGT-FMVZ, UNAM, Martínez de la Torre, Veracruz, México,
J.F. TORRES-ACOSTA, C.A. SANDOVAL-CASTRO, A.J. AGUILAR-CABALLERO, FMVZ, Universidad
Autónoma de Yucatán, Mérida, Yucatán, México, and H. HOSTE, Ecole Nationale Vétérinaire Toulouse, Toulouse, France.
As for temperate foragers, some tropical tannin-rich plants from browsing might be an alternative to
chemical anthelmintics. Recent studies have shown that extracts from leaves of tropical legume trees have
an in vitro anthelmintic (AH) effect against Haemonchus contortus. It is important to assess whether these
effects depends on the nematode species. Extracts of four tanniniferous plants (Acacia pennatula, Lisyloma
latisiliquum, Piscidia piscipula, Leucaena leucocephala) were tested against Trichostrongylus colubriformis
using two in vitro assays. First, the effects of increasing concentrations of lyophilized extracts (150, 300,
600, 1200 µg/ml PBS) were tested on T. colubriformis larvae using the Larval Migration Inhibition (LMI)
test. Levamisole and PBS were used, respectively, as positive and negative controls. An inhibitor of
tannin, PVPP, was used to verify whether tannins were responsible of the effects. Second, the effects of
extracts on larval exsheathment were examined. After a three-hour contact with extracts (1200 µg/ml);
the larvae were exposed to an artificial exsheathment procedure, with observation of the process at 10minute intervals. A GLM test was used to determine the dose effect in the LMI test. A Kruskal-Wallis
test was used to determine the effect of PVPP on LMI results. No anthelmintic effect was found for P.
piscipula, but the LMI test showed a dose-dependent effect for the three other plants (P < 0.001). PVPP
confirmed the role of tannins in the observed effects. All four plant extracts interfered with the process of
L3 exsheathment, which might be involved as a mechanism of action of CT on T. colubriformis larvae.
(This trial was funded by CONACYT-SAGARPA-COFUPRO [project no. 12441] and the ECOSFrance/ANUIES-CONACYT-México [project no. M03A03].)
51
Variation in the P-glycoprotein (PgP) Gene from Onchocerca volvulus Mexican Isolates. S. GONZÁLEZGUZMÁN*, Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, IPN, México DF,
G. SÁNCHEZ-TEJEDA, J. MÉNDEZ-GALVAN, Centro Nacional de Vigilancia Epidemiológica, Secretaria
de Salud México, and A. MONROY-OSTRIA, Departamento de Inmunología, ENCB, IPN, México DF,
México.
Onchocerca volvulus is a filarial nematode transmitted by Simulium spp. black flies in endemic regions of
Africa and South America. Clinical disease can result from an inflammatory response to the microfilariae
(mf) in the skin and the eyes, progressing in some cases to blindness. Ivermectin is the selected drug for
treatment of onchocerciasis and is administrated to the population at risk. Ivermectin reduces parasite mf
counts in the skin and reduces the fecundity of the surviving female parasite. In other nematodes,
parasites have demonstrated resistance to ivermectin mediated mainly by phosphoglycoproteins (PgP).
In this study, the PgP gene of several Mexican samples (onchocercomata) from Chiapas and Oaxaca
endemic states from México was amplified by the Polimerase Chain Reaction (PCR) with the specific
primers OVPL1 and OVPL2 (generated from sequences from African O. volulus). The amplicons were
cloned with TA Cloning (pCRR II Vector) (Invitrogen, USA) and transformed into E. coli INV αF´ and
sequenced using the kit (ABI PRISM Dye Terminator Cyclers Secuencing Ready Reaction Kit, Perkin
76
ABSTRACTS
Elmer) and an automated sequencer Abi Prism M 310 Genetic Analizer, Perkin Elmer. The sequences
were edited with DNAMAN; Chromas Ver. 2.0 and Seaview. Multiple sequence alignment was carried
out using Clustal-X Ver. 1.83. Phylogenetic trees were constructed by the neighbour-joining method.
Evolutionary distances were calculated using a Kimura’s two-parameter method with MEGA Ver. 3.1.
program. Sequences data were compared with previously published sequences of Pgp of O. volvulus. Only
14 out of 64 samples were amplified with OVPL1 and OVPL2 primers; with the sequences of Mexican
samples, a couple of primers were designed to amplify more samples. The phylogentic tree shows that
the samples from Chiapas are placed in the same group, except one sample, which was placed alone in a
group apart. Samples from Oaxaca formed another group. (A. Monroy-Ostria is supported by COFAA
and EDI, IPN, México; S. González-Guzmán was sponsored by CONACyT, México.)
52
Communities of Helminth Parasites of Bufo marinus (Linnaeus, 1758) and Bufo valliceps (Wiegmann,
1833) (Anura: Bufonidae) in the Lagunas de Yalahau, Yucatán. J.F. ESPINOLA-NOVELO*, Campus de
Ciencias Biologicas y Agropecuarias, Depto. Biología Marina, and S. GUILLÉN-HERNÁNDEZ, Campus
de Ciencias Biologicas y Agropecuarias, Depto. Biología Marina, Universidad Autónoma de Yucatán.
Most studies on helminth communities of amphibians have been done mainly in the Nearctic regions of
America. There are few works related to the helminth fauna of this group of vertebrates in México. In the
Yucatán Peninsula, reports of parasitic helminths of some amphibians have been done, but none has been
done to the community level. In this work, the helminth communities of Bufo marinus and Bufo valliceps
(Anura: Bufonidae) from Lagunas de Yalahau are described. The analysis was conducted at community
and infracommnity levels. A total of 80 hosts were collected: B. marinus (N = 40) and B. valliceps (N =
40). Seven different helminth species were found: one digenean, Langeronia macrocirra, one acantochephalan (Cystacant), and five nematodes, Rhabdias fulleborni, Aplectana sp, Cruzia morleyi, Ozwaldocruzia
sp. and one in the larvae stage. Six species were present in B. marinus and four in B. valliceps. Two species
are reported for the first time in B. valliceps and three are first records for the Yucatán State. Diversity and
dominance values showed departure and dominated communities. The dominating species was Aplectan
sp. in both communities. This pattern was observed in host species at component and infracommunity
levels.
53
Behavioral Disruption on Fiddler Crab, Uca speciosa (Ives, 1891), Caused by Hexaglandula corynosoma
(Travassos, 1915) in the Chuburná Lagoon, Northern Yucatán Peninsula: A Progress Report. R.A.
PÉREZ-CAMPOS* and S. GUILLÉN-HERNÁNDEZ, Laboratorio de Biología Marina, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán.
Many studies have demonstrated that parasites can manipulate specific aspects of the behavior of their
hosts to ensure their permanence in the environment. Hexaglandula corynosoma is an acanthocephalan
parasite very common in crabs of the species Uca speciosa from northern Yucatán Peninsula. It is known
that acanthocephalan parasites are able to disrupt the behavior of their host by increasing probabilities of
predation on its definitive host by seabirds. Nevertheless, studies on this topic have not been reported for
México. From September 2006 to February 2007, monthly collections were made in two localities of the
lagoon system of Chuburná, Yucatán. In those collections, crabs were separated as (1) inside burrows
and (2) outside. A total of 303 individuals was examined, 153 outside and 150 inside. The values of
prevalence, mean intensity, and mean abundance of parasites in crabs outside burrows were higher
compared with those inside. Parasites in these latter were in an earlier stage of development compared
with those parasites in crabs outside. This suggests that parasite presence is potentially causing a disruption in the behavior of the crabs, making these latter to remain outside burrows, consequently making
them more vulnerable to predation by seabirds.
54
Preliminary Report of the Genetic Typing of Echinococcus granulosus in México. D.E. JIMÉNEZGONZÁLEZ*, Departamento de Ecologia de Agentes Patogenos, Hospital General “Dr. Manuel Gea
González,” SSA, México DF, U. RODRÍGUEZ-PRADO, Facultad de Medicina Veterinaria y Zootecnia,
UNAM, México DF, A. LÓPEZ-SAAVEDRA, L. HERRERA, Instituto de Investigaciones Biomedicas,
77
ABSTRACTS
UNAM, México DF, C. MONDRAGON, Universidad de Zacatecas, Zacatecas, Zac, P. MATA, Departamento de Ecologia de Agentes Patogenos, Hospital General “Dr. Manuel Gea González,” SSA, México
DF, A. FLISSER, Departamento de Microbiologia y Parasitologia, Facultad de Medicina, UNAM, México
DF, J.J. MARTÍNEZ-MAYA, Facultad de Medicina Veterinaria y Zootecnia, UNAM, México DF, and P.J.
MARAVILLA-CAMPILLO, Departamento de Ecologia de Agentes Patogenos, Hospital General “Dr.
Manuel Gea González,” SSA, México, México DF.
Little is the known about Echinococcus granulosus strains in México. There are a few reports suggesting
the existence of the G7 swine strain; however, a recent publication described an autochthonous case of
cystic echinococcosis in a woman who had the bovine G5 strain, demonstrating the existence of more
than one strain in our country. The objective of our work was to perform genetic typing of E. granulosus
strains according to the cytochrome c oxidase subunit 1(COI) sequences of swine and sheep from rural
areas in Central México. The parasites were identified in vivo by ultrasonography of sheep abdomens or
by visual inspection of the viscera during necropsy in rural slaughterhouses. No hydatid cysts were found
in sheep. Cysts from 10 infected pigs were collected in the states of Aguascalientes (2), Morelos (1) and
Zacatecas (7). For molecular analysis, cyst fluid was centrifuged and hydatid sand was incubated with
proteinase K overnight at 53ºC. DNA was purified by the phenol-chloroform conventional method.
PCR was performed with primers COI-F 5´TTTTTTGGGCATCCTGAGGTTTAAT and COI-R
5´TAAAGAAAGAACATAATGAAAAT. Thermocycler conditions were as follows: initial denaturation
of 94°C for 2 min, 54°C annealing for 1 min, 72°C extension for 1 min; 35 cycles of 94°C for 30 s, 54°C
for 30 s, 72°C for 30 s; and a final extension at 72°C for 7 min and hold at 15°C. PCR products were
visualized using ethidium bromide in 1% agarose gel after electrophoresis for 60 min at 70V. Amplicons
of 444 pb were obtained from all hydatid cysts, which were purified and sequenced. Sequence results
were analyzed using ChromasPro version1.33 software and aligned using Clustal W software. All the
studied cysts had 95–97% identity with the G7 Echinococcus granulosus strain, confirming the higher
frequency of the swine strain and host in México and supporting the low frequency of the human disease
since the swine strain seemed to be poorly infective for humans, although it is apparent that infection
with this strain does occur.
55
Diagnosis of Lymnaea Snail Infection by Fasciola hepatica Using Duplex-PCR. C.P. RICO-TORRES*,
Instituto Nacional de Pediatría, SSA, México DF, I. CRUZ-MENDOZA, H. QUIROZ-ROMERO, FMVZ,
UNAM, L.B. ORTÍZ-ALEGRÍA and D. CORREA, Instituto Nacional de Pediatría, SSA, México DF,
México.
Fasciola hepatica, the common bile duct fluke, is widely distributed in temperate and subtropical areas
around the world, infecting numerous species of mammals as definitive hosts and various species of snails
of the genum Lymnaea, Pseudosuccinea and Stagnicola. Lymnaeid species that commonly harbor the
parasite in México include L. humilis and L. bulimoides. Traditional methods for F. hepatica detection are
based on snail exposure to light, in order to induce cercarial release or by dissection and search of
sporocysts, rediae or cercariae. Such methods are of low sensitivity, compromising field trials. Molecular
techniques such as multiplex PCR have been used extensively as diagnosis tools. In this work, the
presence of F. hepatica in L. humilis and L. bulimoides was detected at different times of infection by
Duplex-PCR. A PCR assay was standardized using a primer pair that amplifies the 28S rRNA. A 618 bp
product was observed using genomic DNA of adults and eggs of the trematode, but two amplicons of
618 and 500 bp were amplified from snail DNA. Therefore, this PCR reaction was used as an internal
control, and another primer pair that amplifies a region of 405 bp of the F. hepatica cytochrome c oxidase
subunit 1 gene was tested. L. humilis and L. bulimoides were infected with two recently hatched miracidia,
and DNA was extracted at 0, 4, 24 and 72 hours to perform a duplex PCR. Parasite infection of snails
was detected after four hours of infection, as shown by appearance of the three expected bands. The use
of this PCR may help F. hepatica detection in snail populations, providing information on pasture
contamination, an important issue concerning livestock fasciolosis control.
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ABSTRACTS
56
Trypanosoma cruzi sHSP16: The First Member of the Alpha-crystallin-small Heat Shock Protein Family
in Trypanosomatids. D. PÉREZ-MORALES*, P. OSTOA-SALOMA and B. ESPINOZA, Departamento de
Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
Trypanosoma cruzi is a parasite responsible for Chagas disease. As with many parasites, T. cruzi is exposed
to dramatic temperature changes throughout its complex life cycle. Adaptation to these temperature
variations is crucial for the parasite’s survival, reproduction and therefore transmission. These conditions
may increase the synthesis of a set of proteins commonly known as heat shock proteins (HSPs). The
small heat shock proteins (sHSPs) are one of the four most common groups of the HSPs and some of
them are evolutionary related to the vertebrate lens protein α-crystallin. This work describes for the first
time the identification and characterization of a sHSP from T. cruzi. The nucleotide sequence of this
gene was determined by a heterologue search on the T. cruzi genome. The newly identified 16 kDa
protein was shown to posses the characteristic α-crystallin domain, hence it is named SHSP16 and
categorized as a new member of the α-crystallin-sHSP family. We identified putative heat-shock factor
binding sites upstream of the SHSP16 translation start site. To investigate its gene expression, we
analyzed the corresponding mRNA levels in epimastigote cells heat shocked and demonstrated by semiquantitative RT-PCR analysis that the expression of SHSP16 is heat-inducible, thus demonstrating that it
is a HSP in vivo. Protein extracts from T. cruzi were probed with a anti-SHSP16 polyclonal antibody, and
Western blot analysis showed some bands that migrate more slowly than its expected molecular size and
specifically react with the antibody, probably representing oligomeric forms. We show, in vitro, chaperone-like activity of SHSP16 in preventing thermal aggregation of malate dehydrogenase. The predicted
3D model of SHSP16 was compared with the wheat HSP16.9 monomer, showing that they were
similar. Thus, SHSP16 appears to be a true member of the α-crystallin-sHSP family. These results open
an interesting horizon in the understanding of heat shock response mechanisms on protozoan parasites.
57
Identification of EhBLM, a Putative DNA Helicase in Entamoeba histolytica. M.S. CHARCAS-LÓPEZ*,
Programa Institucional de Biomedicina Molecular, Escuela Nacional de Medicina y Homeopatía-IPN,
México DF, C. LÓPEZ-CAMARILLO, M. LÓPEZ-CASAMICHANA, Posgrado en Ciencias Genómicas,
Universidad Autónoma de la Ciudad de México, México DF, and L.A. MARCHAT, Programa Institucional de Biomedicina Molecular, Escuela Nacional de Medicina y Homeopatía-IPN, México DF,
México.
Double strand break (DSB) of DNA, the most lethal DNA damage, is caused by UV rays, ionizing
radiations or chemical agents. It also occurs in collapsed forks restoration during replication, mitosis and
meiosis. DSB generates mutations, affecting cell functions and survival. Homologous recombination
(HR) is one of the mechanisms involved in DSB repair. Moreover, it allows genetic diversity in meiosis.
HR process involves about 11 proteins, including the Bloom DNA helicase (BLM). BLM belongs to the
RecQ family that catalyzes ATP-dependent DNA unwinding. Four main RecQ homologues have been
described in humans. Mutations in three of them have been associated with cancer and premature death,
indicating their relevance for genomic integrity and cellular viability maintenance. Entamoeba histolytica,
the protozoan responsible for human amebiasis, presents different virulence grades that have been related
with genetic variability. By computational screening of E. histolytica genome, we identified the machinery
involved in HR in this parasite. Particularly, we detected a gene (3549 pb) that codes for a possible DNA
helicase of the RecQ family (EhBLM). The predicted polypeptide (1183 aa) possesses the helicase
domain with the seven motifs that are conserved evolutionary in the RecQ family. The EhBLM helicase
domain was PCR-amplified and cloned into the pRSET-A vector to express the 59 kDa rEhBLM protein
in bacteria, which was recognized by anti-histidine antibodies in Western blot assays. rEhBLM was
submitted to affinity chromatography using Ni-agarose columns to perform functional assays related to
DNA helicases catalytic activities.
58
The ESCRT Machinery of Entamoeba histolytica. I. LÓPEZ-REYES*, C. BAÑUELOS and E. OROZCO,
Departamento de Patología Experimental, CINVESTAV-IPN, México DF, México.
79
ABSTRACTS
The EhCPADH complex is a key molecule in the Entamoeba histolytica virulence. EhCPADH is formed
by a cysteine protease (EhCP112) and an adhesin (EhADH) and participates in trophozoite adherence to
phagocytosis and cytolisis of target cells. EhADH is a surface protein also located in vacuoles that is
translocated during erythrophagocytosis. EhADH is structurally similar to mammalian ALIX and yeast
BRO1 proteins. These proteins have a Bro1 domain at their N-terminal, which is conserved along the
evolutionary scale, and they participate in several processes that include multivesicular bodies (MVB)
formation, apoptosis, virus budding and pH regulation, among others. Bro1 domain-containing proteins
interact with proteins of the Endosomal Sorting Complex Required for Transport (ESCRT) machinery
to perform the sorting and transport of transmembrane proteins through endosomes. In yeast, about 20
proteins named Vacuolar Protein Sorting (Vps) have been involved in the endosomal pathway, being
required for the assembly of ESCRT-0, - I, - II and - III during MVB formation. Nevertheless, in E.
histolytica, we do not know if this biological process occurs through ESCRT proteins. Since E. histolytica
is a highly endocytic organism, even considered a professional phagocyte, we initiated the study of the
protein machinery that orchestrates MVB formation in this parasite. Here, by an in silico analysis, we
showed the presence of yeast or human ESCRT homologues in E. histolytica. Our results showed the
presence of 18 Vps-encoding sequences, possibly involved in MVB formation during the endocytic
pathway of trophozoites. Further studies will determine more precisely the putative interaction of
EhADH with some elements of the ESCRT machinery.
59
Entamoeba histolytica Has the Cleavage Factor EhCF Im25 That Could Be Involved in Pre-mRNA 3' End
Polyadenylation. J. FERNANDEZ-RETANA*, Programa Institucional de Biomedicina Molecular, Escuela
Nacional de Medicina y Homeopatía, IPN, México DF, C. LÓPEZ-CAMARILLO, Posgrado en Ciencias
Genómicas, Universidad de la Ciudad de México, México DF, and L.A. MARCHAT, Programa Institucional de Biomedicina Molecular, Escuela Nacional de Medicina y Homeopatía, IPN, México DF,
México.
In eukaryotes, genetic expression regulation takes place at multiple levels including transcription initiation, elongation and termination. Additional controls points involve transcript translation and degradation. DNA transcription produces immature mRNA (pre-mRNA) that undergoes post-transcriptional
modifications, such as 5' end capping, splicing and 3' end polyadenylation. Pre-mRNA polyadenylation
requires two coupled reactions, cleavage and polyadenylation, in a coordinated way through interaction
with the carboxyl terminal domain of RNA polymerase II. Both processes depend on trans-acting factors
that coordinately interact with specific cis-sequences in 3' UTR to synthesize the poly(A) tail that has
been shown to be essential for mRNA nuclear export, stability and translation efficiency. Recently, we
identified the cleavage and polyadenylation machinery of Entamoeba histolytica, the protozoan parasite
responsible for human amoebiasis. Here we focused on the EhCF Im25 protein, the homologue of the
human CFIm-25 factor that is thought to be involved in RNA 3' end cleavage. Interestingly, E. histolytica
also possesses the EhCF Im-bis gene that seems to result from EhCF Im25 gene duplication associated
with mutations events. In silico analysis showed that EhCF Im25 (31 kDa) shares 28–35% identity with
homologous eukaryotic proteins. Moreover, it has the central NUDIX domain described in distinct
enzymes and a nuclear localization signal. The EhCF Im25 gene was PCR-amplified and cloned into the
pRSET-A vector. The recombinant rEhCF Im25 protein expressed in bacteria was used to generate
specific rabbit antibodies, which recognized a 55 kDa band in nuclear and cytoplasmic extracts of
trophozoites in Western Blot assays. Our results suggested that EhCF Im25 could be interacting with
another protein through a biochemical link that could not be disrupted under reducing and denaturing
electrophoresis conditions.
60
PfSir2 Silencing Complexes Purified by Tandem Affinity Purification from Plasmodium falciparum. N.K.
MITA-MENDOZA*, Departamento de Biomedicina Molecular, CINVESTAV-IPN, México DF, S.
MARTÍNEZ-CALVILLO, Departamento de Biomedicina, Instituto de Investigaciones Biomédicas,
Universidad Nacional Auntóma de México, México DF, and R. HERNÁNDEZ-RIVAS, Departamento de
Biomedicina Molecular, CINVESTAV-IPN, México DF, México.
80
ABSTRACTS
Silent Information Regulator 2 (Sir2) is a histone deacetylase, present in all organisms ranging from
archaea to humans, that has been associated with process of gene regulation. Silencing complexes of Sir2
exist as large assemblies of many different proteins that control gene expresion, rDNA replication and
pairing in Saccharomyces cerevisiae. PfSir2 protein from Plasmodium falciparum was immunolocalized at
telomeres and nucleolar regions, and recently associated with the silencing of var genes located near the
telomeres. Although there are orthologous genes for some silencing-complexes proteins in P. falciparum,
few of them are described. Here we have addressed proteins that are members of PfSir2 native complexes. We obtained transgenic parasites of FCR3 P. falciparum line, which epissomally express a PfSir2
protein that harbor a C-terminal TAP, which consists of a domain of a calmodulin-binding protein, a
TEV protease cleavage site, two protein A domains, and a HA flag. By immunolocalization using HA
antibody, we found that PfSir2-TAPtagHA protein is located at telomeres, nucleolus and citoplasmatic
regions of P. falciparum. Purification of PfSir2-TAPtagHA from crude extracts and SDS-PAGE followed
by Sypro rubi stain show that there are four proteins that could be new members of PfSir2 silencing
complexes.
61
Characterization of the kahrp Gene Core Promoter Region of Plasmodium falciparum. M.E. ARANDABARRADAS* and R. HERNÁNDEZ-RIVAS, Departamento de Biomedicina Molecular, CINVESTAV-IPN,
Ciudad de México DF, México.
RNA pol II promoters in Plasmodium falciparum, as in most of eukaryotic organisms, consist of a core
promoter and upstream regulatory sequences. Some of the cis elements that constitute the eukaryotic
core promoter that have been described in P. falciparum are the initiator and the TATA box. The last one
is located at 81 base pairs upstream of the transcription start site of the kahrp gene; a comparable
location for this element has been described in yeast (yTATA), but not in eukaryotic cells (-30bp). In
higher eukaryotic the general transcription factor TFIIB recognizes the BRE element (TFIIB Recognition Element), which is located adjacent to the TATA box. Recently, by in silico analysis, an orthologous
of TFIIB was identified in the P. falciparum genome (PfTFIIB), and a putative BRE element (PfBRE)
was identified in the promoter region of kahrp gene. Surprisingly, the composition of this sequence is
more similar to that in archaea (aBRE) than the one in eukaryotes (eBRE). These findings suggest that
cis elements that compose the kahrp promoter region of P. falciparum have characteristics of archaeal and
yeast elements. In order to know if the BRE element of P. falciparum is a functional cis element, we
obtained the recombinant protein Maltose-PfTFIIB, which was used to generate antibodies, and finally
supershift assays were performed. This assay shows that PfTFIIB is present in the protein complex that
binds to the promoter region of the kahrp gene. Moreover, by EMSA assays we demonstrated that
Matose- PfTFIIB protein is able to bind specifically to the PfBRE element. Also, we found that this
element can be replaced by eBRE; however, this interaction is less stable than PfBRE-PfTFIIB complex.
62
TLR2 and TLR4 Polymorphisms and Their Relationship to Cutaneous Leishmaniasis. V. BECERRIL*,
UNAM, Departamento de Medicina Experimental, Facultad de Medicina, M. BERZUNZA-CRUZ,
UNAM, Facultad de Medicina, Departamento de Medicina Experimental, G. CARRADA-FIGUEROA,
Universidad Autónoma de Tabasco, Secretaría de Salud Tabasco, M. MALDONADO, Centro Médico
Nacional Siglo XXI, IMSS, and I.D. BECKER, Departamento de Medicina Experimental, Facultad de
Medicina, UNAM.
In leishmaniasis, the innate immune response has been considered decisive in determining the disease
outcome in patients with localized (LCL) and diffuse (DCL) cutaneous leishmaniasis. Toll-like receptors
(TLRs) have been considered to perform a central role in innate response activation in many diseases.
Also in leishmaniasis, TLR2 and TLR4 are considered crucial in the disease outcome, and resistance or
susceptibility has been related to molecular variations in these receptors. The purpose of this study was to
analyze polymorphisms in TLR2 (Arg753Gln) and in TLR4 (Asp299Gly/Thr399lle) in patients with
LCL and DCL, as well as in healthy individuals from the same geographical region, in order to determine if there is a correlation between the polymorphisms and the disease severity. One hundred thirtytwo blood samples were analyzed (62 LCL, 7 DCL, 63 healthy controls). Real-time PCR with allelic
discrimination was done. The results show that 8.5% of the samples showed polymorphisms for TLR4,
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and specifically that Asp299Gly was present in 4.85% of LCL patients and 8.9% of the healthy controls.
The genotypic frequency of polymorphisms in Thr399lle for TLR4 was 5.17% for LCL patients and
14.28% for DCL patients. No TLR2 polymorphism in Arg753 was found in the patients analyzed. No
statistical correlation was found between the polymorphisms in TLR4 and the disease outcome, which
could be due to the small sample size. The fact that only 9.23% of the patients with leishmaniasis had
polymorphisms for TLR4 and none for TLR2 suggests that possibly additional genes are involved in
determining the disease outcome. (Grants: DGAPA: 221806-3 and CONACyT: 47256.)
63
Possible Role of a Putative Glucosamine-6-phosphate Isomerase of Entamoeba histolytica in the
Formation of Cyst-like Structures. H. AGUILAR-DIAZ*, J.P. LACLETTE and J.C. CARRERO-SÁNCHEZ,
Department of Immunology, Institute of Biomedical Research, UNAM.
The cyst, the infective form of the Entamoeba histolytica, is a structure surrounded by a chitin wall highly
resistant to adverse environment conditions. The encystment process represents a target to inhibit the
amoeba life cycle and impede its spreading. Unfortunately, E. histolytica has not been encysted in vitro.
Giardia intestinalis cyst wall consist of a N-acetylgalactosamine polymer, which is synthesized by a
biosynthetic pathway where the rate limiting enzyme is the Glucosamine-6-phosphate isomerase
(GlcN6pI). For that reason, it could be possible that E. histolytica encystment depends on the controlled
expression of this enzyme. In order to induce the formation of cyst-like structures, 100 mM of H2O2 in
combination with chitin synthasa cofactors were added to trophozoites in TYI-S33 medium. The
rounded structures obtained were stained with white calcofluor to evaluate the chitin presence. Nacetylglucosamine polymers were determined in a quantitative way by as ELISA test using wheat germ
agglutinin. The expression of the E. histolytica GlcN6PI was evaluated by RT-PCR in treated trophozoites. Three fragments of the promotor (-1 to –280; -470; –680) were cloned into pBSCAT vector in
order to carry out CAT assay studies. The results revealed positive fluorescence of the cyst-like structures
stained with white calcofluor, suggesting the presence of chitin, which also was detected with the ELISA
test. The treated trophozoites display enzyme mRNA over-expression with respect to the untreated ones,
which diminished about a half in mature cysts. CAT activity was observed with fragments –680 and –
470bp, but it was loosed with the fragment –280bp, suggesting that the elements needed for the transcription of this gene are present within the –470bp upstream. The obtaining of E. histolytica cyst-like
structures in vitro and the understanding at molecular level of the encystment process will help to identify
possible cyst targets that could be the base for the development of new anti-amoebic drugs and the
eradication of this parasite.
64
Tamoxifen Treatment Induces Protection in Murine Cysticercosis. J.A. VARGAS-VILLAVICENCIO*, C.
LARRALDE, M.A. DE LEÓN-NAVA, G. ESCOBEDO and J. MORALES-MONTOR, Departamento de
Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
Administration of Tamoxifen (an anti-estrogen) produced an 80% parasite-load reduction in female
mice, and a weaker effect of 50% in male mice. This protective effect was associated in both sexes with
an increase in the mRNA levels of IL-2 (a cytokine associated in protection against cysticerci) and IL-4
(innocuos against infection). Tamoxifen treatment modified 17-β estradiol production in females, while
serum testosterone was not affected. However, the expression of the two types of estrogen receptor, ERα and ER-β, in the spleen of infected mice of both sexes, was decreased by Tamoxifen treatment. In vitro
treatment of T. crassiceps with Tamoxifen reduced reproduction and loss of motility. These results indicate
that Tamoxifen treatment is a new therapeutic possibility to treat cysticercosis, since it can act at both
ends of the host–parasite relationship: increasing the cellular immune response protective against the
parasite and affecting directly the parasite´s reproduction and survival.
65
Follow-up of Physical Discomfort and Health Status of Golden Hamsters Used as Experimental Definitive Hosts of Taenia solium, Employing Two Non-steroid Drugs for Immunosuppression. D.E. JIMÉNEZGONZÁLEZ*, R. GARCIA-CORTES, Departamento de Ecologia de Agentes Patogenos, Hospital
General “Dr. Manuel Gea González,” SSA, México DF, G. AVILA-RAMIREZ, A. FLISSER, Departamento
82
ABSTRACTS
de Microbiologia y Parasitologia, Facultad de Medicina, UNAM, México DF, and P.J. MARAVILLACAMPILLO, Departamento de Ecologia de Agentes Patogenos, Hospital General “Dr. Manuel Gea
González,” SSA, México DF, México.
The golden hamster as an experimental model of human taeniosis has been shown to be a good alternative for studying Taenia solium. However, elevated physical discomfort, wasting syndrome and infections
are frequent in immunosuppressed rodents. The objective of this work was to evaluate the effect of
methotrexate (MTX) and mycophenolate mophetyl (MPM) as immunosuppressive non-steroid drugs as
compared to the drug usually used, methyl-prednisolone acetate (MPA), in the health of golden hamsters
infected with T. solium; the effect of these drugs also was evaluated during evagination of cysticerci. After
infection and immunosuppression, weekly physical examinations included behavioral and physical
parameters. Each parameter was scored between 0 and 3, depending on the degree of discomfort.
Animals were euthanized humanely when the addition of all parameters exceeded 12 points, which
represented a critical condition in the state of the host. At necropsy, tapeworms were searched and
recovered from the small intestine. Behavioral and physical parameters showed that MTX and MPM
generated a low physical discomfort on rodents, the highest average score was 7.5 for MTX and 6 for
MPM at six weeks post-infection (WPI), but at necropsy, no tapeworms were found. AMP immunosuppressed hamsters had an average score of 10 at six WPI, and at necropsy 100% of the hamsters in this
group were infected, with eight tapeworms measuring between 28 and 39 cm obtained. All cysticerci
cultured in 25% bile evaginated, while adding MTX or MPM, evagination was reduced in 50 and 60%,
respectively. Our data suggest that other non-steroid drugs should be assessed in order to reduce the
effects on the general state of health and to avoid unnecessary suffering of the experimental animals, but
assuring that tapeworms will develop.
66
Prochristianella Sp. Parasiting the Octopus, Octopus maya in Dzilam de Bravo, Yucatán, Northern
Yucatán Peninsula. A. LÓPEZ-STRUCK* and S. GUILLÉN-HERNÁNDEZ, Campus de Ciencias Biológicas y Agropecuarias, Departamento de Biología Marina, Universidad Autónoma de Yucatán,
Mérida, Yucatán, México.
The octopus (O. maya) is one of the most important resources of the Yucatán Peninsula due to its great
commercial value. Despite its great importance, however, there is a lack of studies on parasite ecology, a
very important aspect for the development of the potential mariculture of this species. In this preliminary
study, a cestode larvae (Prochristianella sp.) was found showing the highest value of prevalence, mean
intensity and mean abundance in O. maya. Therefore, for the first time we describe a host–parasite
relationship between O. maya and the larvae of Prochristianella sp. during a four-month period of sampling. From August to November 2006, a total of 43 individuals (O. Maya) taken from the commercial
catch at Dzilam de Bravo, Yucatán were examined. Thirty-three individuals were infected by the cestode
larvae (Prochristianella sp.), showing a prevalence of 76.74%, a mean intensity of 11.33 and a mean
abundance of 16.28. Ninety-nine percent of the collected parasites were found in the buccal cavity.
67
Miracidia of F. hepatica Lyses Proteins and Nucleic Acids During Invasion of the Intermediate Hosts.
L.B. ORTÍZ-ALEGRÍA*, Instituto Nacional de Pediatría, SSA, Torre Investigación, México DF, C.P. RICOTORRES, Instituto Nacional de Pediatría, SSA, Torre Investigación, México DF, I. CRUZ-MENDOZA, H.
QUIROZ-ROMERO, FMVZ, UNAM, and D. CORREA, Instituto Nacional de Pediatría, SSA, Torre
Investigación, México DF, México.
Fasciolosis is a prevalent and economically important disease of livestock having a significant impact on
growth, development and productivity in ruminants. Newly excysted juvenile forms and adult proteinases
hydrolyze a variety of proteins and are involved in invasion. Infection of the intermediate hosts (Lymnaeid snails) by the miracidia of the trematode follows penetration of epithelial barriers. The miracidium
of F. hepatica presents vesicles in the apical gland, which are emptied at the host–parasite interface during
invasion. These vesicles could contain proteolytic enzymes. In fact, this aspect has been studied more
extensively in the Schistosoma mansoni miracidia, which shows proteolytic activity (mainly by thiolproteases) in lateral glands, total extracts and excretory–secretory products. In this project, the role of
proteinases in invasion is under study. For this purpose, the first gross experiment in order to determine
83
ABSTRACTS
if there is partial degradation of the mollusk proteins, Lymnaea humilis snails are infected by incubation
with one to twenty freshly hatched miracidia, and directly analyzed by SDS-PAGE under reducing
conditions; in a first experiment, no degradation was observed, although it was only possible to use one
miracidium per host. Nucleic acids were purified from these snails as well, and, unexpectedly, we found
degradation, even with these low parasite burdens. Apparently, the DNA was preserved, and the bands
for the ribosomal RNA were seen partially degraded. This degradation inhibited the PCR technique for
rRNA and cytochrome oxidase c subunit 1. The addition of RNAse completed the RNA degradation
and the PCR performance was restored. The role of these processes in snail invasion deserves further
investigation.
68
Evaluation of Taenia solium Calreticulin as an Oral Vaccine in Experimental Tapeworm Infection. S.
LEÓN-CABRERA*, M. CRUZ-RIVERA, G. AVILA-RAMIREZ, F. MENDLOVIC and A. FLISSER, Departamento de Microbiología y Parasitología, Facultad de Medicina, UNAM.
Human neurocysticercosis is caused by the larval stage of the cestode Taenia solium. It is a public health
problem in many developing countries and an emerging disease in some developed ones. Many epidemiological studies have demonstrated that a human carrier of the intestinal T. solium is the main risk
factor in the transmission of neurocysticercosis. There are few studies on taeniosis because humans are
the only natural definitive hosts, and no effective vaccines have been produced. Recombinant T. solium
calreticulin (rTsCRT) has been identified and characterized. It is a functional protein found in subtegumentary and muscle cells of cysticerci and tapeworms and it is expressed during embryogenesis. Therefore, we used rTsCRT to evaluate if it induces protection against experimental T. solium tapeworm
infections in hamsters. Three oral immunizations with 100 µg of rTsCRT alone or with cholera toxin
(CT) or crude extract of Macracanthorhynchus hirudinaceus (CE) as adjuvant were given to hamsters.
Control groups were immunized with CT, CE or PBS. Three weeks after the last immunization, hamsters
were challenged with four cysticerci that had 95% evagination, obtained from a naturally infected pig. In
the necropsy, the groups of animals immunized with rTsCRT and TC or without TC did not develop
tapeworms 21 days after challenge. Control groups immunized with CT, CE or PBS developed tapeworms measuring up to 6.5 cm. Our preliminary results suggest that the immune response induced by
rTsCRT prevents the establishment of the tapeworm; therefore, it can be a good candidate for the
development of a vaccine against human taeniosis, which would interrupt the life cycle of T. solium.
69
Characterization of the Endocytic Pathway and Use as an Iron Source of Ferritin by Entamoeba histolytica. F. LÓPEZ-SOTO*, M. REYES-LÓPEZ, Depto. de Biologia Celular, CINVESTAV-IPN, México DF, N.
LEÓN-SICAIROS, Depto. de Investigacion del Hospital Pediatrico de Sinaloa, Culiacan, Sinaloa, A.
GONZÁLEZ-ROBLES, Depto. de Patologia Experimental, CINVESTAV-IPN, México DF, and M. DE LA
GARZA, Depto. de Biologia Celular, CINVESTAV-IPN, México DF, México.
Iron is an essential element for growth of nearly all organisms; it is not free in the cell due to its toxicity.
Ferritin is an iron-storage protein containing up to 4,500 atoms of Fe (III) that is found throughout
evolution from bacteria to humans with small differences in structure. It is mainly found in the liver,
spleen and brain of mammals. In infectious processes, ferritin synthesis increases in order to sequester
iron, avoiding its availability to invaders. Reports of pathogens using host ferritin as a source of iron are
few. Fewer studies have been done regarding ferritin endocytosis; in oligodendrocytes, ferritin is internalized via clathrin-coated vesicles. Previous work by our group has shown that Entamoeba histolytica, the
parasite causing amoebiasis, utilizes human hemoglobin, transferrin and lactoferrin as sources of iron for
growth. In the liver, an amoeba could interact with ferritin, which probably provides enough iron for the
parasite’s survival. We researched whether E. histolytica uses ferritin as an iron source for growth in axenic
cultures; we also characterized the endocytic pathway by confocal and electronic microscopy, flow
cytometry, and substrate gel electrophoresis. Trophozoites maintained their viability (80%) in 50 µg/ml
ferritin (100 µM iron). Cysteine proteases from culture supernatants and crude extracts cleaved ferritin,
producing mainly three fragments of 180, 120 and 23 kDa. Amoebas endocytosed FITC-ferritin and
cationized-ferritin, a process initiated at 1–2 min of incubation; after this time, ferritin was located in
cytosol vesicles. Ferritin endocytosis was through clathrin vesicles, since it was inhibited with chloro84
ABSTRACTS
quine and other classical clathrin inhibitors. Also, it was dependent on a ferritin binding-protein, because
this process was inhibited by trypsin treatment. Ferritin endocytosis behaved as a regulated process,
leading to the saturation of the ferritin binding-protein. The capacity of amoebas to use ferritin for
survival could help explain the parasite’s virulence in the liver and the cause of hepatic abscesses.
70
Leishmania mexicana Inhibits the Apoptosis in Monocyte-derived Dendritic Cells. L. VALDES-REYES*,
M. BERZUNZA-CRUZ, N.L. SALAIZA-SUAZO, M.M. AGUIRRE-GARCÍA, I.D. BECKER, Departamento
de Medicina Experimental, Facultad de Medicina, UNAM, J. MORAN, Departamento de Neurociencias, Instituto de Fisiología Celular, UNAM, and L. GUTIÉRREZ-KOBEH, Departamento de Medicina Experimental, Facultad de Medicina, UNAM.
Leishmania mexicana is a protozoan parasite that infects macrophages and dendritic cells (DC) and causes
diverse clinical forms of leishmaniasis. The mechanism of apoptosis has been recognized as an important
way of defense during the innate and adaptive immunity for its role in the elimination of infected cells
and maintenance of homeostasis in the immune system. In this work, we analyzed the effect of Leishmania in the apoptosis of DC and showed that the parasite inhibited the translocation of phosphatidylserine
and activation of caspase-3 in DC. Mononuclear cells were obtained from human peripheral blood using
Histopaque. Monocytes were isolated with α-CD14 magnetic beads and differentiated to moDC with
GM-CSF and IL-4 for seven days. One x 106 moDC were incubated with a different number of promastigotes of Leishmania mexicana for 12 hours, dyed with Annexin V-FITC and analyzed by flow cytometry. The effect on the activity of caspase-3 was determined by fluorometry using a fluorogenic peptide
substrate. moDC had a basal apoptosis of 1%, which increased to 46% when treated with the inducer
camptothecin. The incubation of moDC with the parasites caused an inhibition of the induced apoptosis
in 98% in a dose-dependent manner. Also, Leishmania mexicana exerted a reduction in the activity of
caspase-3 in moDC and inhibited the camptothecin-induced DNA fragmentation, as analyzed by gel
electrophoresis. The inhibition of the apoptosis of moDC by Leishmania mexicana could provide a safe
niche for the parasites to survive and can have significant consequences for disease development. (Supported by grants 34828-M from CONACyT, México and IN-220207 from DGAPA, UNAM.)
71
Participation of a Protein Tyrosine Phosphatase from Leishmania mexicana in the Infection of Macrophages. J. GÓMEZ-SANDOVAL, A. ESCALONA-MONTAÑO, D. PARDAVÉ-ALEJANDRE, R. CERVANTES
and L. GUTIÉRREZ-KOBEH, Departamento de Medicina Experimental, Facultad de Medicina, UNAM,
México DF, M. GUTIÉRREZ-QUIRÓZ, Departamento de Microbiology, Facultad de Medicina, UNAM,
México DF, and I.D. BECKER and M.M. AGUIRRE-GARCÍA*, Departamento de Medicina Experimental, Facultad de Medicina, UNAM, México DF, México.
Leishmania mexicana is an intracellular protozoan parasite that causes chronic cutaneous disease. Although many enzymatic activities have been reported in this parasite, the presence of kinase and phosphatases has been poorly studied. The protein tyrosine kinase (PTK) phosphorylate tyrosine residues and
protein tyrosine phosphatases (PTPases) dephosphorylate tyrosine residues. PTPase activities have been
reported as pathogenic factors in various infectious microorganisms such as viruses, bacteria, and parasites. Also, it has been shown that the induction of one or more PTPase activites represents an important
factor in the pathogenicity of Leishmania. Recently, we reported membrane-bound PTPase activity in
promastigotes of Leishmania major. In the present work, we give evidence that promastigotes of Leishmania mexicana are able to secrete a PTPase in culture medium. The pattern of sensitivity and resistance to
specific phosphatase inhibitors allows us to characterize it as a protein tyrosine phosphatase. The mAb
anti-PTPase1B from human placenta recognized a molecule of 50-55 kDa in supernatant of cultured
promastigotes. The incubation of promastigotes with 20 µM sodium vanadate and Peroxovanadium
(PTPase inhibitors) inhibited the PTPase activity 50% and 75%, respectively. Also, the infection of
murine macrophages with Leishmania promastigotes, treated with Peroxovanadium, showed a rate of
infection of 80% as compared to untreated parasites. However, when both PTPase of the Leishmania and
macrophages were treated with peroxovanadium, the percentage of the infection decreased to 60%.
These results suggest the importance of PTPases in the infection by Leishmania promastigotes. (This
work was supported by grants IN221606 from DGAPA and 45052-M from CONACyT México.)
85
ABSTRACTS
72
Leishmania mexicana Lipophosphoglycan (LPG) Stimulates the Expression and Function of Nitric Oxide
Synthase in Murine Dendritic Cells. A. WILKINS-RODRÍGUEZ*, I.D. BECKER and L. GUTIÉRREZKOBEH, Laboratorio de Inmunoparasitología, Departamento de Medicina Experimental, Facultad de
Medicina, UNAM.
Leishmania are dimorphic protozoan parasites, which are transmitted by the phlebotomine sandfly to
mammalian hosts. Leishmania species cause a wide range of pathologies in humans and may be fatal if
left untreated. In cutaneous leishmaniasis, skin macrophages (Mφ) and dendritic cells (DC) are sequentially parasitized, and DC, rather than Mφ, are responsible for Th priming and the initiation of Th
education in this disease. Professional phagocytic cells express a number of antimicrobial compounds,
aiding the control of microbial intracellular proliferation. Among these, nitric oxide (NO) has been
described as a potent agent capable of limiting the growth of several intracellular parasites. NO appears
to be the primary molecule associated with the killing of leishmanial amastigotes. Since DC internalizes
amastigotes and somehow destroys them to prime T cells, we investigated if LPG from L. mexicana was
able to induce the expression and function of iNOS. Bone marrow-derived dendritic cells were stimulated with LPG from L. mexicana. In some cases, cells were primed with IFN-γ. LPG and IFN-γ/LPG
upregulated the expression of mRNA for iNOS, as determined by densitometric analysis of the PCR
products resolved in 2% agarose gels. Also, the activity of the enzyme was upregulated, as shown by NO
production, quantitated as nitrites by Griess reagent. DC in medium alone produced less than 2 µM
NaNO2, the stimulation with LPG and IFN-γ/LPG increased the NaNO2 production to 7 and 28 µM,
respectively. Our findings show that LPG is able to activate the NO machinery, which suggests that
besides Mφ, DC could function in the innate response against Leishmania. (Work supported by grants
IN220207 from DGAPA, UNAM and 34828-M from CONACyT, México.)
73
Effect of Sexual and Adrenal Hormones on the Proliferation of Entamoeba histolytica. C. CERVANTESREBOLLEDO*, Department of Immunology, Instituto de Investigaciones Biomédicas, UNAM, México
DF, J. MORALES-MONTOR, Department of Immunology, Instituto de Investigaciones Biomédicas,
UNAM, México DF, N. MORENO, Department of Cell Biology and Physiology, Instituto de Investigaciones Biomédicas, UNAM, México DF, M. NEQUIZ, Department of Experimental Medicine, Facultad
de Medicina, UNAM, Mèxico DF, J.P. LACLETTE, Department of Immunology, Instituto de Investigaciones Biomédicas, UNAM, México DF, and J.C. CARRERO-SÁNCHEZ, Department of Immunology,
Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
Recently, interactions between the nervous, endocrine and immune systems have acquired importance as
a determinant in the control of parasitic infections. The Hypothalamic-Pituitary-Adrenocortical (HPA)
and Hypothalamic-Pituitary-Gonadal (HPG) axes are involved in those regulations due to the direct
influence of hormones on parasites growth and an indirect effect on the host immune response. Since the
sex is a determinant factor in the outcome of many infections, and there are few related reports in the
Entamoeba histolytica infection, in the present work we evaluated the direct in vitro influence of several
hormones on the proliferation of E. histolytica trophozoites. The results showed that the treatment of
cultures with variable concentrations of the HPA hormones, dehydroepiandrosterone (DHEA) and
cortisol, affected the trophozoite growth in a dose-dependent manner: DHEA inhibiting it from very
low concentrations (0.1 g/ml) and cortisol stimulating it. On the other hand, sexual hormones such as
progesterone, estradiol and testosterone did not affect the parasite proliferation. The inhibitory effect of
HPA hormones on ameba proliferation was confirmed by evaluating the level of DNA replication in
tritiated-thymidine incorporation assays. In order to determine the mechanism by which DHEA killed
the trophozoites, apoptosis and necrosis assays by TUNEL and propidium iodide staining were carried
out, suggesting that trophozoites were dead by a necrotic process. In contrast to the in vitro anti-proliferative property of DHEA, the intraperitoneal treatment of hamsters with different doses of this hormone increased the size and lesions of amebic liver abscesses with respect to non-treated, but infected
animals. This in vivo result suggests that DHEA or its metabolites interact with host factors that favor
the development of the amebic liver abscess. A possibility is that DHEA upregulates the host´s cellular
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ABSTRACTS
immune system, which, in turn, contributes to the tissue damage during the liver infection by E. histolytica, as has been suggested elsewhere.
74
Induction of High Levels of Tumor Necrosis Factor α and Nitric Oxide by Virulent Mexican Strain of
Trypanosoma cruzi. A. JIMÉNEZ-MARIN* and B. ESPINOZA, Departamento de Inmunologia, Instituto
de Investigaciones Biomedicas, UNAM, Cuidad Universitaria, México DF, México.
Trypanosoma cruzi is an obligate intracellular protozoan parasite of mammals and the etiologic agent of
Chagas disease. This parasite infects a variety of host cell types, including macrophages, which is the first
cell that interacts with the parasite immediately after crossing the cutaneous barrier. In T. cruzi infections,
gamma interferon (IFN-γ) produced by NK cells and T cells, activates macrophages to release nitric
oxide (NO) and kill the obligate intracellular amastigote forms of the parasite. Tumor necrosis factor
alpha (TNF-α), another cytokine associated with macrophage activation, provides a second signal to
induce microbicidal activity in IFN-γ-activated macrophages by stimulating NO production. The aim of
this work was to analyze the response of IFN-γ-activated J774 macrophages to the infection of two T.
cruzi Mexican strains that display different degrees of virulence and pathogenicity in the murine model.
The results revealed differences in the capacity of invasion of both strains, being the infection of the
virulent strain two-fold higher than the non-virulent strain. With respect to the trypanocidal response of
the macrophages, when NO production was evaluated by the Griess method, the results showed that the
non-virulent strain induced NO 15 times more than the virulent strain. There were no differences in the
production of cytokines IL-12, IL-10 in the expression of chemokines RANTES and MCP-1. TNF-α
production, however, was higher in cells infected with the virulent strain, both with or without IFN-γ
incubation. These results suggest that the analyzed strains of T. cruzi may establish different interactions
with the surface of macrophages or inducing different signal pathways during the first stages of the
infection.
75
Macrophage Migration Inhibitory Factor Plays a Role in Leishmania mexicana Infection. M. ROMEROGRIJALVA*, I. RIVERA-MONTOYA, L.I. TERRAZAS-VALDÉS and M. RODRÍGUEZ-SOSA, Laboratorio
de Inmunoparasitología, UBIMED, FES, Iztacala, UNAM, México.
MIF is a 12 KDa highly conserved trimeric protein that acts as an enzyme hormone and cytokine. MIF
has been associated with the delayed type hypersensitivity response, regulation of innate immunity and
promotion of protective immunity or as a factor involved in the development of adverse pathology.
These roles of MIF in immunity have prompted investigators to study its role in parasitic infection.
Using MIF+/+ and MIF-/- males and females BALB/c mice, we analyzed the role of endogenous MIF
in regulating the innate and adaptive immune response after intra-dermal Leishmania mexicana infection.
No differences in the lesion size were observed between the groups MIF+/+ vs MIF-/-, but, interestingly, MIF-/- mice displayed greater parasitic load than MIF+/+ mice at three, five and eight weeks
post-infection. Moreover, MIF-/- females displayed greater parasitic loads at 3 and 5 weeks post-infection
compared with MIF-/- males. After eight weeks post-infection, the differences in parasite load between
the genders were lost, but not the differences between groups MIF+/+ vs MIF-/-. In the adaptive
immunity, it was observed that MIF-/- mice males and females at 2, 4 and 6 weeks post-infection displayed low levels of IL-4, TNF-alfa compared with MIF+/+. Interestingly, MIF-/- mice expressed higher
levels of IFN-gama than MIF+/+ mice. In the innate immunity, TNF-alfa, Arginase-1 and iNOS
expression were downregulated in the MIF-/- mice. The expression of IL-12p35 was greater in MIF+/+
mice than mice MIF-/-; in contrast, IL-12 p40 was smaller in the MIF+/+ females than the MIF-/females. Together these data indicate that MIF contributes in the protective immune response to Leishmania mexicana, modulating the expression of some cytokines from the innate immune response such as
TNF-alfa, IFN-gama and the enzyme iNOS, all of them necessary to control the early replication of the
parasite.
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76
Increased Susceptibility to Toxoplasma gondii Infection in AhR-null Mice. M. RODRÍGUEZ-SOSA*, L.I.
TERRAZAS-VALDÉS, I. RIVERA-MONTOYA, Unidad de Biomedicina, FES, Iztacala, UNAM, México, G.
ELIZONDO and L. VEGA, Toxicología, CINVESTAV-IPN, México.
Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor for CYP1A1. Recently, it has
been suggested that AhR plays a role in the immune system by down-regulating Th1-type responses.
Here, we used AhR-/- (AhR-null) and AhR+/+ (WT) C57BL6 mice to determine the role of AhR in
the regulation of host immune response against Toxoplasma gondii infection. Following i.p. infection with
40 cysts of ME49 strain, AhR-null mice developed severe clinical signs of sickness, a higher reduction in
body weight and succumbed to T. gondii infection faster than WT mice. Enhanced susceptibility of AhRnull mice was associated with higher levels of TNF-α in their sera. AhR-null and WT mice produced
comparable levels of IFN-gamma, IL-10 and IL-4 along the infection. AhR-null mice showed significantly fewer eosinophils than WT mice. Brains from T. gondii-infected AhR-null mice accumulated less
parasite cysts when compared to WT infected mice. These data show that AhR-null mice display increased susceptibility to T. gondii infection likely associated with a high pro-inflammatory response that
may control parasite replication but causing damage to the host during the infection. (Work supported
by grants 36272 CONACyT and IN208606 PAPIIT-UNAM.)
77
Taenia crassiceps: Relevance of Parasite Genetic Changes on the Host Susceptibility and Immunity. G.
MENESES, R.J. BOBES, E.L. SCIUTTO* and G. FRAGOSO, Instituto de Investigaciones Biomedicas,
UNAM, Ciudad Universitaria, México DF, México.
Taenia crassiceps cysticerci develop in the peritoneal cavity of BALB/cAnN mice (susceptible) and, to a
lesser extent, in BALB/cJ (resistant) mice. Susceptibility differences are shown during the first days after
infection, pointing to the relevance of differences in the early immunity between these strains. Studies of
the peritoneal cell population and proinflammatory cytokines levels by flow conducted from 2001 to
2004 revealed that resistant BALB/cJ mice exhibited a significant increase in macrophages, NK cells and
IFN-γ; in respect to those susceptible mice. In additional studies performed after 2004, differences in the
susceptibility were modified, with BALB/cAnN being more resistant than BALB/J. BALB/cAnN also
exhibited an increase in macrophages, NKcells and IFN-γ, all features related to resistance. Differences
between parasites from 2001 and 2004 were determined by RAPIDs, which could account for these host
differences in the susceptibility. Nevertheless, results shown herein point to the relevance of the innate
immunity in the early control of Taenia crassiceps cysticercosis.
78
Localization of TSOL18 and TSOL45 in Different Stages of Taenia solium. J. MARTÍNEZ-OCANA*,
Hospital General “Dr. Manuel Gea González,” México DF, M. GARCIA-DE-LEÓN, Departamento de
Medicina Experimental, Facultad de Medicina, UNAM y Hospital General de México, México DF, C.
GAUCI, M. LIGHTOWLERS, The University of Melbourne, Veterinary Clinical Centre, Victoria, Australia, and A. FLISSER, Departamento de Microbiología y Parasitología, Facultad de Medicina, UNAM,
Mèxico DF, México.
Tenia solium causes cysticercosis in swine and humans. An alternative measure to control this disease is by
vaccination. In experimental trials with swine, vaccines prepared as the recombinant antigens TSOL18
and TSOL45 prepared from Tenia solium oncosphere mRNA showed 99.5% protection against cysticercosis. The distribution and localization of these antigens in Tenia solium is unknown. The objective of the
present study was to identify the expression of TSOL18 and TSOL45 antigens in the parasite. Immunoperoxidase labeling was carried out using pig hyperimmune serum collected during the vaccine trial.
Cysticerci and adult tapeworms (scolex, immature, mature and gravid proglottids) were fixed in formalin, embedded in paraffin blocks, and continuous 4 um sections were prepared. All tissues were deparaffinized and hydrated using graded alcohols and incubated in hydrogen peroxide in PBS to quench
endogenous peroxidase activity. As the negative control, the pre-immune pig serum was used. After
incubation with specific or control sera, the tissues were submitted to biotin anti-pig IgG antibody,
avidin biotin reagent and diaminobenzidine, in sequential incubations; finally, they were counterstained
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in hematoxylin. The results showed that TSOL45 antigen was distributed mainly in the numerous testes
and the ovaries of gravid proglottids. Nevertheless, TSOL18 and TSOL45 antigens did not react with
oncopheres, probably because these antigens have an up-regulated expression when oncospheres are
activated, and this is lacking in oncospheres located within proglottids.
79
Protein Tyrosine Phosphatase from Entamoeba histolytica Modulate the Activation of Phagocytic Cells.
J. ESPEJEL-ZARAGOZA, A. RUIZ-REMIGIO, M. NEQUIZ, A. ESCALONA-MONTAÑO, Departamento
de Medicina Experimental, Facultad de Medicina, UNAM, México DF, P. TALAMÁS-ROHANA, Departamento de Patología Experimental, CINVESTAV-IPN, and M.M. AGUIRRE-GARCÍA*, Departamento de
Medicina Experimental, Facultad de Medicina, UNAM, México DF, México.
Entamoeba histolytica is an invasive organism capable of lysing a variety of host cells, including hepatocytes, intestinal cell lines, neutrophils, lymphocytes, and macrophages. Although many enzymatic
activities have been reported in E. histolytica, the presence of phosphatases has been poorly studied.
Protein tyrosine phosphatases (PTPases) dephosphorylate tyrosine residues. PTPase activities have been
reported as pathogenic factors in various infectious microorganisms, such as the PTPase of Yersinia that
inhibits phagocytosis and the oxidative burst in macrophages. Our group has reported the existence of a
membrane-bound protein tyrosine phosphatase (mPTPase), as well as one secreted to the extracellular
medium (sPTPase). The mPTPase has been purified and characterized. The interaction of this mPTPase
with HeLa cells altered the cell actin cytoskeleton by disruption of the actin stress fibers. In the present
study, we analyzed the effect of this mPTPase on the oxidative burst of neutrophils activated with fMLP
and PMA and cytokines production by macrophages incubated with LPS. Results show that mPTPase
inhibits the oxidative burst in neutrophils activated with fMLP in a dose-dependent manner. When
neutrophils were activated with PMA, however, the effect of the amoebic enzyme on the oxidative burst
was not observed. Pre-incubation of the cells with amoebic mPTPase increased the levels of TNFα, IL-10
and decreased the level of IL-12. Our results suggest that the mPTPase of E. histolytica may modulate the
activation of phagocytic cells by inhibiting the production of oxygen radicals and, at the same time,
through pro-inflammatory mechanisms that favour trophozoites dissemination and migration into the
liver, contributing to the amoebic abscess formation. (Work supported by grants IN221606 from
DGAPA and 45052-M from CONACyT México.)
80
Chloroquine Has an Immunomodulatory Role in BALB/c Mice Infected with Plasmodium yoelii 17xl. A.
RAMOS-AVILA*, FES Zaragoza, Posgrado en Ciencias Biológicas, UNAM, México DF, J.L. VENTURAGALLEGOS, Instituto de Investigaciones Biomédicas, UNAM, México DF, and M. LEGORRETAHERRERA, FES Zaragoza, UNAM, Posgrado en Ciencias Biológicas, México DF, México.
Treatment with the antimalarial drug chloroquine (CLQ) has been used successfully in autoimmune
diseases as systemic lupus erythematosus and rheumatoid arthritis, even when the mechanism of action is
not well understood. The improvement in patient’s clinical condition has been attributed to the induction of apoptosis in lymphocytes. Since these cells are central to control the malaria infection in this work
we study how the treatment with chloroquine modifies the apoptosis of spleen cells in mice infected with
Plasmodium yoelii 17XL (Py 17XL). Furthermore, we evaluated the mRNA expression level of IL-10, an
anti-inflammatory cytokine and TNF-a a proinfammatory cytokine. Groups of BALB/c mice were
infected with Py 17XL. On day 7 post-infection, the mice were treated with a therapeutic dose of
chloroquine; 24 hrs later, the mice were sacrificed, and the spleen cells were used to evaluate apoptosis
and the expression level of cytokines IL-10 and TNF-a by a semi quantitative RT-PCR. The results
indicate that chloroquine treatment increases apoptosis of spleen cells in Py 17XL infected mice, decreases the level of IL-10 expression, and increases the level of TNF-a. These results suggest that chloroquine not only eliminates the parasite, but also induces apoptosis of spleen cells and modulates the
expression of pro-inflammatory and anti-inflammatory cytokines during a malaria infection. (This work
was supported by PAPIIT IN214007 and 5782-Q CONACyT Grants.)
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81
Analysis of TLR1, TLR2and TLR6 In NK Cells of Patients with Cutaneous Leishmaniasis. I.C. CAÑEDAGUZMÁN*, Departamento de Medicina Experimental, Facultad de Medicina, UNAM, G. CARRADAFIGUEROA, Universidad Autónoma de Tabasco, N.L. SALAIZA-SUAZO and I.D. BECKER, Departamento de Medicina Experimental, Facultad de Medicina, UNAM.
The family of Toll-like receptors (TLRs) recognize conserved patterns present in microorganisms and
participate in the activation of innate immune cells. Each TLR recognizes distinct classes of molecules
present in pathogens. TLR2 recognizes a variety of molecules present in pathogens due to its association
with TLR1 or TLR6. LPG (lipophosphoglycan) from Leishmania major is a glycoconjugate abundantly
expressed on the surface of different Leishmania species. Previously, we have shown that TLR2 recognizes
LPG, leading to NK cell activation and cytokine production. Yet it has not been established whether
TLR2 forms heterodimers with TLR1 or TLR6 and if this association correlates with the disease
outcome in leishmaniasis. In the present study, we analyzed the expression of TLR2, TLR1 and TLR6
by flow cytometry and the IFN-gamma and TNF-alpha production by ELISA in NK cells of three
healthy controls and five patients with localized cutaneous leishmaniasis (LCL). The cells were stimulated with 10 ug/ml LPG during 18 hrs. Results: Our results show that when NK cells are stimulated
with LPG, they upregulate their TLR1, TLR2 and TLR6 expression in healthy controls as well as
patients with LCL, yet the NK cells of LCL patients secrete twice as much TNF-alpha and four times as
much IFN-gamma as healthy controls. Apparently, there is no clear association between the TLR expression and the cytokine production in NK cells. We conclude that the upregulation of both TLR1 and
TLR6 in association with TLR2 possibly indicates that the recognition of LPG requires the participation
of heterodimes formed by TLR1 and TLR2 or of TLR6 and TLR2. It remains to be established if this
combination of TLR1, TLR2 and TLR6 also occurs in patients with diffuse cutaneous leishmaniasis.
(Grants: DGAPA 221806-3 and CONACyT 47256-M.)
82
Toward Taenia solium Control: Field Trial Evaluation of the S3Pvac Anti-cysticercosis Vaccine Expressed
in Filamentous Phages. J. MORALES*, J.J. MARTÍNEZ, Facultad de Medicina Veterinaria y Zootecnia,
UNAM, Ciudad Universitaria, México DF, M. HERNÁNDEZ, Departamento de Inmunologìa, Instituto
de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México DF, K. MANOUTCHARIAN,
Departamento de Biotecnologìa, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México DF, G. GEVORKIAN, G. ACERO, Departamento de Inmunologìa, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México DF, A. BLANCAS, Instituto de Investigaciones Biomedicas, UNAM, Planta Piloto, Ciudad Universitaria, México DF, A. TOLEDO,
Departamento de Inmunologìa, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria,
México DF, V.M. MAZA, Secretaria de Desarrollo Agropecuario, Programa de Salud Animal, Cuernavaca, Mor. México, A. ALUJA, Facultad de Medicina Veterinaria y Zootecnia, UNAM, Ciudad Universitaria, México DF, A. FLEURY, Instituto Nacional de Neurologia y Neurocirugia Manuel Velasco Suarez,
Tlalpan, México DF, G. FRAGOSO, C. LARRALDE and E.L. SCIUTTO, Departamento de Inmunologìa,
Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México DF, México.
Taenia solium is a major parasitic disease that seriously and frequently affects human health and economy
in developing countries. Since pigs are an indispensable intermediate host, transmission could be reduced
by reducing pig cysticercosis through vaccination. The S3Pvac synthetic vaccine has proved to induce
high level of protection against pig cysticercosis in the field and reduce the viability of those established.
S3Pvac is composed by peptides of 8 (KETc12), 12 (KETc1) and 18 (GK1) amino acid peptides derived
from the KETc7 protective peptide. To improve the developed vaccine reducing its cost and increasing its
immunogenecity, the vaccine peptides were recombinantly expressed in M13 filamentous phage. This
multiepitope recombinant bacteriophage anti-cysticercosis vaccine inactivated induces high levels of
protection against pig cysticercosis under experimental conditions. Herein, the efficacy of this new
vaccine against pig cysticercosis in 16 rural communities of “Sierra de Huautla” in the State of Morelos,
México was determined. Before the vaccination program began, a prevalence of 14 % of pig cysticercosis
was found by tongue inspection in a total of 632 of the 1,461 pigs estimated in these communities. A
total of 1,047 pigs of three to four months of age were included in the vaccination schedule (626
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vaccinated + 421 controls). Six to seven months later, the effect of vaccination was determined by
tongue inspection in 532 of the 1,047 pigs. Vaccination significantly reduced pig cysticercosis from
12.9% (29/225) to 3.9% (12/307). The effect of the vaccine also was determined in 331 pigs (197
vaccinated + 134 controls) sacrificed by their owners for their consumption. The masseters, tongue,
diaphragm and heart of each one were inspected and the number of cysticerci determined. Vaccination
reduced in 54.2% the number of infected pigs and in 81.2% the number of parasites established with
some differences depending on risk and sexual factors. These results support the usefulness of this new
vaccine to be extensively applied in control campaigns to effectively interrupt the T. solium transmission.
83
Development of the Life Cycle of Taenia pisiformis Using Golden Hamster as the Definitive Experimental Host. E. TORAL-BASTIDA*, P.J. MARAVILLA-CAMPILLO, A. GARZA-RODRÍGUEZ, R. GARCIACORTES, P. PALOMARES-PÉREZ and L. FERNANDEZ-MAYA, Hospital General “Dr. Manuel Gea
González,” México DF, G. AVILA-RAMIREZ and A. FLISSER, Facultad de Medicina, UNAM, México
DF, México.
We reproduced the life cycle of Taenia pisiformis in the laboratory, using rabbits as natural intermediary
hosts and golden hamsters as experimental definitive hosts. T. pisiformis eggs were obtained from naturally infected dogs, their viability was evaluated by six techniques, and 1,500 eggs were used to infect
each rabbit. After seven to 10 weeks, cysticerci were recovered and used to infect immunosuppressed
hamsters; T. pisiformis cysticerci from naturally infected rabbits also were used to infect hamsters. The
average viability values obtained were: propidium yodine (PY) 79%, trypan blue (TB) 58%, neutral red
(NR) 47%, oncosphere activation (OA) 8%, and 0% for MTT. At necropsy, 89 cysticerci (41 viable and
48 calcified) were obtained from 25 of the 51 rabbits infected. To obtain adult parasites, female hamsters
were infected with one to three morphologically intact cysticerci obtained from experimental infections
and kept immunosuppressed by injection of methyl prednisolone acetate each 14 days; feces were sieved
to follow up infections, no gravid proglottids were found, and, during necropsy performed at four to
eight weeks post-infection, no tapeworms was recovered. Instead, when cysticerci from two naturally
infected rabbits were used to infect six immunosuppressed female hamsters, proglottid release started
after 21 days and 16 weeks post-infection, and one gravid T. pisiformis measuring 21 cm was recovered at
necropsy; egg viability was 98% by PY, 70% by TB, 68% by NR and 0% by OA. Five rabbits were
inoculated with 1,500 eggs each and at necropsy eight cysticerci (six alive and two calcified) were found.
Our results indicate that gravid adult T. pisiformis tapeworms develop in immunosuppressed hamsters if
cysticerci come from natural infections. Propidium yodide and trypan blue apparently are the best assays
to evaluate viability of oncospheres since they are simple to perform, easy to interpret and gave good
correlation with infection.
84
Viability of Trichinella spiralis Recovered in Meat Submitted to Different Conditions of Handling and
Conservation. M. MEDINA-LERENA*, A. RAMÍREZ-ALVAREZ, E. PÉREZ-TORRES, C. PACHECOGALLARDO and S. RUVALCABA-BARRERA, Laboratorio de Medición Paraclínica, Centro Universitario
de Ciencias Biológicas y Agropecuarias, Zapopan Jalisco, and J.L.A. DE LA ROSA, Laboratorio de
Helmintos Tisulares, Instituto de Nacional de Diagnóstico y Referencia Epidemiológicos, México DF,
México.
Trichinellosis is a worldwide parasitic zoonoses caused by the muscle larvae (ML) of the nematode
Trichinella spiralis. Transmission involves both domestic and wild animals. Human beings can be infected
by the ingestion of raw or insufficiently cooked meat containing the ML. The procedures of cure, flavor,
drying, refrigeration and freezing of meat to human consumption do not guarantee the complete destruction of T. spiralis. In México, the government Norm, NOM-194-SSA1-2004, defines that the pig
meat should be free of Trichinella spiralis to be considered apt for human consumption. Thus, the aim of
this work was to determine the viability of T. spiralis ML recovered from pork meat subjected to different
handling conditions and conservation. Three male pigs three months old were infected experimentally by
oral with 5,000 ML. At day 105 post-infection, when pigs weighted 90 kg and specific antibodies were
detected by ELISA, the animals were sacrificed; the diaphragm, masseters and tongue were obtained and
pooled, then separate portions of 50 g were used for treatments. Handling and conservation procedures
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were (1) freezing by 15 or 30 days at -18°C or -20°C; (2) refrigeration for 105 days at 4°C or 0°C; (3)
drying carried out in an oven for 24 hours at 60°C or 57°C, then submitted to 4°C by 15 or 30 days; (4)
two commercial products, “Doña Chonita” and “Doña Paula,” were used to flavor the meat, which was
then submitted to 4°C for 105 days; and (5) cure were made by 3% brine during 24 hours, then submitted to 4°C or 0°C for 105 days. After treatment, the meat was digested with 1% pepsin-HCl solution to
recover the ML and naïve mice were infected with 50 ML. After 40 days post-infection, the diaphragms
were obtained and ML were detected by trichinoscopy. No larvae were recovered of mice infected with
larvae recovered from meat freezing or drying.
85
Efficacy of Three Doses of a Mexican Strain of Duddingtonia flagrans Chlamydospores Against haemonchus Contortus Larvae in Sheep Faecal Cultures. N.F. OJEDA-ROBERTOS*, FMVZ, Universidad
Autónoma de Yucatán, Mérida, Yucatán, P. MENDOZA-DE-GIVES, CENID-PAVET, Instituto Nacional de
Investigación Agricola y Pecuaria, J.F. TORRES-ACOSTA, A. AYALA-BURGOS and A.J. AGUILARCABALLERO, FMVZ, Universidad Autónoma de Yucatán, Mérida, Yucatán, México.
Anthelmintic-resistant Haemonchus contortus is becoming a common feature in tropical and sub-tropical
areas of the world. Alternative methods for the control of these nematodes are sought. The objective was
to evaluate the efficacy of three doses of Duddingtonia flagrans chlamydospores against H. contortus
infective larvae from sheep faecal cultures. Twelve male hair sheep, infected with H. contortus, were
divided into four groups of three animals each. Groups 1, 2 and 3 received doses of 1 x 106, 2.5 x 106
and 5 x 106 chlamydospores per kg body weight. Animals received their doses on seven consecutive days.
The fungal material was dosed orally in a molasses–oat mix. Animals in group 4 were the control group.
Faeces were collected from rectum of sheep on days 2, 4, 6, 8 and 10 post-inoculation of fungal chlamydospores. Four faecal cultures from every sheep were prepared per day in a Petri dish. Each faecal culture
(experimental unit) was incubated for eight days. After the incubation period, infective larvae were
harvested from the faecal cultures (Baermann technique). The estimation of the number of recovered H.
contortus infective larvae was obtained by counting the number of larvae in 10 aliquots of five µl. Animals
in group 1 had a maximum larvae reduction on day four post-administration (80.5%). Animals in group
2 had a maximum larvae reduction of 91% on day two and 79.3% on day six. A variable response in the
larvae reduction was observed in group 3 (maximum reduction of 72.7% at the fourth day). The three
D. flagrans chlamydospore doses showed similar reduction percentages. Therefore, the lower dose (1 x
106 chlamydospores per kg of body weight) was considered sufficient to obtain a satisfactory larvae
reduction in faecal cultures. (Trial funded by SAGARPA-CONACYT-COFUPRO 12441.)
86
Infection Dynamics of Ectoparasites During the Hatchery of Hybrid Tilapia “Pargo-UNAM.” M.D.
PÉREZ-FOSADO*, M.I. JIMÉNEZ-GARCÍA, M. GARDUÑO-LUGO, G. MUÑOZ-CÓRDOVA and M.D.
CASTAÑEDA-CHÁVEZ, División de Estudios de Posgrado e Investigación y Centro de Estudios, Investigación y Extensión, Instituto Tecnológico de Boca del Río, Veracruz, México.
Although the economic and social potential of tilapia aquaculture in México, until now, it is scarce the
knowledge about the infection behavior of parasites in such activity. According to tilapias examination in
several farms in Veracruz State, Trichodina and the monogeneans, Gyrodactylus sp. and Cichlidogyrus spp.,
are relatively frequent and abundant parasites; however, there is no information about possible effects of
such parasites in the tilapia growth. Therefore, we studied experimentally the effect of ectoparasite
infection dynamics in the growth of fry tilapias (0.3 ± 0.1 gr) during a period of 90 days. Tilapias were
set in four tanks of 1,000 L: control (without parasites) and treatment (with parasites), with one replica
each one (90 fishes/tank). Before the experiment, 20 fishes were examined and no parasites were found.
Physicochemical water features were maintained in similar values. To ensure that every treatment contained infected fishes, fry Oreochromis niloticus parasitized with Trichodina, Gyrodactylus and Cichlidogyrus
were introduced during two weeks in both tanks, in small cages, in order to expose to the tilapia PargoUNAM to the infective forms of the parasites. All the material was disinfected in control systems, even
though control fishes were colonized by parasites, therefore, we decided to apply a treatment with
formalin (1:4000) for 30 minutes every two weeks. The monitoring of the infection dynamics was made
every two weeks, checking 12–15 fishes randomly chosen from each tank. Each examined host was
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measured and weighed, parasite were censed to evaluate the infection intensities. At the end of the study,
one way ANOVA analysis showed that there were no significant differences F3,287 = 1.36, p = 0.25
between the final weight between control (23.8 ± 10.9 gr.) and treatment tanks (22.7 ± 13.9 gr.), even
though fishes from treatments had significantly more parasites than those of the controls: Gyrodactylus
sp. F3,287 = 7.67, p < 0.0001; Cichlidogyrus F3,287 = 4.85, p < 0.003; and Trichodina sp. F3,284 = 6.72, p
< 0.0002.
87
Taenia solium: Active Transmission of Pig Cysticercosis in Sierra de Huautla, Morelos. J. MORALES*, J.J.
MARTÍNEZ, N. PEÑA, Facultad de Medicina Veterinaria y Zootecnia, UNAM, Ciudad Universitaria,
México DF, V.M. MAZA, Secretaria de Desarrollo Agropecuario, Departamento del Programa de Salud
Animal, N. VILLALOBOS, A. ALUJA, Facultad de Medicina Veterinaria y Zootecnia, UNAM, Ciudad
Universitaria, México DF, A. FLEURY, Instituto Nacional de Neurologia y Neurocirugia Manuel Velasco
Suarez, México DF, G. FRAGOSO, C. LARRALDE and E.L. SCIUTTO, Instituto de Investigaciones
Biomedicas, UNAM, Ciudad Universitaria, México DF, México.
Taenia solium is a parasitic disease that frequently affects human health and rustic porciculture in México.
This study was designed to determine pig cysticercosis prevalence in 16 rural communities of “Sierra de
Huautla” in the State of Morelos, México, to design a strategic control program in this area. In a first
survey, a prevalence of 13% was determined in a total of 562 pigs by tongue inspection from the 1,500
pigs estimated in the area. Absence of latrines and the degree of confination were found related to
cysticercosis. Cyticercotic pigs exhibited a significant lower weight than those not infected. In a second
survey, 1,081 piglets of three to four months of age were inspected and a frequency of 6.2% was determined. These data indicate that almost half of the pigs infected acquired cysticercosis early during their
lives. The relevance of pregnancy, castration and localization of the pigs in the community were determined. Overall, this information will be of usefulness for the design of a control program with major
impact to effectively interrupt the infection in these communities.
88
Phylogenetic and Biogeographical Relationships of Several Populations of Rhabdias Sp. (Nematoda),
Parasite of Leptodactylus melanonotus (Anura) from México. E.A. MARTÍNEZ-SALAZAR* and V. LEÓNRÈGAGNON, Lab. Helmintología, Departamento de Zoología, Instituto de Biología, UNAM, México
DF, México.
Ten of about 54 species of the cosmopolitan genus Rhabdias Stiles and Hassall, 1905 are recorded in
México (R. americanus, R. ranae, R. füelleborni; R. cf. elegans; R. cf. tobagoensis; R. savagei, R. lamothei,
and R. leonae; and two species considered originally as Palaearctic: R. cf. sphaerocephala and R. cf.
fuscovenosa) as parasitizing the lungs of several species of amphibians and reptiles. The identification of
Rhabdias is complicated principally due to their morphological similitude and poor knowledge of its host
specificity; however, the molecular sequences of mitochondrial DNA (e.g., cytochrome oxidase subunit 1
(cox1)) or rDNA (ITS-1) provide a powerful tool to differentiate related species. The phylogenetic and
biogeographical relationships of several populations in México using partial sequences of cytochrome
oxidase I, and cytochrome b of mtDNA (964 pb), and partial sequences of 18S and 28S, complete
sequences of ITS-1, 5.8S, and ITS-2 of rDNA (~2,000 pb) from several samples the Rhabdias of
Leptodactylus were analyzed (including Rhabdias sp, R. leonae and Entomelas floresvillelai as the outgroup).
Maximum parsimony analysis was performed using PAUP. We obtained eight equally parsimonious trees
(CI = 0.86). Two clades of Rhabdias from Leptodactylus were revealed by the phylogenetic analyses.
These included populations from Pacific and Gulf Slopes of México, respectively, showing high host
preference. Richness of amphibians and reptiles in México suggests the existence of several species of
Rhabdiasidae still waiting to be discovered. (Supported by NSF DEB-0102383; ASP Willis A. Reid, Jr.
Student Research Grant 2006.)
89
Genetic Variation Among Populations of Phyllodistomum lacustri (Loewen, 1929), Parasite of Ictalurids
in North America, Using Sequences of the 28s rRNA Gene. R. ROSAS-VALDEZ*, Instituto de Biologia,
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UNAM, A. CHOUDHURY, St. Norbert College, De Pere WI, USA, and G. PÉREZ-PONCE DE LEÓN,
Instituto de Biologia, UNAM, Mèxico.
Phyllodistomum lacustri is a digenean commonly found in ictalurids in North America. The distributional
range of this species extends from Canada to Central México. This species is distinguished easily by its
ridges (crenulations) in the hindbody margin. Specimens of P. lacustri were collected from five locations:
Rio Bravo (Grande), Tamaulipas State, San Juanico Reservoir, Michoacán State, and Rio Nazas,
Durango State (México), Nemaha River, Nebraska (U.S.A.), and Assiniboine River, Manitoba (Canada).
The objective of this study is to analyze the genetic variation of P. lacustri along its distributional range
by using partial sequences of the 28S ribosomal RNA gene. Sequences were obtained also for two other
species of Phyllodistomum (P. staffordi from La Salle River, Manitoba and P. brevicaecum from Broken
Head River, Manitoba), as well as one species of gorgoderid (Gorgoderina sp. from Lake Catemaco,
Veracruz). The sequences of individual specimens of P. lacustri from the Assiniboine, Nemaha and Bravo
Rivers were identical; only individuals corresponding with endemic hosts in Central México (Ictalurus
dugesi and Ictalurus sp.) showed some level of genetic variation with respect to the other three populations, although this variation is very low. In our analysis, P. lacustri is the sister species of P. staffordi, with
P. folium as the sister taxa of these two, and P. brevicaecum as the sister taxa to all of them. Both P. lacustri
and P. staffordi are parasites of ictalurid catfishes, and they show some morphological differences, although the presence of crenulations (inconspicuous in P. staffordi) in the hindbody margin may represent
a synapomorphy. Some authors have proposed that P. lacustri is a junior synonym of P. staffordi. A more
detailed analysis in which more species of Phyllodistomum are included would corroborate or reject this
proposal.
90
First Record of Salsuginus angularis (Mueller, 1934) Beverly-Burton, 1984 (Monogenea: Ancyrocephalinae) Parasitizing Goodeinae Fishes (cyprinodontiformes: Goodeinae) Endemic to México. C.A.
MENDOZA PALMERO* and G. SALGADO-MALDONADO, Laboratorio de Helmintología, Departamento de Zoología, Instituto de Biología, UNAM, México DF, México.
The freshwater fish of the subfamily Goodeinae include 36 species endemics to Central México. Some of
these species have been studied for helminth parasites. However, studies about the monogenean fauna,
which parasitize these fish, are scare. In recent studies, we have identified Salsuginus angularis as parasitizing goodeinae fish endemic to México. This species had been registered previously as Fundulus diaphanus from North America, and we registered it for the first time to the family Goodeidae. The objective of
this work was to carry out a taxonomical survey of dactylogyrids, such as collecting of goodeinae fish,
comparing the morphology of its sclerotized structures with other species of Salsuginus, and providing
host and locality records. We registered S. angularis as parasitizing 12 goodeinae species of 10 genera in
Central México. The presence of this monogenean on endemic fish of México could suggest an evolutionary history in common between Fundulidae and Goodeidae, like recent phylogenetic studies of
Cyprinodontiformes have suggested.
91
Entomological Indexes of Triatoma dimidiata (Hemiptera: Reduviidae: Triatomine) to Assess Risk
Transmission in Rural San Pedro Chacabal, Motul, Yucatán, México. I.J. MAY-CONCHA*, S.J.
CARBALLO-GONZÁLEZ, Instituto Tecnológico de Conkal, Conkal, Yucatán, A. POLANCORODRÍGUEZ, Departamento de Medicina Social y Salud Pública, Centro de Investigaciones Regionales “Dr. Hideyo Noguchi,” Universidad Autónoma de Yucatán, Mérida, Yucatán, F.J. ESCOBEDOORTEGÓN, H.A. RUIZ-PIÑA, M.A. BARRERA-PÉREZ and E.A. REBOLLAR-TÉLLEZ, Departamento de
Enfermedades Infecciosas y Transmitidas por Vector, Centro de Investigaciones Regionales “Dr. Hideyo
Noguchi,” Universidad Autónoma de Yucatán, Mérida, Yucatán, México.
Trypanosoma cruzi is the causative agent of Chagas Disease in Latin America. The disease is endemic in
México, including the Yucatán Peninsula. In Yucatán, there have been several studies on clinical, reservoir
hosts, vectors and parasite strains. However, the fully epidemiological extend to which Chagas disease
occurs in Yucatán, especially in rural and poor communities, is unknown. With this in mind, we selected
a community to assess the risk of T. cruzi transmission to inhabitants. To achieve an empowerment of
people towards the disease, we imparted several workshops in the elementary school and afterwards we
94
ABSTRACTS
began the collection of bugs in a group of selected households of the community. Sampling of triatomines was carried out weekly from May 2006 to March 2007. In addition, we also have placed resting/
hiding traps made out of milk and soft drink containers, which were placed in the peridomestic and
domestic environments. Furthermore, once per month we carried out night captures (1800 to 2100 h) of
bugs in a selvatic ecotope 1.3 km away from the houses. Night catches were carried out using a blank
cloth (1.5 x 1.5 m) suspended from branches of trees, illumination to the cloth was provided by one 6-v
fluorescent lamp. Overall, we caught 191 triatomines as follows: 147 intra-domestic, 24 peri-domestic,
and 20 sylvatic. The majority of bugs captured were adults, females (57.9 %, n = 106) being more
abundant than males (42.2%, n = 77). We have found evidence of colonization by the finding of eight
nymphs of T. dimidiata. Infection rate was found low as revealed by parasitological examination (4.76%,
n = 42) of faeces and PCR analysis of mid and hindguts (0%, n = 36). The abundance of T. dimidiata
was found highest during August and September, which taken together represented 64.4% of all collected bugs so far. The lowest abundance was during December, January and February, which represented
together only the 4.2%. The analysis of spatial distribution of bugs within the community has been
shown to be uneven among the selected premises.
92
PCR Analysis of Infection Rates of Sandfly Species (Diptera: Psychodidae: Phlebotominae) from
Calakmul, Campeche, México and their Putative Role as Vectors of Leishmania mexicana (Kinetoplastida: Trypanosomatidae). A. PECH-MAY*, F.J. ESCOBEDO-ORTEGÓN, Departamento de Enfermedades Infecciosas y Transmitidas por Vector, Centro de Investigaciones Regionales “Dr. Hideyo
Noguchi,” Universidad Autónoma de Yucatán, Mérida, Yucatán, M. BERZUNZA-CRUZ, Departamento
de Medicina Experimental, Facultad de Medicina, UNAM, México DF, and E.A. REBOLLAR-TÉLLEZ,
Departamento de Enfermedades Infecciosas y Transmitidas por Vector, Centro de Investigaciones
Regionales “Dr. Hideyo Noguchi,” Universidad Autónoma de Yucatán, Mérida, Yucatán, México.
Leishmania mexicana is the main parasite causing cutaneous leishmaniasis (CL) in the Yucatán Peninsula.
In Campeche, the disease is endemic and the sandfly Lutzomyia olmeca olmeca has hithertho been incriminated as the main vector, although recent studies suggest that other species may act as vectors as well.
Based on recent data of human cases of CL, we selected two endemic villages to undertake sandfly
catches. The villages were Dos Lagunas Sur and Ejido La Union 20 de Junio, Calakmul, Campeche.
Catches were made from November 2005 to February 2006, a period that previously has been documented to include the transmission season of Le. mexicana. Sampling was carried out using a Shannon
trap and rodent-baited Disney traps. Specimens were preserved in ethanol in Eppendorf vials. Later, in
the laboratory in Mérida, the heads of female bodies were dissected and used for sandfly identification,
while the remaining bodies were kept frozen until their analysis by PCR. In Dos Lagunas Sur, 892
specimens of nine species were caught, whereas in Ejido la Union 20 de Junio, 1,354 specimens of nine
species were collected. In Dos Lagunas Sur, the most abundant sandfly species were Lu. panamensis
(39.57%), Lu. olmeca olmeca (29.93%) and Lu. shannoni (11.88%), whereas in Ejido la Unión 20 de
Junio, the most abundant species were Lu. olmeca olmeca (27.4%), Lu. panamensis (24.29%), Lu. cruciata
(20.53%) and Lu. shannoni (17.94%). The highest biting rate of female sandflies was recorded during
December. of the 769 sandfly females analysed by PCR, we found 27 positive females (3.51%). The
highest infection rate (5.30%) was found in Ejido La Unión 20 de Junio. Positive females were Lu.
olmeca olmeca, Lu. shannoni, Lu. panamensis, Lu. cruciata, and Lu. ylephiletor. With this study, we confirm
the role of Lu. olmeca olmeca as a primary vector of Le. mexicana as well as the suspected role of Lu.
shannoni, Lu. panamensis, Lu. cruciata and Lu. ylephiletor. Further studies on vector competence are
required to fully incriminate those species.
93
Dexamethasone and PGE2 Modulation of the Immune Response in Fat Body and Midgut of Anopheles
albimanus. F.L. GARCÍA-GIL DE MUÑOZ*, Department of Experimental Pathology, CINVESTAV-IPN,
México DF, J. MARTÍNEZ BARTNECHE, H. LANZ MENDOZA, M.H. RODRÍGUEZ LÓPEZ, CISEINational Health Public Institute, Cuernavaca Mor, and F.D. HERNÁNDEZ-HERNÁNDEZ, Department
of Experimental Pathology, CINVESTAV-IPN, México DF, México.
95
ABSTRACTS
Studies in lepidopteran and hemipteran insects have involved prostaglandins (PGs) in the regulation of
insect immune system. In mosquito vectors, an understanding of PGs participation in the modulation of
immune system could be useful to design novel strategies for malaria control. In this work, PGE2 was
identified and measured in midgut and fat body cultured in vitro of Anopheles albimanus (a major vector
of malaria in México), using an specific enzyme immunoassay (EIA) and the effects of follow PGs
synthesis inhibitors described: Dexamethasone, a Phospholipase A2 inhibitor; and Ibuprofen, an Cyclooxygenase I- II inhibitor. The results demonstrated that an eicosanoid biosynthesis system is present in
An. albimanus and that the system responds, in cultured midguts, to the presence of Gram-positive
bacteria (Micrococcus luteus) and Gram-negative bacteria (Klebsiella pneumoniae). These observations
indicate that PGE2 could be an important regulator of the immune response to bacterial invasion. RTPCR experiments evaluating the production of mRNA for three antimicrobial peptides, which are
described for forts time in this specie, attacin, cecropin and gambicin-homologue in cultured fat body
and midgut, showed a decrease at 30′ of treatment with dexamethasone and production was restored by
PGs precursor Arachidonic Acid (AA). In other experiments adding PGE2 to cultured organs cecropin
mRNA increased at 30′
and, in contrast, attacin and gambicin-homologue mRNA production decreased. This is the first
demonstration that mosquitoes immune responses are modulated by a physiological system, including
PGs biosynthesis. Molecular mechanisms of regulation by PGs should involve different receptors,
including coupled G-receptors or intracellular receptors, as those used by steroid hormones as PPAR γ
molecules, which has been proposed in other models, and research will be oriented to answer these
issues.
94
The Effect of the Prostaglandins on the Proteolitic and Bactericide Activities of the Midgut of Aedes
aegypti Mosquito. M.G. HERNÁNDEZ-ESTRADA*, F.D. HERNÁNDEZ-HERNÁNDEZ, F.L. GARCIA-GIL
DE MUÑOZ, Universidad Simón Bolivar y CINVESTAV-IPN, Lab. Entomología Molecular, Dpto.
Patología Experimental, Cd. México DF, H. LANZ-MENDOZA and M.H. RODRÍGUEZ, Centro de
Investigación Sobre Enfermedades Infecciosas e Instituto Nacional de Salud Pública, Cuernavaca,
Morelos, México.
Aedes aegypti mosquitoes are efficient vectors of viral diseases including Dengue. Transmission occurs
when female mosquitoes feed with blood, because during probing. mosquito injects saliva (transmitter
vehicle). Mosquitoes present different defense mechanisms against infectious agents: the production of
enzymes, serine proteases type (24–36 kDa) involved in digestion of food, and activation of defense
mechanisms like melanization and encapsulation; and the synthesis of antimicrobial peptides (4–24
kDa), small proteins that eliminate invader microorganisms modifying the permeability of their cellular
membrane. In mammals, prostaglandins, lipidic molecules derived from arachidonic acid, coordinate the
responses of the immune system, but in insects, their presence and activity is scarcely described. Objective: To study the immune response of Ae. aegypti, the proteases activity, and the bactericide effect on
Serratia marscesens (gram-) and Micrococcus luteus (gram +) of midgut extracts of adult females, which
was measured and compared with the response in presence of prostaglandine E2 (PGE2) or its synthesis
inhibitor Dexamethasone (Dex). Material and Methods: To observe proteases activity, zymographies
were conducted in acrylamide gels copolimerized with gelatin. Bactericide activity was evaluated by a
modification of the routine zone of inhibition method. Total midgut proteins were analyzed by PAGESDS and one differential protein was identified by MALDI-TOF. Results: The proteolytic activity of the
midgut extracts decreased in presence of Dex. The antimicrobial activity, which was measured by the size
of the inhibition haloes, was affected, too, by the treatment with Dex. On the other hand, the proteins
pattern observed by PAGE-SDS changed with the treatment of PGE2. Finally, one protein of 37 kDa
with homology to one Dihydrodiol dehydrogenasa, disappear of the tissue by Dex effect. Conclusions:
The prostaglandins modulate several immunological activities in the midgut of Aedes mosquito. This
information might be useful to design new strategies of Dengue control.
95
Generation of EhGEF1 Protein Mutants From Entamoeba histolytica. N.A. HERNÁNDEZ-CUEVAS*,
CINVESTAV-IPN, Dept. of Molecular Biomedicine, México DF, A. ROJO-DOMÍNGUEZ, UAM-Cuaji96
ABSTRACTS
malpa, M.D. ALMARAZ-BARRERA and M.Á. VARGAS-MEJIA, CINVESTAV-IPN, Dept. of Molecular
Biomedicine, México DF, México.
The Rho family GTPases are molecular switches that are involved in the majority of actin-dependent
processes such as those related to migration, actin cytoskeleton, morphogenesis, phagocytosis, cell
polarity, cell cycle progression and gene expression. The Rho GTPases are low molecular weight proteins
that have a cycle of two states: one inactive GDP-bound and the other active GTP-bound. The Rho
family GTPases’ cycle of activation and inactivation is regulated by the GEF proteins or Dbl family
guanine nucleotide exchange factors. These proteins have an important role as positive regulators of the
Rho proteins. The GEF proteins are able to bind to their inactive target GTPase bound to GDP and to
promote GDP disassociation so that the latter can be activated in GTP binding. Recently, our study
group reported the first GEF in parasites, the EhGEF1 protein from Entamoeba histolytica: this protein is
able to promote the guanine nucleotide exchange on the EhRacG and EhRho1 GTPases of amoeba. In
this study, we produced models of the EhGEF1–EhRacG and EhGEF1–EhRho1 complexes. Through
mutation in silico, we estimated the contribution of the residues of the interface region of both complexes. We identified two EhGEF1 residues not preserved among the members of the Dbl family, which
are important for the selective activity on EhRacG, since by mutating them with alanine, the guanine
nucleotide exchange activity in vitro on EhRacG, and not on EhRho1, was affected. Moreover, we were
able to obtain three candidate residues that could dictate selectivity on the EhRho1 GTPase.
96
Protein Carbonylation in Trypanosoma cruzi during Differentiation in vitro. I. MARTÍNEZ* and B.
ESPINOZA, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, Ciudad
Universitaria, México DF, México.
Protein carbonylation is a natural process that occurs in all cells to label proteins that will be degraded in
the proteasome. This process can be increased by oxidative stress, starving and aging. The phenomenon
of protein carbonylation has not been studied in T. cruzi, the causal agent of Chaga’s Disease, and it is
unknown if there is an increase in protein carbonylation during differentiation of the parasite in vitro.
The aim of this work was to determine the carbonylated proteins in epimastigotes of T. cruzi during the
differentiation process from epimastigotes to tripomastigotes in vitro. Epimastigotes of Silvio (T. cruzi
major group I) and Cl Brener (T. cruzi major group II) strains were cultured in LIT medium starting
with five million of parasites per milliliter. Parasites were counted and collected at 2, 4 and 10 days of
culture. Cellular pellets were lysate in buffer (Hepes 10 mM, SDS 6%). Total protein was quantified by
DC protein assay (Bio-RAD) and 10 micrograms of protein was separated by SDS-PAGE and transfered
to the nitrocellulose membrane. Carbonylated proteins in the membrane were detected using Oxiblot Kit
(Chemicon, USA). Seven proteins ranging 40–90 KDa were carbonylated at early log phase (2 days),
middle log (4 days) and stationary (10 days) culture in both strains. No changes in number of carbonylated proteins during differentiation in vitro was observed. However, the levels of carbonylation in T.
cruzi were higher than the observed in other microorganisms such as E. coli or Leishmania mexicana.
High levels of carbonylated proteins observed in T. cruzi are maintained in the presence of 10% and 20%
of fetal bovine serum, indicating that the protein carbonylation observed was not caused by nutritional
stress in the culture. We concluded that T. cruzi have higher levels of carbonylated proteins than other
microorganisms and that the number of carbonylated proteins does not change during the differentiation
process.
97
Identification of a Cyclooxygenase–like Enzyme in Leishmania mexicana Promastigotes. J. DIAZGANDARILLA*, J.L. ROSALES-ENCINA, A. ANGEL and P. TALAMÁS-ROHANA, Departamento de
Patologia Experimental, CINVESTAV.
Leishmania sp. are trypanosomatid parasites that infect humans and mammals. Infections with these
parasites are associated with an overproduction of arachidonic acid (AA) metabolites. The cyclooxygenases 1 and 2 (COX-1/2) reaction convert AA to PGG2 and PGH2 as intermediaries used for the generation of prostaglandins (PGs) such as PGE2, PGF2α; and PGD2. PGs influence the pathogenesis of the
infection, favoring a Th2 type response and suppressing the Th1 type response in the infected host, as
well as inhibiting macrophages response against the parasite. The aim of this study was to identify and
97
ABSTRACTS
characterize a COX-like activity in L. mexicana promastigotes by means of a chemiluminescent assays to
measure COX activity. Enzymatic activity is represented as Relative Light Units (RLU) at integration
times of 300 ms. Enzymatic reactions on 96 well microtiter plates were recorded in a luminometer.
Enzymatic activity in total extracts was 2200 RLU. This enzyme showed its optimal activity at a pH of
7.5, and in order to see whether the enzyme was an inducible one, assays were performed with total
extracts from parasites cultivated in the presence of 33 µM of AA. Under this condition, there was a 2.6fold increase in the enzymatic activity in comparison with total extracts from parasites cultivated without
AA. COX-1 and 2 are membrane-bound enzymes; therefore, a fractionation procedure was followed in
order to obtain soluble and membrane fractions (SF, MF). Results showed that 27.7% of activity was
associated with SF and 72.3% with MF. These results suggest that L. mexicana displays a COX-like
activity, which could play a major role in the pathogenesis and immune evasion mechanisms.
98
Characterization of Taenia solium Cysticerci Microsomal Glutathione S-transferase Activity. G. NAVA*
and A. PLANCARTE, Departamento de Microbiología y Parasitología, Facultad de Medicina, UNAM,
México DF, México.
Glutathione S-transferase activity has been shown to be associated firmly with the microsomal fraction of
Taenia solium. Activity was still observed after washing of the microsomes, and after carrying out procedures that release loosely bound material from membranes. Electron microscopy and subcellular enzyme
markers criteria indicate the high purity of the microsomal fraction that presents the glutathione Stransferase activity. T. solium microsomes were solubilized using Triton X-100 at a similar concentration
as used for solubilize integral microsomal proteins. This procedure proved necessary to obtain enzymatic
activity. Neither N-ethylmaleimide nor iodoacetamide activated the parasite microsomes, as also observed
for Escherichia coli, Synechocystis sp., Arabidopsis thaliana and the frog Xenopus leavis. In order to characterize this parasite enzyme activity, several substrates and inhibitors were used. The optimum activity for
microsomal glutathione S-transferase was found at pH 6.6, and had a specific enzyme activity of 0.9, 0.1,
0.067, 0.03, 0.05 µmol min-1 mg-1 the substrates 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4nitrobencene, 4-hydroxynonenal, 2,4-hexadienal and trans-2-nonenal respectively. No activity was
observed with ethacrynic acid, H2O2and cumene hydroperoxide. T. solium microsomes were inhibited by
Cibacron Blue (IC 50 µM), sulfobromophthalein (IC 50 53.5 µM), triphenyltin choride (IC 50 8.0 µM)
and Rose Bengal (IC 50 14.3 µM) and it was possible to establish the simple inhibition system for each
inhibitor. These results indicate that the T. solium microsomal glutathione S-transferase is different from
the parasite cytoplasmic enzymes catalyzing similar reactions. (Work supported by a grant from the
UNAM [PAPIIT-IN201906-3]).
99
Identification of Excretion/Secretion Products during Evagination and in vitro Degeneration of Cysticerci of Taenia solium. F. MENDLOVIC* and A. FLISSER, Departamento de Microbiología y Parasitología, Facultad de Medicina, UNAM, México DF, México.
The ability of cysticerci to evaginate depends on the regulation of expression of different proteins. In
addition, neurocysticercosis remains asymptomatic for long periods while the parasite is intact; however,
clinical symptoms are thought to be a result of degenerating cysts, suggesting the presence of immunomodulatory products synthethized by the live parasite. Identification of molecules involved in both these
phenomena will bring some insight into the mechanisms necessary for establishment and pathogenesis of
T. solium. We characterized the parasite’s proteome, including excretion–secretion products of cysticerci
incubated in the presence of trypsin and praziquantel, which constitute in vitro models of evagination and
degeneration, respectively. Protein patterns of evaginated and degenerating cysticerci were compared to
that of controls at different times before, during and after induction of evagiantion or degeneration.
Preliminary results of one-dimensional electrophoresis show a ~43 kDa band in cysticerci induced to
evaginate, which is absent in the controls. The band is present after 15 minutes, even though, macroscopically, the parasites have not evaginated; this occurs after 90 minutes. Two-dimensional gels of both
the proteome and excretory–secretory products will be generated to identify differentially expressed
proteins that will be submitted to mass spectrometry. The T. solium genome is being characterized by
98
ABSTRACTS
Laclette et al. and, together with other available databases, will help us identify proteins involved in both
evagination and degeneration of cysticerci, which are crucial in the pathology associated with T. solium.
100
Kinetic Determinations to Recombinant Glutathione Transferase of 26.5 kDa From Taenia solium. A.
TORRES-RIVERA* and A. LANDA, Departamento de Microbiología y Parasitología, Facultad de
Medicina, UNAM, México DF, México.
Taeniosis and cysticercosis caused by Taenia solium are not minor diseases and actually are widely distributed. In fact, WHO and FAO have developed a control plan for them. Cysticercosis represents the main
cause of neurological illness with parasitic origin, and part of epileptic seizures is associated to it, generating a great morbility. Despite of diverse interventions using vaccines and chemotherapy with antihelminthics to erradicate those diseases, until now there have been no conclusive advances. Therefore, new
ways are necessary to deal with the problem, such as developing inhibitors against essential parasitic
enzymes. Our choice is focused toward detoxification metabolism. Cytosolic glutathione transferases
(GST, E.C. 2.5.1.18) are a versatile family of enzymes that are part of the second phase of detoxification;
they catalyze conjugation of glutathione (GSH) to a wide range of electrophilic compounds. In T. solium,
two dimeric GST with a monomeric molecular mass of 25.5 and 26.5 kDa have been identified. The
recombinant GST26.5 kDa (GST26.5r) was expressed, purified by affinity chromatography and its
kinetic parameters determined according to Habig (1981, Methods in Enzymology). Enzyme activity was
determined using 1-Chloro-2,4-nitrobenzene (CNDB) as a universal substrate and other compounds like
ethacrynic acid, bromosulfophtalein, cumene hydroperoxide, and alkenals were used as class markers. The
optimum activity for the GST26.5r was found at the pH range of 6.5–8.5 and between 4–50°C. Kinetic
results showed that enzyme had a Vmax = 51.5 µM/minmg and Km = 1.1 mM for CDNB. Activity
analysis with the class markers showed a hybrid behavior between mu and alpha classes Also, kinetic
analysis suggested that catalytic mechanism is influenced by a cooperativity process.
101
Iron Modulates the Differential Expression of Proteinases in Trichomonas vaginalis. L.D. RAMÓNLUING*, L. ÁVILA-GONZÁLEZ and R. ARROYO, Depto. Patología Experimental, CINVESTAV-IPN,
México DF, México.
The expression, proteolytic activity, and surface location of many Trichomonas vaginalis CPs are regulated
differentially by iron. Recently, in the T. vaginalis genome project, 48 genes encoding papain-like cysteine
peptidase were reported. In two-dimensional (2-D) zymograms, however, 23 spots with proteolytic
activity between 23 and 110 kDa and pI between 4.5 and 7.0 have been detected. The aim of this work
was to study the differential expression of peptidases to identify the iron up- and down-regulated trichomonad CPs. Total protein and proteinase samples were separated by isoelectric focusing and used for
the second dimension on SDS-PAGE acrylamide gels or gels co-polymerized with gelatin. Approximately
51 and 149 spots were observed in total protein extracts from normal, grown parasites in the silver- and
Coomassie blue brilliant-stained 2-D gels, respectively. In contrast, only 25 spots were observed in the
total proteinase extracts in the 2-D silver-stained gels. Interestingly, a similar proteolytic pattern was
observed in the 2-D zymogram. These data suggest that the silver-stained spots may correspond to
proteinases. To confirm this, we analyzed the spot #16 by LC-MS/MS. The peptide sequence obtained
from this spot identified it as a novel cathepsin L-like CP. Differential 2-D zymograms and silver-stained
patterns of proteinase extracts from parasites grown in different iron concentrations showed 15 and 22
spots at low- and high-iron concentrations, respectively. These results confirm that iron controls the
differential expression of T. vaginalis proteinases. This strategy will be useful to separate and identify by
mass spectrometry the distinct trichomonad peptidases that are expressed in the parasite.
102
Analysis of PKC β-like from Giardia duodenalis. M.L. BAZÁN-TEJEDA*, R. ARGÜELLO-GARCÍA, R.M.
BERMÚDEZ-CRUZ, Departamento de Genética y Biología Molecular, Centro de Investigación y de
Estudios Avanzados-IPN, México DF, M. ROBLES-FLORES, Departamento de Bioquímica, Facultad de
Medicina, UNAM, México DF, and G.M. ORTEGA-PIERRES, Departamento de Genética y Biología
Molecular, Centro de Investigación y de Estudios Avanzados-IPN, México DF, México.
99
ABSTRACTS
PKC isoforms are members of a serine/threonine kinases family that are involved in regulation of several
cellular processes. Recently, we demonstrated that Giardia duodenalis expresses several PKC isoforms.
However, only one conventional PKC β-like was detected. In this study, we characterized the gPKC β
expression and subcellular localization during G. duodenalis encystment. We also determined the catalytic
activity of gPKC β. This kinase has a MW of 150 kDa and showed an increase expression during the
inductive phase of encystment. IIF assays showed that, in trophozoites, gPKC β was localized in the
cytoplasm. By 10 minutes post-encystment induction, it was detected in the membrane. In vitro phosphorylation assays showed that gPKC β displays kinase catalytic activity that depends on classic conventional PKC cofactors. In the Giardia genome database, we identified an ORF with homology to catalytic
domain of PKC2B from C. elegans and PKC1 from S. cerevisiae. This belongs to ORF 88644 that
encodes for a 46.6 kDa protein. This ORF was cloned and the recombinant protein was recognized by
polyclonal antibodies against the mammal PKC β II isoform. Upstream to ORF 86444, ORF 13775 is
located. This ORF contains sequences homologus to the C1 and C2 domains of calcium-dependent
PKCs. We hypothesized that this ORF encodes for the regulatory domain of gPKC β. The ORF 137754
encodes for a 107.8 kDa protein, while both ORFs encode for a hypotethical protein of 154 kDa.
However, these ORFs are separated by 90 bp with two translation end codons TAA. It has been reported
the presence of alternative codon usage in Giardia that exhibit a slight bias to UGA, which would allow
readthrough of TAA codons. We amplified by RT-PCR two sequences of 536 bp and 1994 bp upstream
of the ORF 86444 using two primers: the gPKC3-F 8 (for the 536 bp) and the gPKC4-F (for the 1994
bp), located upstream in the ORF 137754, and the primer gPKC3-R, located at the 5´ end of ORF
86444. The results suggest that both ORFs encode for gPKC β mRNA.
103
Purification of α-Mannosidases from Entamoeba histolytica. C.E. SANTACRUZ-TINOCO*, E. LÓPEZROMERO and J.C. VILLAGOMEZ-CASTRO, Instituto de Investigacion en Biologia Experimental,
Facultad de Quimica, Universidad de Guanajuato, Guanajuato, Guanajuato, México.
The Entamoeba histolytica parasite represents a serious public health problem in the least developed
countries, ranking third in mortality due to protozoans, and causing nearly 70,000 annual deaths worldwide. In the first events of the pathogenic process from this parasite, specific surface glycoproteins
(adhesins) are very important; however, little is known on the mechanisms of biosynthesis, maturation
and secretion of these macromolecules in E. histolytica. Previous results from this laboratory have demonstrated that about 45% of α-mannosidase activity in this organism is associated with internal membranes
and that it may be involved in N-glycan processing. Here, we describe a purification protocol of a
membranal and soluble α-mannosidases from E. histolytica. Trophozoites were incubated up to the
exponential phase of growth in TYI-S-33 medium, harvested and washed twice with PBS. Later, they
were ballistically disrupted, resuspended in 20 mM Hepes, buffer pH 7.2 containing 2 mM E64 and
centrifuged al 100,000 x g for 1 h. The supernatant was subjected to anionic exchange chromatography
in a HR 5/5 Mono Q column and eluted with a 0.–0.3 M lineal gradient of NaCl in the same buffer, 1
ml fractions were colleted. Most active fractions were pooled and subjected to preparative native PAGE
in 6% gels. The enzyme were visualize and bands were cut off and eluted overnight at 4°C with buffer.
The membranal enzyme was first solubilized with Tx-114 and subjected to same protocol. Only 30 and 6
folds were purified soluble and membranal enzymes, respectively. SDS-PAGE showed two bands of
protein for soluble enzyme and six for membranal activity. Now we are recovering more pure protein to
biochemical characterization of both enzymes. (Work supported by Grant C-02-39529-Q from SEPCONACyt, México.)
104
Comparison of Membrane Lectins Between Naegleria fowleri and Naegleria gruberi. A. SILVAOLIVARES*, I. CERVANTES-SANDOVAL, Department of Experimental Pathology, CINVESTAV-IPN, J.
PACHECO-YEPEZ, Electron Microscopy Laboratory, Mexican Faculty of Medicine, La Salle University,
México DF, V. TSUTSUMI, Department of Experimental Pathology, CINVESTAV-IPN, and M.
SHIBAYAMA, Department of Experimental Pathology, CINVESTAV-IPN, México.
Naegleria fowleri is a free-living ameboflagellate and the etiologic agent of the primary amoebic meningoencephalitis (PAM), an acute and rapidly fatal central nervous system (CNS) disease. Adhesion of
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amoebae to the host cells is an important step in the invasion process; therefore, surface molecules such
as glycoproteins must have an important role during this event. The aim of this study was to determine
the differences in the glycoprotein composition between the pathogenic N. fowleri and the non-pathogenic N.gruberi strains using lectins with different carbohydrates specificity. We analyzed by flow cytometry, the expression of surface glycoproteins in axenic trophozoites. Cells of both amoebic strains were
fixed and then incubated with the following biotinilated lectins: Canavalia ensiformis (Con A) that
recognize glucose, Tetragonolobus purpurea (lotus agglutinin) that has an affinity for fucose residues, Helix
pomatia (HPA agglutinin) that identify specific galactose and Pisum sativum (PSA agglutinin) and
Galanthus nivalis (GNL lectin) that both recognize manose residues. After washing, amoebae were
incubated with streptavidin–fluorescein and analyzed by Fluorescent Activation Cell Sorting (FACS).
Results showed that the pathogenic strain N. fowleri expressed with stronger intensity (2.7 fold higher)
the glycoproteins recognized by both, Con A and lotus agglutinin, in comparison with N. gruberi. No
differences were found with the other lectins. To identify glycoproteins recognized by these two lectins,
extracts of both strains were electrophoresed, transferred to nitrocellulose membranes and then incubated
with the biotinilated lectins. Con A recognized several glycoproteins from 15 to 150 kDa in both strains,
but with higher intensity in N. fowleri as compared with N. gruberi. Lotus agglutinin recognized a single
protein of 80 kDa in both strains, although the band intensity was stronger in N. fowleri. These results
suggest that carbohydrates residues of glucose and fucose may be involved in cell adhesion, and consequently in the invasion process to the host cell.
105
Effect of Cholesterol on the Virulence of Entamoeba histolytica. J.M. GUTIÉRREZ-MEZA*, Department
of Experimental Pathology, CINVESTAV-IPN. México DF, R. MEJIA-ZEPEDA, UBIMED FES-Iztacala,
UNAM, México DF, V. TSUTSUMI, M. SHIBAYAMA, Department of Experimental Pathology,
CINVESTAV-IPN, México DF, and J.J. SERRANO-LUNA, Department of Cell Biology, CINVESTAV-IPN,
México DF, México.
Polyxenic and axenic strains of Entamoeba histolytica lose their virulence after prolonged in vitro culture. It
is known, however, that trophozoites can maintain their virulence by adding cholesterol in the culture
medium. To understand better this phenomenon, we analyzed the effect of cholesterol lyposomes on
E.histolytica trophozoites. Amoebae of different virulence and culture conditions were tested: (a) Wild
type HM1-IMSS strain (W) grown in a normal Diamond medium; (b) the same W strain, but grown in
a cholesterol lyposomes-enriched medium (WC), (c) Virulent HM1-IMSS strain (V) (previously passed
through hamster liver), cultured in a normal Diamond medium; and (d) the same V strain, but cultured
in a cholesterol-enriched medium (VC). In vivo virulence of each strain of E. histolytica was evaluated in
the hamster model by intrahepatic inoculation of 1 x 106 trophozoites. Animals were sacrificed at the 7th
day post-inoculation and the percentage of liver abscess was determined. For erytrophagocytic assay,
trophozoites interacted with human erythrocytes at a 1:100 ratio (amoeba:erythrocytes) for 5 and 15
min. Absorbance of each sample was measured in a spectrophotometer at 405 nm. Endocytic activity
was determined by using inert particules. Amoebae interacted with fluorescent microspheres (1µm) at a
1:100 ratio, for 5 and 15 minutes, and measured by flow cytometry. Strains V and VC were able to
produce large amoebic liver abscess (43.5 and 43.7%, respectively). At 15 min, these strains also had a
higher erytrophagocytic rate than in strain W. In comparison with W strain, strain VC showed more
endocytic microspheres at 5 min. This endocytic activity diminished at 15 min of interaction. Contrarily,
no difference in endocytic capacity was detected between V and VC strains. In conclusion, cholesterol
lyposomes added to the culture medium appears to maintain the virulence in E. hitolytica trophozoites
without requiring the previous passage through a hamster liver. Molecular and biochemical mechanisms
involved in the virulence activation, however, remain to be determined.
106
Virulence Behavior of a Brazilian Isolate of Entamoeba dispar. S. SANTANA-DOLABELLA*, Department
of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Brasil, J.J.
SERRANO-LUNA, F. NAVARRO-GARCIA, Department of Cell Biology, CINVESTAV-IPN, México DF, V.
TSUTSUMI, Department of Experimental Pathology, CINVESTAV-IPN, México DF, and M. SHIBAYAMA,
Department of Experimental Pathology, CINVESTAV-IPN, México DF, México.
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ABSTRACTS
Entamoeba dispar is a species responsible for most of the cases of non-invasive amoebiasis, considered
non-pathogenic. Other studies have shown that the amoeba does not secrete significant quantities of
proteases, thus it is incapable of producing damage in the host. There is some evidence, however, of
temporal and small lesions in hamster liver and intestine produced by E. dispar. In the present work, we
analyzed the profile of proteases of E. dispar (ADO) strain isolated in 1997 from an asymtomatic patient
in Brazil. The ADO strain was maintained in a polyxenic culture with the host’s original flora, containing
Escherichia coli and Shigella sp. This strain presents a non-pathogen isoenzimatic profile type I, according
with Sargeaunt. The virulence was tested in the hamster liver and in MDCK cells. The ADO strain
showed extensive damage in the hepatic parenchyma, as well as the destruction of MDCK monolayer
cells. Proteolytic assays of total extracts (20 µg) and conditioned medium (20 µl) have been carried out
in copolymerized porcine gelatin gels. Two main bands of 97KDa and 55KDa in the total extracts were
detected. Meanwhile, a 97KDa was present in the conditioned medium. To quantify the proteolytic
activity of the E. dispar strain, a colorimetric assay with azure hide powder and azocoll substrates was
carried out with total extracts (100 µg) and conditioned medium (100 µl). A stronger proteolytic
activity was present in both, total crude extracts and in conditioned medium of ADO strain in comparison with E. histolytica HM1:IMSS strain. On the other hand, the proteolytic activity was abolished in
total extracts as well as in conditioned medium with cysteine protease inhibitor, para-hydroxymercuribenzoic acid (PHMB). These results showed the pathogenic behavior of this isolate, contrary to
reports of the axenic culture of E. dispar (SAW-760). More studies are need to elucidate the pathogenic
mechanisms involved in the virulence of this Brazilian isolate of E. dispar.
107
EhABP152, a New Actin Binding Protein from Entamoeba histolytica. A.D. CAMPOS-PARRA*, M.D.
ALMARAZ-BARRERA and M.Á. VARGAS-MEJIA, CINVESTAV-IPN, Depto. of Molecular Biomedicine,
México DF, México.
Microfilaments, microtubules and intermediate filaments comprise the cytoskeleton that maintains the
intracellular architecture. In the parasite pathogen Entamoeba histolytica, the actin cytoskeleton has a great
importance in different cellular processes related to the invasion of different cell targets. Nevertheless, the
mechanisms and proteins related to the movement of E. histolytica are poorly defined. It is known,
however, that the actin and the actin binding proteins (ABPs) in high eukaryotic cells can form highly
ordered structures that provide shape and support to the cells. Due to the importance of ABPs during the
reorganization of the cytoskeleton and in the mechanism of the pathogenicity from E. histolytica, in this
project we focused on a new ABP protein from E. histolytica denominated EhABP152. The EhABP152
has a MW of 152 kDa, and a pI 5.22. This protein has a 23% of identity and 50% of homology with the
α-actinin from Aspergillus fumigatus. It has a conserved putative ABD domain (Gln20–Phe234), a
putative binding to microtubules (MAP) region (Lys705–Lys1021), and at the C-terminal region a DUF
domain of unknown function. By RT-PCR assays, it was determined that the gene EhABP152 is transcribed in the amoeba. By fluorescence microscopy of PExEhNeo/HSV-tagged-EhABP152 transfected
cells, it was observed that the EhABP152 protein is located in the plasmatic membrane as well as in the
nucleus of E. histolytica.
108
Subcellular Organization of 11 Actin-like and Actin Related Proteins (ARPS) from Entamoeba histolytica. E. GUZMÁN-HUERTA* and M.Á. VARGAS-MEJIA, Departamento de Biomedicina Molecular,
CINVESTAV, México DF, México.
Conventional actin is one of the principal components of the eukaryotic cytoskeleton, and it has a
principal role in cellular processes from the cell motility to cell organization. It is also well known that
actin, together with actin related proteins (ARPs), participates in activities inside the nucleus such as
regulation transcriptional, export nucleocytoplasmic of the mRNA and as a component of the nucleoskeleton. In the protozoan parasite Entamoeba histolytica, the actin cytoskeleton is very important for the
mechanisms of pathogenicity of this parasite. It is unknown, however, if in E. histolytica’s cytoskeleton
there are actin’s isoforms as in higher eukaryotes, if there are ARPs, and if these together with actin could
be participating in the transcriptional regulation of this parasite. In this study, we identified 11 new
genes of E. histolytica actin-like and ARP, which, through bioinfomatic analysis, we determined have an
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actin domain. By fluorescence microscopy of pExEhNeo/HSV-tagged-Eh (actin, actin-like, ARP)
transfected cells, it was observed that these proteins are located in the plasmatic membrane, cytoplasm
and nucleus of E. histolytica. By RT-PCR assay, it was determined that the 11 genes of E. histolytica are
transcribed in the parasite.
109
Atlas of the Developmental Stages of Taenia solium. F. MENDLOVIC*, Departamento de Microbiología
y Parasitología, Facultad de Medicina, UNAM, México DF, J. CARILLO-FARGA, J. TORRES, Instituto de
Hematopatología, Cuajimalpa, and A. FLISSER, Departamento de Microbiología y Parasitología,
Facultad de Medicina, UNAM, México DF, México.
We have elaborated an atlas of the different life stages of Taenia solium. Three different stains were used:
Giemsa, Masson’s trichromic, and periodic-acid Schiff (PAS). Two µm tissue sections were obtained from
invaginated and evaginated cysticerci, as well as from proglottids at different stages of maturation,
including gravid proglottids. In the evaginated scolex stained with Giemsa, evident differences in the
tegument and number of tegumentary cytons are clearly apparent when compared with the apical region
and neck, where stem cells have been reported. At the region where the neck and vesicular membrane
join, a large number of calcareous corpuscles can be observed. The Masson stain revealed a different
composition of the parasite’s tegument at this interface. A layer of collagen fibers between the tegument
and tegumentary cytons is present at the neck portion that is lacking in the vesicular membrane. Interestingly, the rostellum, which is armed with a double crown of hooks, shows very similar cytology to that of
the suckers, suggesting a common origin of these structures. In sections stained with PAS, which detects
glycogen, a high abundance in the musculature of suckers and rostellum was evident, as well as in the
tegumentary cytons and tegument. The tegument at the apical portion of the scolex is also highly
positive to PAS stain. In developing proglottids of 36-day tapeworms, carbohydrates are not detected at
the genital anlagen. A similar staining pattern was observed in mature proglottids, where the differentiated sexual organs are PAS negative. Finally, oncospheres show a surrounding PAS positive membrane
closely associated with the oncospheral cells. This atlas is an important contribution, since little information on the histology of the life cycle of Taenia solium is available in the literature.
110
Actin Localization in Different Stages of Trypanosoma cruzi. Y.X. SEGURA-KATO*, Departamento de
Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM, México DF, H.
MERCHANT-LARIOS, Departamento de Biología Celular y Fisiología, UNAM, México DF, R.G. MANNING-CELA, Departamento de Biomedicina Molecular, CINVESTAV, México DF, I. LÓPEZVILLASEÑOR, R. HERNÁNDEZ and A.M. CEVALLOS, Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
Trypanosoma cruzi (T. cruzi) is the aetiological agent of Chagas disease. T. cruzi cytoskeleton is peculiar
because it is formed basically by tubulin. Although we know actin is expressed (43kDa) in T. cruzi, there
is no clear evidence about actin or microfilaments localization and function. In this study, we determined
actin localization in the different stages of T. cruzi (epimastigotes, trypomastigotes and amastigotes) by
confocal microscopy immunolocalization using a polyclonal rabbit serum against a GST-T. cruzi actin
recombinant protein. In the three stages, the protein is expressed and it was distributed in a diffuse way
throughout the cell. We observed, however, concentrations in replicative stages. In epimastigotes, actin
was concentrated mainly in specific sites: in the posterior region of kinetoplast (endocytosis site) and in
several spots along the flagella. While in amastigotes population, actin concentrations with heterogeneous signal levels and localizations were observed. In conclusion, our results indicate a different actin
localization throughout the T. cruzi life cycle. Also, they suggest an actin role for epimastigotes in
endocytosis and possibly in adhesion through its flagella, an important process for the transformation to
trypomastigotes. Finally, they suggest a high actin dynamic in amastigotes whose importance have to be
determined.
111
AP3 Complex and Leishmania Remodeling. C. RHODES, F. SHAW, JR. and J. PORTER-KELLEY*,
Department of Life Sciences, Winston–Salem State University, Winston–Salem, NC, USA.
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Leishmaniasis is a human and animal disease caused by the protozoan parasite Leishmania. It is a major
affliction in the tropical and oubtropical parts of the world, including areas U.S. soldiers currently
occupy. One longstanding question in Leishmania biology is how the parasite transitions from one
developmental form to the other. Recent studies have shown that this developmental transition occurs by
protein and lipid synthesis and degradation, also known as cellular remodeling. Protein and lipid synthesis has been well characterized in eukaryotes; however, there is not much known about protein and lipid
degradation. Trafficking to the lysosomes appears to be involved in the degradation process whereby
proteins and lipids are degraded by transport to lysosomes. We are interested in unraveling the pathway
by which these proteins and lipids are transported to the lysosomes for degradation. Based on our
literature searches, the AP3 complex may play an important role in the transport process. Here we show
the initial molecular characterization studies of the four components that make up the AP3 complex in L.
major promastigotes.
112
Actin Cytoskeleton in Acanthamoeba castellanii Evidenced by Means of Rhodamine–Phalloidin Complex and Cryo-electronmicroscopy Techniques. A. GONZÁLEZ-ROBLES*, G. CASTAÑON-GUTIÉRREZ,
Departamento de Patología Experimental, Centro de Investigación y de Estudios Avanzados del IPN,
México DF, and A. MARTÍNEZ-PALOMO, Departamento de Patología Experimental, Centro de Investigación y de Estudios Avanzados del IPN, México DF, México.
Acanthamoebae are ubiquitous free-living amoebae. Acanthamoeba castellanii is recognized as the etiological agent of amoebic keratitis, a progressively painful, sight-threatening infection of the eyes occurring in immunocompetent persons. The mechanisms involved during the invasion of the amoeba in the
cornea are poorly understood. It has been recognized that the initial step of corneal infection involves the
adhesion of trophozoites to the corneal epithelium. It is accepted that actin cytoskeleton plays a structural and dynamic role in diverse functions of the cell such as adhesion, motility, phagocytosis and other
processes. During locomotion, coordinated actin assembly near the plasma membrane creates lamelipodia and filopodia. These structures, along with the movements of the amoebae, play an important
function in the first steps of the cytophatic effect. By means of light and electron microscopy, we described different structures formed by actin in Acanthamoeba castellanii. Trophozoites were cultured at
30ºC and harvested after three days during the logarithmic phase of growth by chilling the culture tubes
in an ice-water bath for 15 min. After centrifugation at 2,000 rpm for 5 min, the pellets were resuspended in a culture medium. Polimerized actin was visualized by fluorescence microscopy and cryoelectron microscopy techniques. For fluorescence microscopy, trophozoites were fixed with 4% paraformaldehide, permeabilized with 0.2% Triton-X and treated with 1:25 rhodamine-tagged phalloidin
complex. Cryo-fixation and cryo-substitution were used for visualization of actin filaments, along with
cryo-sections where actin was detected by means of a monoclonal anti-actin antibody followed by a
secondary antibody conjugated to gold particles. Actin cytoskeletons were clearly detected in the acanthopodia, adhesion plates and in endocytic structures.
113
Preliminary Filamentous Protein Studies in Different Compartments from Cysticerci of Taenia solium.
O.A. REYNOSO-DUCOING*, X.M. GONZÁLEZ-GUERRERO, Y. ROMERO-ACEFF and J.R.
AMBROSIO-HERNÁNDEZ, Facultad de Medicina, UNAM.
The cellular cytoskeleton is constituted by actin filaments, microtubules, intermediate filaments and their
associated proteins assemble into network of proteins filaments that organized the contents of the
cytoplasm. The cytoskeleton also plays the preeminent role in determinate the shape and polarity of the
cell and the nature of its movements, like muscle contraction in Taenia solium is produced by the sliding
of actin filament against myosin II and the transport role for microtubules is the traffic of vesicles inside
the cell body. Our group has been studying the expression of cytoskeleton proteins in taeniids parasites
and we had found the existence of several isoforms in these parasites, which are probably associated to
physiological requirements of each developmental stage, thus they may have important roles in determining the direction and strength of movements required by the parasites in response to various physiological situations. In preliminary studies, we had obtained biochemical information, using SDS-PAGE and
Western Blot strategies that indicates that contractile proteins like actin, myosin II and tubulin are in all
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cysticercus compartments: tissues and vesicular fluid and the level of protein expression and quality is
different in each section. Some interesting questions then emerge: Are these contractile proteins fully
functional in all compartments? Have these proteins differents isoforms that express in each structure
that integrate it? Why are these proteins in vesicular fluid? (Work supported by Conacyt-México 46629
and DGAPA-UNAM IN201003 and IN216107.)
114
Diplostomiasis in Fish from Tres Palos Lagoon, Guerrero, México. J. VIOLANTE-GONZÁLEZ* and A.
ROJAS-HERRERA, Unidad Académica de Ecología Marina (UAG), Acapulco Guerrero, México.
An analysis was done to determine the distribution of diplostomiasis (eye fluke) in fish in Tres Palos
Lagoon, Guerrero, México. A total of 1,240 fish from 10 species were examined between April 2000 and
February 2003. Diplostomiasis diagnosis was done by necropsy with microdissection of eyes. The
helminth parasite causal agent was identified as Austrodiplostomum compactum metacercariae. Degree of
infection varied by host species. The prevalence of infection was as high as 20% in Cichlasoma trimaculatum, Astianax fasciatus and Poecilia sphenops, and less than 1% in Gobiomorus maculatus and Eleotris
pictus. The mean infection intensity was more than three helminths per infected host in Ariopsis guatemalensis and Centropomus robalito, while four host species had only a single parasite. The maximum number
of A. compactum metacercariae taken from a single host was 28, although 50% of hosts had only one to
two parasites. Mean host size did not correlate with prevalence or mean intensity parameters. Differences
in infection levels were attributed to host habitat. Host species with higher infection percentages, such as
C. trimaculatum, A. fasciatus or P. sphenops, tend to inhabit shallow areas near lagoon margins, placing
them in contact with the mollusks (snails) that act as first intermediary hosts for A. compactum. Mature
A. compactum have been identified in the duck Phalacrocorax olivaceus, a resident piscivorous bird.
Diplostomiasis in Tres Palos Lagoon does not cause mortality in fish populations. Its presence in the
lagoon is important to consider, however, if fish from Tres Palos Lagoon are be to used in aquaculture
applications or to repopulate other bodies of water.
115
Fish Predation on Trematode Cercariae in a California Estuary. A.T. KAPLAN*, S.E. HALLING, K.D.
LAFFERTY and A.M. KURIS, Ecology, Evolution and Marine Biology Department, University of California, Santa Barbara CA, USA.
In salt marsh ecosystems where the snail Cerithidea californica is infected with digenean trematodes,
trillions of cercariae are shed into the estuary every day, but a large percentage of cercariae do not reach
their second intermediate hosts. Cercarial mortality factors are little studied and the role of predators as a
mortality source is unknown. Our laboratory studies indicate that several zooplanktivorous fishes are
potential predators. Seven local estuarine fish species were brought into the lab and offered cercariae
from 12 trematode species that reside with them in the marsh. Thirty minutes after the fish were presented with cercariae, they were examined for the presence of cercariae in the gut. Most of these fishes
rapidly engorged on cercariae. We also examined the relationship between the size of these fishes and
cercarial feeding behavior; juvenile fish of some species were much more likely to consume cercariae. The
species of fishes that preyed on cercariae in the lab were then examined in the field. We collected juvenile
fishes form very shallow water on the rising tide, as cercariae are released from snails under these conditions. These fishes were dissected immediately (in the field) and their gut contents were examined. of 75
fish dissected, we found cercariae in the foregut of three of those fish. We believe these juvenile fishes are
a significant source of mortality for trematode cercariae in the salt marshes along the coast of California.
116
Influence of Freshwater Inflows on Shellfish Responses in Southwestern Florida Estuaries: Utilizing
Shellfish Responses in Ecosystem Management and Restoration. A.K. VOLETY*, G. TOLLEY, L.
HAYNES, A. BRIDGES, Florida Gulf Coast University, Fort Myers FL, D.J. CREAN and P.H. DOERING,
South Florida Water Management District, West Palm Beach FL, USA.
Ecosystem restoration and management seek to repair or improve a suite of desired environmental
conditions for a specific ecosystem. Alterations in freshwater inflow, resulting from watershed development and water management practices, have impacted salinity and water quality within southwestern
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Florida estuaries. For example, in the Caloosahatchee estuary, where oyster abundances have declined
precipitously from historic values, altered hydrology including unnatural high and low water deliveries to
the estuary have been identified as key stressors. To investigate the effects of seasonal changes and
watershed management on oysters, relationship between freshwater inflows, salinities and oyster responses were investigated from three estuaries (Caloosahatchee River, Estero River and Henderson
Creek) in southwestern Florida. A significant relationship exists between freshwater inflows and salinities
in the estuaries (R2 65–84%). Prevalence and intensity of Perkinsus marinus infection varied over the
sampling period and decreased with an increase in freshwater inflows. Depending on the estuary, inflows
between 50 and 3,000 cubic feet per second would result in optimal salinities that would support and
enhance oyster reefs in southwestern Florida estuaries. The condition index of oysters varied with the
reproductive activity of oysters. Oysters in southwestern Florida estuaries continuously spawn between
May–October, a period that coincides with rainfall and freshwater discharges through water management
structures. Results further suggest that well-timed freshwater releases into the estuaries may lower P.
marinus infections to non-lethal levels in oysters, thereby increasing survival. Freshwater inflows should
be minimized during the spawning months to facilitate the spat recruitment of oysters onto oyster reefs.
Limited freshwater releases during winter coupled with decreased releases in summer should result in
suitable conditions for survival and enhancement of oyster reefs in the estuaries. These results suggest
that the responses of oysters can be a useful tool for managing southwestern Florida estuaries.
117
Bioindicators of Chemical Pollution in Tropical Coastal Lagoons: An Integrative Approach Using Fish
Biomarkers and Helminth Parasites. D. PECH* and V.M. VIDAL-MARTÍNEZ, Departamento de
Recursos del Mar, CINVESTAV, Mérida, Yucatán, México.
The suitability of using fish biomarkers and helminth communities as bioindicators of environmental
quality of the Yucatán coastal lagoons status was tested on the checkered puffer (Spheroides testudineus). A
multidisciplinary approach was undertaken to measure the concentration of organic and inorganic
sediment pollutants, water hydrology parameters and the relative abundance of helminth parasite infracommunities, as well as the fish physiological responses to pollution, using biomarkers. Sediment analysis
revealed the presence of hydrocarbons, organic pesticides and polychlorinated biphenyls with different
degrees of concentration in each of the lagoons. Results from fish biomarkers showed a high catalase
activity and a low fish condition index related to the presence of chemical pollutants. Moreover, significant negative associations among organoclhorine pesticides (DDTs and TCBs), infracommunity characteristic and fish physiological response were observed. The general findings suggest that these chemical
pollutants seem to be causing a negative effect on abundance, richness and diversity in helminth infracommunity patterns despite the degree of pollution of the lagoon. Overall, this finding suggests that
helminth parasites seem to be promising bioindicators of the environmental status of coastal lagoons.
Additionally, fish physiological response, such as catalase activity and condition index, appear to be useful
tools for early detection of potential effects of chemical pollutants on the fish host.
118
Spatial Distribution and Coexistence of Dactilogyridae (Monogenea) Inhabiting Wild Spotted Rose
Snapper’s Gills (Lutjanus guttatus) from the Mazatlán Bay in México: Preliminary Studies. L.C. SOLER
JIMENÉZ*, Centro de Investigación en Alimentación y Desarrol, and E.J. FAJER-ÁVILA, Centro de
Investigación en Alimentación y Desarrollo A.C, Unidad Mazatlan en Acuicultura y Manejo Ambiental,
Sinaloa, México.
First attempts at culturing spotted rose snapper, Lutjanus guttatus, have shown recurrent dactylogyrids
monogenean infestation, causing hyperplasia of gill lamellae and anorexia. Ecological studies have been
started in order to develop effective management strategies. The spatial distribution and coexistence of
different dactylogyrids species from a wild spotted rose snapper’s population in Mazatlán, México are
being investigated. The aim of this study is to define the microhabitat of each parasite species, describing
their location, prevalence and abundance on the gills. Gill arches are dissected, numbered and divided
into three equal regions: front, middle and back. Parasites are localized on each region by a dissecting
microscope and isolated alive from the gill filaments to be identified and counted under a compound
microscope. Two Euryhaliotrema and four Haliotrema species have been found. Preliminary results
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showed that Euryhaliotrema sp.1 and Haliotrema sp.2 had the highest prevalence (90 and 73%) and
similar mean abundance (28.12 and 28.7 parasite per fish), respectively, while the lowest prevalence was
found to Euryhaliotrema sp.2 (22 %). Haliotrema sp.2 was the dominant species with 1,177 individuals,
followed by Euryhaliotrema sp.1 with 1,153 individual from the total sampling time so far. The role of
interspecific and intraspecific relationships in the spatial distribution of monogeneans using the “aggregation model of co-existence,” as well as niche breadth and overlap niche of the parasites species, will be
done.
119
Helminth Fauna of the Grey Snapper, Lutjanus griseus, along the Southern Coast of Quintana Roo,
México. D. GONZÁLEZ-SOLÍS, Parasitología del Necton, El Colegio de la Frontera Sur, Unidad
Chetumal, Chetumal, Quintana Roo, México.
Along the Caribbean coast of México, several commercially important fishes are very common. In spite
of economic and social importance of these aquatic vertebrates in the region, surveys dealing with the
parasites affecting wild fish populations and their community structure are scarce. Therefore, the main
goal of this investigation was to determine and characterize the helminth community structure of one of
the most valuable fish species, the grey snapper (Lutjanus griseus) along the southern coast of Quintana
Roo. A total of 360 specimens were collected from June 2004 to May 2005 in 13 localities mainly
located within the Chetumal Bay and southern coast of Quintana Roo. All fishes examined were infected
by at least one helminth species. The results showed that the richness of the helminth community of the
gray snapper was very high, with a total of 53 species found (six monogeneans, 20 trematodes, two
cestodes, 18 nematodes and seven acanthocephalans). This is the richest helminth community so far
described from marine fishes in México. At the infracommunity level, the highest number of species was
14. Haliotrema gracilihamus (70.3%) and Metadena adglobosa (66.9%) were the most prevalent helminths, the latter being also the most abundant species (100.38). Trematodes were the parasitic group
with the highest number of species recovered during this survey, followed by nematodes and acanthocephalans. Most helminths were adult forms (32 species), autogenic (38) and specialists (23), although
larval stages (21), allogenic (12) and generalist (28) species, also were present.
120
Expressed Sequence Tags (ESTS) Generated from Cysts and Trophozoites of Giardia duodenalis Belonging to Assemblage A, Using Subtractive Hybridization. K.B. MISKA*, J.M. TROUT, APDL, ARS, USDA,
Beltsville MD, and G.H. ROSENBERG, Department of Biology, The University of New Mexico, Albuquerque NM, USA.
To characterize genes expressed by assemblage A of Giarida duodenalis, sequences of 1,391 ESTs were
obtained from cDNAs enriched for transcripts expressed by the trophozoite and cysts stages. To obtain
these libraries, cDNA from G. duodenalis cysts was subtracted via hybridization with cDNA from trophozoites. A reverse subtraction also was carried out, in which cDNA from trophozoites was subtracted with
cDNA from cysts. This procedure enriches the presence of transcripts specific to these two stages. When
EST sequences were assembled, 924 unique contiguous (contigs) sequences were identified. Two hundred and twenty two contigs were composed of more than one overlapping sequence. When compared
to the nr database using Blastx, it was found that all sequences encode proteins hypothetically encoded in
the Giardia genome. Additionally, blastn comparison against the Giardia genome confirmed that all
sequences obtained in this study are derived from Giardia.
121
The Unique Fatty Acid Synthetic Capability of the Oyster Parasite, Perkinsus marinus: Implication for
Chemotherapeutic Treatment. F.E. CHU*, E.D. LUND and J.A. PODBESEK, Department of Environmental and Aquatic Animal Health, Virginia Institute of Marine Science, College of William and Mary,
Williamsburg VA, USA.
The protozoan, Perkinsus marinus, is presently the most prevalent parasite of the eastern oyster Crassostrea
virginica in mid-Atlantic water of the U.S. Similar to Plasmodium sp, this parasite is capable to synthesize
phospholipids and, as most other parasitic protozoans, can acquire and metabolize exogenous lipids.
However, unlike other parasitic protozoans, P. marinus is able to synthesize a range of saturated and
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unsaturated fatty acids, including the essential fatty acid, arachidonic acid. To determine whether the
antibiotic, triclosan, is a useful chemotherapeutic agent to target the parasite fatty acid synthesis, we
tested its effects on the parasite and its host. While causing minimal effect on oyster hemocyte viability,
we found that triclosan not only inhibits growth and greatly reduces the viability of P. marinus meronts,
the primary disease transmission stage, but also inhibits the fatty acid synthetic ability of the parasite.
Due to the importance of temperature on disease progression in the field, we also tested the effects of
triclosan on the viability of P. marinus meronts and oyster hemocytes at various temperatures. Parasite or
oyster hemocytes were exposed to triclosan (0, 2, 5, or 10 µM) for 24 hr at different temperatures and
their viabilities were assessed by MTS/PMS assay. Exposure of P. marinus meronts to 2, 5, or 10 µM
triclosan at 20, 26 and 28°C significantly reduced their viabilities (40–60%). Meronts had a better
triclosan tolerance at 13°C. Oyster hemocytes treated with triclosan exhibited less than 10% mortality at
≤ 10 µM triclosan at 13°C and viabilities reduced slightly (10–16%) at 5 and 10 µM triclosan exposure
at 20°C. No significant reduction in viability occurred in hemocytes at 2 to 10 µM triclosan at 26°C.
Triclosan slightly affected the reactive oxidative intermediate (ROI) production measured by chemiluminescence assay. A dose-dependent response of ROI production was noted when hemocytes were exposed
to 0, 2, 5, or 10 µM triclosan at 20°C. (This study is supported by ODRP, NOAA [Grant V710720].)
122
A Monoadp-ribosyl Transferase Activity Modify a Secreted Glyceraldehyde-3-phosphate Dehydrogenase in Entamoeba histolytica Extracellular Medium. A.H. ALVAREZ, CIATEJ, Guadalajara, Jalisco, G.
MARTÍNEZ-CADENA, M.E. SILVA, Instituto de Investigacion en Biologia Experimental, Facultad de
Quimica, Universidad de Guanajuato, Guanajuato, E. SAAVEDRA-LIRA, Departamento de Bioquimica,
Instituto Nacional de Cardiologia, México DF, and E.E. AVILA*, Instituto de Investigacion en Biologia
Experimental, Facultad de Quimica, Universidad de Guanajuato, Guanajuato, México.
Due to the important role of monoADP-ribosyl transferases in physiological events and as the mechanism of action of several bacterial toxins, we investigated whether the protozoan parasite Entamoeba
histolytica has monoADP-ribosyl transferase activity. Reactions were performed using ameba-free medium
as the source of both enzyme and ADP-ribosylation substrate(s) and [32P]NAD+ as source of ADPribose. Proteins were analyzed by electrophoresis, and [32P]-labeled proteins were detected by autoradiography. A major labeled product of 37,000 Da was observed in the extracellular ameba-free medium.
The 37-kDa substrate was enzymatically ADP-ribosylated because the reaction depended on time,
temperature, pH, and the appropriate controls excluded the unspecific binding of NAD or ADP-ribose.
The 37,000 Da ADP-ribosylated protein was identified by MaldiTof as glyceraldehyde-3-phosphate
dehydrogenase. We observed that glyceraldehyde-3-phosphate dehydrogenase is secreted from ameba in a
time- and temperature-dependent manner and its enzymatic activity was not inhibited by ADP-ribosylation. On the basis of sensitivity to NH2OH of ADP-ribose bound to the 37,00 Da protein, it was
determined that the extracellular glyceraldehyde-3-phosphate dehydrogenase was ADP-ribosylated in an
arginine residue. These results demonstrate the existence in E. histolytica of a monoADP-ribosyl transferase that modify a glyceraldehyde-3-phosphate dehydrogenase, whose localization depends upon a
secretion process. In other organisms, glyceraldehyde-3-phosphate dehydrogenase has been implicated in
many activities such as membrane fusion, binding to host proteins and signal transduction, in addition to
its classic glycolytic role. Extracellular glyceraldehyde-3-phosphate dehydrogenase from ameba may play
an important role in the survival of this important human pathogen or in interaction with host molecules, as occurs in other organisms.
123
Analysis of Cytoadherence and Cysteine Protease Activity in Fresh and Long-term Grown Isolates of
Trichomonas vaginalis and their Relationship with Virulence. B.A. ALVAREZ-SANDOVAL*, A. RANGELSERRANO, L. CARACHEO-DELGADO, F. ANAYA-VELÁZQUEZ, F. PADILLA-VACA, Instituto de Investigación en Biología Experimental, and J.F. ALDERETE, Departament of Microbiology, University of Texas
Health Science Center, San Antonio TX, USA.
Trichomonas vaginalis is a protozoan parasite that causes the most common sexually transmitted disease of
nonviral origin in humans, which infects the urogenital tracts of more than 200 million people worldwide. Trichomoniasis is associated clinically with preterm delivery, low-birth-weight infants, infertility,
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pelvic inflammatory disease, chronic pelvic pain, and increases in human immunodeficiency virus transmission. The clinical spectrum varies from an asymptomatic to a severe symptomatic state. T. vaginalis
infects the epithelium of the genital tract and several studies seem to agree that parasite adhesion to
epithelium cells is the initial step leading to infection in women. Cytoadherence is crucial for T. vaginalis
to establish an infection, and it has been shown to involve multiple surface adhesion proteins and
lipophosphoglycans. The parasite’s cysteine proteinase activity is necessary for recognition and adhesion
of the parasite to the superficial epithelial cells of the host. However, the mechanism by which it infects
leading to the disease is not thoroughly understood. To address this issue, we determined the capability
of fresh and long term grown isolates of T. vaginalis to adherence and destroy to monolayers of MDCK
cells. The proteolytic activity also was evaluated in those isolates. Our data show that the long-term
grown isolates (GT-21 and 9910E) have the highest cytopathic activity, cytoadherence and cysteine
protease activity as high as the fresh isolate 9910F. Meanwhile, the low-virulent isolates, GT-7 and GT15, present the lowest cell adhesion and proteolytic activity. This research will help to identify additional
molecules involved in virulence and to decipher the pathogenic mechanism of T. vaginalis.
124
Entamoeba invadens: Inhibitors of Phosphatases and N-glycan Processing α-glycosidases Block Encystation. L.M. ALMANZA-VILLEGAS, Instituto de Investigación en Biología Experimenta, C.E. SANTACRUZTINOCO, E. LÓPEZ-ROMERO and J.C. VILLAGOMEZ-CASTRO*, Instituto de Investigación en Biología
Experimental, Facultad de Química, Universidad de Guanajuato, Guanajuato, Guanajuato, México.
Knowledge of encystation of Entamoeba histolytica is limited because no axenic encystation conditions are
presently available for this parasite. Studies have been carried out on in vitro axenic encystation of
Entamoeba invadens, a related reptilian parasite because of its close similarity with E. histolytica both in
morphology and development. During trophozoite differentiation into cysts, many events take place,
among which the expression of specific surface glycoproteins are very important. Little is known,
however, on the mechanisms of biosynthesis, maturation and secretion of these macromolecules during
encystations. Here, we analyzed the effect of 1-deoxinojirimicine and swansonine, which specifically
inhibit α-glucosidase and α-mannosidase, respectively, and ammonium vanadate and sodium pirophosphate, both in specific inhibitors of phosphatases, on differentiation of E. invadens in LG and LG47
media. Trophozoites were incubated up to the exponential phase of growth in TYI-S-33 medium,
washed with LG or LG47 media an inoculated in these media supplemented with 5% of serum in the
presence or absence of inhibitors. Encystment, cell viability by trypan blue exclusion and enzyme specific
activity were determined every 24 h in cyst whole homogenates. In both differentiation media, encystation of E. invadens was inhibited 80–90% by 42 µM 1-deoxinojirimicine and 6.7 mM sodium pirophosphate, 55–67% by 133 µM swansonine, and 5–10% by ammonium vanadate. Cell viability was lower
only in the LG47 medium with respect to the control without inhibitor. Specific activity of α-glucosidase
showed a major peak after 48 h and 96 h in LG47 and LG media, respectively, whereas α-mannosidase
activity was optimum after 96 h in both media. These results strongly suggest that some phosphatase and
glycoprotein processing α-glycosidases are involved in differentiation of E. invadens. (Work supported by
Grant C-02-39529-Q from SEP-CONACyT, México.)
125
Genetic Polymorphism in Taenia solium Cysticerci Recovered from Experimental Infections in Pigs. P.J.
MARAVILLA-CAMPILLO*, R. GONZÁLEZ-GUZMÁN, Departamento de Ecologia de Agentes Patogenos, Hospital General “Dr. Manuel Gea González,” México DF, G. ZÚÑIGA, Departamento de
Zoologia, Escuela Nacional de Ciencias Biologicas, IPN, México DF, A. PENICHE, J.L. DOMINGUEZALPIZAR, Departamento de Parasitologia, Facultad de Medicina Veterinaria y Zootecnia, UADY,
Mérida, Yucatán, R. REYES-MONTES and A. FLISSER, Departamento de Microbiologia y Parasitologia,
Facultad de Medicina, UNAM, México DF, México.
The information about the genetic structure of Taenia solium can be applied to the epidemiology and
transmission of cysticercosis, since genetic variants may differ in infectivity and pathogenicity. Until now,
however, the knowledge about this has been modest; T. solium cysticerci recovered from naturally
infected pigs from México, Honduras and Tanzania show a clonal structure and local lineages with
probable events of genetic recombination without genetic flow within them, as revealed by RAPD. To
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evaluate the genetic polymorphism from cysticerci recovered from experimental infections, four piglets
received T. solium eggs obtained from tapeworms released by three human carriers, a 10-year-old female,
a 25-year-old female, and a 44-year-old male; the fourth pig was infected with a mixture of eggs from the
three tapeworms. Each pig was orally inoculated with 50,000 eggs. After 16 weeks, the pigs were
humanely euthanized and cysticerci were excised. Parasites recovered from each pig were analyzed by
RAPD. The proportion of polymorphic loci, mean heterozygosity, dendogram, principal coordinate
analysis and minimum spanning tree were obtained. All four pigs developed viable cysticerci; the percentages of infection, obtained by the ratio of eggs used and all cysticerci counted in each pig, varied
from 0.2 to 4.2; in general, polymorphic loci proportion (0.14–0.55) and average expected heterozygosity (0.06–0.22) displayed higher values than those reported in the literature. The dendogram clustered
cysticerci into two main groups, and minimum spanning tree allowed corroboration of the data obtained
in the dendogram, and gave a better discrimination because all cysticerci from each tapeworm were
clustered among themselves. Cysticerci recovered from experimental infections might have a higher
polymorphic genetic pool than those coming from natural infections, because environmental factors and
genetic selection agents present in nature, influence natural infections, but do not participate in experimental ones.
126
What Is Delusional Parasitosis? (I). O.M. AMIN, Parasitology Center Inc., Tempe AZ, USA.
We have been seeing an increasing number of patients with pathogenic bacterial and fungal infections
associated with recurrent open skin sores/lesions and with crawling and tingling (pin prick) sensations,
often interpreted as and confused with the presence and movements of parasites under the skin and in
body cavities. The presence of parasites could not be substantiated upon thorough testing. Patients were
classified by health care practitioners as delusional. They were found to represent, however, genuine
clinical cases, but not of parasitic infections. Our studies of a few hundred patients over the last seven
years have resulted in the description and incrimination of a new disease, Neuro-Cutaneous Syndrome
(NCS) as the cause of “delusional parasitosis.” NCS is a dental toxicity disorder caused by the use of
toxic liners (bases or sealants), adhesives, cements, and related dental materials during routine dental
procedures, e.g., fillings, root canals, etc. NCS is an epidemic in disguise that affects many people,
subject to their degree of reactivity.
127
What Is Delusional Parasitosis? (II). O.M. AMIN, Parasitology Center Inc., Tempe AZ, USA.
More than 20 cases of NCS are presented here. They show variable degrees of hyper-reactivity depending
on their level of sensitivity to the toxicity of the dental materials used, how much of it was used, and how
long they have been in place. Symptoms, dental materials used and mode of their action, and associated
opportunistic infections are discussed. Relationships to dental sites, storage organs, and use of recreational drugs also are reported. Testing and treatment protocols are presented along with a number of
case histories highlighted with photos of patients before and after rehabilitation. All patients who have
followed and completed our protocol have invariably recovered.
128
Host Genetic Background Alters Sex Ratios and Genotype Patterns in a Complex-life Cycle Parasite. M.
ZAVODNA*, G.J. SANDLAND and D.J. MINCHELLA, Department of Biological Sciences, Purdue
University, West Lafayette IN, USA.
For parasites that require a number of hosts to complete their development, genetic interplay with one
host may impact parasite establishment, transmission and population genetic structure in their subsequent hosts. In this study, we address whether the genetic background (assessed via microsatellite loci) of
snail intermediate hosts influences life-history traits and genetic patterns of dioecious trematode parasites
in their definitive hosts. We performed experimental Schistosoma mansoni infections utilizing two allopatric populations of Biomphalaria glabrata snails and assessed the intensities, sex ratios and genetic patterns
of adult parasites in mouse definitive hosts. Our results provide the first evidence that the genetic
background of hosts at one point in a parasite’s life cycle can significantly impact the intensities and
genetic structure of parasites in subsequent hosts.
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129
Expression Profiling and Binding Properties of Fibrinogen-related Proteins (FREPs), Plasma Lectins From
The Snail Biomphalaria glabrata, The Intermediate Host of Human Blood Fluke Schistosoma mansoni.
S. ZHANG*, Y. ZENG and E.S. LOKER, Department of Biology, The University of New Mexico, Albuquerque NM, USA.
To gain insight into the function of fibrinogen-related proteins (FREPs), plasma lectins present in the
snail Biomphalaria glabrata, an intermediate host for the human blood fluke Schistosoma mansoni, recombinant FREP proteins were produced in vitro in bacteria. Antibodies were raised against the corresponding recombinant FREPs. Using the newly developed antibodies, we show that most, but not all FREP
proteins form as multimeric proteins in snail hemolymph. Our Western blot analyses reveal the differential expression of multiple FREPs or individual FREP protein (e.g., FREP4) in the hemolymph of S.
mansoni resistant and susceptible snail strains after exposure to the trematode Echinostoma paraensei or S.
mansoni. Finally, binding assays demonstrate that snail plasma FREP proteins were able to bind to a
variety of microorganisms, trematodes and their derived components. This suggests that FREPs may
play a role in defense against a wide range of pathogens from prokaryotic to eukaryotic organisms. The
observation that different types of microorganism were bound by specific FREP populations suggests
that there is a recognition specificity of FREPs to invading microorganisms.
130
Co-infection and Its Consequences For Host and Parasite Life Histories. G.J. SANDLAND*, J.K.
RODGERS and D.J. MINCHELLA, Department of Biological Sciences, Purdue University, West
Lafayette IN, USA.
Co-infection of host organisms by multiple parasite species has evolutionary consequences for all participants in the symbiosis. In this study, we co-exposed aquatic snails (Biomphalaria glabrata) to two of their
trematode parasites, Schistosoma mansoni and Echinostoma caproni. In co-exposed snails, E. caproni prevalence was 63% compared to only 23% for S. mansoni. Co-exposed E. caproni-infected snails exhibited
reduced fecundity, higher mortality, and higher parasite reproduction (higher virulence) compared to
hosts exposed to echinostomes alone. Conversely, co-exposed S. mansoni-infected snails released fewer
parasites and produced greater numbers of eggs compared to hosts exposed to S. mansoni alone. These
results suggest that co-exposure not only influences the establishment (presence or absence) of particular
parasite species, but also impacts host life history, parasite reproduction, and the virulence of the interaction.
131
Transcriptomics of Biomphalaria glabrata, Snail Host of Schistosoma mansoni. B. HANELT*, C. LUN and
C.M. ADEMA, Department of Biology, The University of New Mexico, Albuquerque NM, USA.
The prominent role of gastropod intermediate hosts in transmission and subsequent epidemiology of
schistosomiasis merits detailed study of the biology of the snail Biomphalaria glabrata. Along with
ongoing efforts that include molecular methods, current sequencing of the genome of B. glabrata is
anticipated to yield extensive novel data. Interpretation of this sequence information, especially as it
relates to the biology processes that function in the context of snail–schistosome immune interactions
and compatibility, will depend considerably on the study of the transcriptome of B. glabrata. Cataloguing
the transcripts that are expressed by the snail will inform on the genomic sequence by aiding gene
finding and prediction. Additionally, analysis of the response to various pathogens and parasites will
reveal aspects of the immune function (effectors and regulation) of B. glabrata. In this study, we analyzed
10,000 ESTs collected from B. glabrata snails exposed to various pathogens (schistosomes and bacteria).
In addition to providing examples of (groups) of immune-relevant genes, these data helped describing
the molecular biology of this snail intermediate host. An approach at this scale may reveal relevant
patterns of the transcriptome if parasite–host compatibility depends on multiple factors. Results will be
presented in light of parasite–host interactions. (Supported by NIH RO1 AI052363.)
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132
Morphology Shows Phylogenetic Concordance Between the Genera of Fish Blood Flukes (Digenea:
Aporocotylidae) and the Primary Lineages of Non-tetrapod Gnathostomes. S.A. BULLARD, Gulf Coast
Research Laboratory, The University of Southern Mississippi, Ocean Springs MS, USA.
“Fish blood flukes” are an ancient and taxonomically diverse group of digeneans that infect an array of
distantly related, non-tetrapod gnathostome lineages or “fishes.” Although aporocotylids have drawn the
occasional, but fleeting interest of taxonomists for more than107 years, and although taxonomic interest
in the group is presently high, aporocotylids have yet to be the focus of a phylogenetic analysis. Herein, I
present the first phylogenetic hypothesis for the genera of Aporocotylidae and compare that phylogeny
with the most widely accepted phylogeny for Gnathostomata. The foundation of this work comprises
dissections of more than 2,500 individual fish of more than 200 species in 122 genera, 67 families, and
20 orders from marine and estuarine systems in the northwestern and eastern Atlantic Ocean, eastern and
western Pacific Ocean, Sea of Cortez, Gulf of México, Caribbean Sea, and Mediterranean Sea as well as
from lakes and rivers in North America, South America, and Africa. The strict consensus tree of the 22
most parsimonious trees generated from the analysis of 204 unordered, unweighted morphological
characters and 36 taxa, including two outgroups, indicated that (1) phylogenetic host specificity among
aporocotylids is structured at the level of higher order gnathostome subdivisions, (2) basal aporocotylids
infect basal gnathostome lineages, (3) highly derived aporocotylids infect highly derived gnathostome
lineages, (4) most of the basal aporocotylids infect freshwater fishes, and (5) probable host switching
events may involve euryhaline fishes acquiring freshwater fish blood flukes. This pattern may have been
obscured previously by the void of information on aporocotylids that infect primitive gnathostomes,
collections that targeted euteleost aporocotylids, and incomplete taxonomic descriptions. (Work supported by the National Science Foundation under Grant Nos. 0508856 and 0608603.)
133
A Review of the Genus Patagifer Dietz, 1909 (Digenea: Echinostomatidae), Parasites of Birds. A.
FALTYNKOVA*, Biology Centre, Institute of Parasitology, Academy of Sciences of the Czech Republic,
„eské Bud•jovice, Czech Republic, A. KOSTADINOVA, Central Laboratory of General Ecology,
Bulgarian Academy of Sciences, Sofia, Bulgaria, and T. SCHOLZ, Biology Centre, Institute of Parasitology, Academy of Sciences of the Czech Republic, „eské Bud•jovice, Czech Republic.
The genus Patagifer Dietz, 1909 is revised, its generic diagnosis is amended, and a key to the species is
included. The type-species, Patagifer bilobus (Rudolphi, 1819), as well as P. parvispinosus Yamaguti, 1933,
P. chandrapuri Srivastava, 1952 and P. vioscai Lumsden, 1962 are redescribed on the basis of museum and
newly collected material. The variations in the number and size of the collar spines and other metrical
characters in P. bilobus are studied in two host species from Europe, Plegadis falcinellus and Platalea
leucorodia. Other valid species recognised are: P. consimilis Dietz, 1909, P. acuminatus Johnston, 1917, P.
fraternus Johnston, 1917, P. wesleyi Verma, 1936, P. brygooi Richard, 1964, P. toki Onda, Imai & Ishii,
1983, plus a new yet undescribed species. P. plegadisi Sakla, Monib & Mandour, 1988 and P. simarai
Nigam, 1944 are considered synonyms of P. bilobus and P. sarai Saksena, 1957 is placed in synonymy
with P. chandrapuri. Forms considered species inquirendae are: P. bilobus of Machida (1966), P. simerai [sic]
of Mehra (1980), P. skrjabini Hilmy, 1948, P. srivastavai Peter, 1954, Patagifer sp. of Odening (1962) and
Patagifer sp. of Gupta & Mehrotra (1971). The list of all records for the 11 valid species is compiled and
presented with comments on the hosts and the geographical distribution. The geographical range of
Patagifer spp. extends to the Americas, Europe, Africa, Asia and Australia with the bulk of the species
originally described and recorded in Asia (five species). The life-cycle of P. bilobus is known only; cercariae in Planorbis planorbis and metacercariae in other pulmonate and prosobranch snails were recorded
in Russia and the Ukraine (rivers Dnepr, Dniestr).
134
Monogeneous Parasites from Centropomus undecimalis and C. parallelus from Tabasco State. S.
LÓPEZ-JIMÉNEZ* and L. GARCIA-MAGAÑA, División Académica de Ciencias Biológicas, UJAT,
Villahermosa, Tabasco, México.
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ABSTRACTS
White snook and the snook known as chucumite, Centropomus undecimalis and C. parallelus have great
commercial importance in Tabasco State constituting fisheries in which they capture them so much in the
coastal lagoons, tidelands, and in the numerous rivers that end to these lagoons in the Gulf of México.
Nowadays in the State, as in other zones of the country, research projects are developing in order to start
to cultivate as test the snook, especially the white snook. From other research done in other zones of the
State, no species had been registered of monogeneo as parasite the gills of snooks, for which in this work
our aim was studying that species of monogeneos that are as parasite the gills of these fish species. A
review of the gills of 11 withe snooks was done of (C. undecimalis) and eight of the C. parallelus specie
proceeding from the surrounding areas of the Station of the Reserve of the Biosphere “Centla’s marshes,”
of which they found two species: Rhabdosynochus rhabdosynochus and a species of the Microcotyle genre,
which is subject to review to determine to what species it belongs since this constitutes a new record of
this genre of helminth in the snook it so much inside like out of the country. The prevalence found for
Microcotyle sp. was 45% in C. undecimalis and 37% for C. parallelus, whereas the abundance belonged to
11.7 and to 0.37, respectively. For Rhabdosynochus rhabdosynochus, the prevalence was 36% in C. undecimalis and 12% for C. parallelus, whereas the abundance belonged to 1.0 and to 0.12, respectively. It is
considered necessary to continue realizing parasitologics studies of the snooks in other regions of the
State to determine the parasite of these species of great economic importance.
135
Pathological and Histological Changes Occuring in the Liver of Various Bird Species Infected with the
Opisthorchid Trematode Amphimerus elongatus. M.C. STERNER, III*, C. METEYER, N. THOMAS, V.
SHEARN-BOCHSLER and R. COLE, USGS National Wildlife Health Center, Madison WI, USA.
Amphimerus elongatus, an Opisthorchid trematode, has been reported in three species of birds and various
waterfowl in the literature. From 1993 to 2006, the National Wildlife Health Center (NWHC) diagnosed hepatic trematodiasis caused by A. elongatus in Phalacrocorax auritus (double-crested cormorant),
Gavia immer (common loon), and Haliaeetus leucocephalus (bald eagle). The birds ranged from 17 days of
age to adults and were collected in Minnesota, Wisconsin, Maine and New Hampshire. Pathological
changes in the liver of a double-crested cormorant (P. auritus) have been documented in the literature;
however, to date, no one has compared pathological changes across species. In the six birds examined at
the NWHC, one of the eagles had little pathology, but the other three and the cormorant had enlarged
livers with rounded margins. The capsular surfaces were nodular with areas of depression and numerous
sinuous tracts that were either white or deep green to black. Pale foci with dark centers also were seen in
the eagles. Microscopic changes consisted primarily of granulomas with centers of necrotic cellular
debris, often containing trematode eggs, trematode pigment and, occasionally, colonies of bacteria. These
necrotic centers were surrounded by multinucleated giant cells, which, in turn, were surrounded by
fibrous connective tissue and inflammatory cells. In addition, the delicate structures of gravid trematodes
were present within portal areas with peripheral compression of hepatocytes. This trematode uses fish as
a second intermediate host and the metacercariae are very resistant. Thus, the piscivorous habits of birds
are the common risk factor that all these birds share.
136
Evolution of the Family Fasciolidae Railliet, 1895. W.M. LOFTY, Parasitology Department, Medical
Research Institute, Alexandria, Egypt, S.V. BRANT*, Department of Biology, The University of New
Mexico, Albuquerque NM, , USA, T.H. LE, Immunology Department, Institute of Biotechnology,
Hanoi, Vietnam, A. DEMIASZKIEWICZ, Witold Stefanski Institute of Parasitology, Polish Academy of
Sciences, Warszawa, Poland, J.M. KINSELLA, HelmWest Laboratory, Missoula MT, USA, and E.S.
LOKER, Department of Biology, The University of New Mexico, Albuquerque NM, USA.
Members of the family Fasciolidae are rather large, leaf-shaped trematodes that parasitize mammals (e.g.,
cattle, pigs, deer, sheep, elephants) as definitive hosts. The adults are found mainly in the liver or bileducts; however, two species are known to occur in the small intestine. It is remarkable that, although
species in this family are responsible also for disease in both human and domesticated animals, there is no
modern systematic treatment. Using internal transcribed spacer 1 and 2 (ITS) rDNA and NADH
dehydrogenase subunit 1 (ND1) mtDNA, the phylogenetic relationships among genera in the family
Fasciolidae were reconstructed. Monophyly of the family and the three recognized subfamilies was
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supported. Protofasciola, which occurs in the small intestine of elephants, was the basal genus. Although
the snail intermediate host of Protofasciola is yet unknown, the other basal genera, Fasciolopsis and Parafascioloides, use planorbid snails. Fascioloides and Fasciola were derived and are found in the bile-duct of
their mammalian host and use lymnaeid snails as intermediate hosts. In light of these results, host–
parasite coevolution will be discussed.
137
Genetic Variability in Members of Didymozoidae Family Isolated from Two Bluefin Tuna Species. I.
MLADINEO* and B. BLOCK, Hopkins Marine Station, Stanford University, Pacific Grove CA, USA.
Atlantic (Thunnus thynnus) and Pacific bluefin tuna (Thunnus orientalis) are migratory marine teleosts
that are declining in abundance due to overexploitation in the Atlantic and Mediterranean Sea. Recently,
molecular and electronic tag data have shown that at least two populations exist in the North Atlantic
and mix on foraging grounds in the North Atlantic. One population spawns in the Gulf of México and
the other spawns in the Mediterranean Sea. Tuna also comprises the most valuable finfish aquaculture
product currently recognized, with the production accounting for more than a half of the world total,
concentrated in the Mediterranean Sea. While the use of parasites as natural tags is not a novel practice,
it is employed mainly to assess stocks of fish taxa with high commercial value (hake, Atlantic cod,
rockfish). In past studies, bluefin tuna parasite communities were assessed both in wild and reared fish,
showing remarkable prevalence/ abundance of Didymozoidae (Trematoda, Digenea). They parasitize a
wide number of tissues (body surface, fins, mouth and gill cavity, visceral organs and kidney) and are able
to elicit pathological effect in reared fish. Given the wide geographical distribution of bluefin tuna and
substantial efforts to distinguish between the stocks, we analyzed molecular variation in 63 Didymozoidae members using mitochondrial (COI) and genomic markers (28S rDNA and ITS). Forty-four
specimens were collected from Atlantic bluefin tuna reared in Adriatic Sea pans, and 19 were sampled
from Pacific bluefin tuna reared in the Gulf of México. The aim of the study was to discern if the genetic
diversity of Didymozoidae is correlated with the origin of the bluefin from the Mediterranean or Gulf of
México stock, in order to assess the usefulness of didymozoans as biological tags. In contrast with
previous results on genetic diversity of digenea Cradicola forsteri and monogenean Hexostoma thynni from
four tuna species, our results showed evidence in favor of genetic divergence between didymozoids from
Gulf of México and Adriatic Sea, respectively.
138
Transmission Dynamics of Cyathocotyle bushiensis (Trematoda: Cyathocotylidae) and Sphaeridiotrema
globulus (Trematoda: Psilostomatidae) in Pool 7 of the Upper Mississippi River National Wildlife and
Fish Refuge. K.K. HERRMANN* and R.E. SORENSEN, Department of Biological Science, Minnesota
State University, Mankato MN, USA.
Recurrent mortality of migrating waterbirds, primarily lesser scaup (Aythya affinis) and American coot
(Fulica americana), has been occurring in Pool 7 of the Upper Mississippi River National Wildlife and
Fish Refuge since 2002. The mortality is associated with two trematodes, Cyathocotyle bushiensis and
Sphaeridiotrema globulus. Birds become infected by ingesting metacercariae-infected Bithynia tentaculata
snails, an invasive species that serves as first and second intermediate host for both trematode species.
This study examined temporal and spatial patterns in the transmission and distribution of C. bushiensis
and S. globulus around Arrowhead and Broken Gun Islands in Pool 7. A total of 2,970 snails were
collected during six dates in 2005 and 2006. Bird hosts, 18 of each species, were collected in the fall of
2005. Prevalence and abundance in the snail host population varied among dates and sites. During the
fall of 2005, the abundance of mature metacercariae of C. bushiensis at 5.76 ± 0.621 metacercariae per
snail was greater than the abundance of S. globulus at 3.51 ± 0.355 metacercariae per snail. All 18 coot
examined were infected with C. bushiensis, but only one was infected with S. globulus. All 18 scaup
examined were infected with S. globulus, and 16 were infected with C. bushiensis. The abundance of C.
bushiensis was greater in coot at 107.9 ± 17.97 worms per bird than in scaup at 36.6 ± 8.79 worms per
bird. Conversely, abundance of S. globulus was greater in scaup at 3,440.1 ± 582.93 worms per bird than
in coot at 0.2 ± 0.17 worms per bird. The ratio of metacercarial abundance of C. bushiensis to S. globulus
of 1.64:1 is not the same ratio found in the bird hosts. In contrast, the ratio of C. bushiensis to S. globulus
is 108:1 in coot, but only 0.01:1 in scaup. This suggests that the ratio found in bird hosts is affected by
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host susceptibility and that susceptibility to these two trematode species is very different between coot
and scaup.
139
Spatial and Temporal Abundance Patterns of the Common Grass Shrimp Palaemonetes pugio, and the
Trematode Parasite, Microphallus turgidus in the North Central Gulf of México. K.L. SHEEHAN*,
Dauphin Island Sea Lab, Dauphin Island AL, and Department of Marine Sciences, University of South
Alabama, Mobile AL, J. O’BRIEN, Department of Biological Sciences, University of South Alabama,
Mobile AL, J. CEBRIAN, Dauphin Island Sea Lab, Dauphin Island AL, and Department of Marine
Sciences, University of South Alabama, Mobile AL, USA.
This study was undertaken to understand how biological and environmental parameters may affect the
prevalence and intensity of the trematode, Microphallus turgidus, in its second intermediate host, the
common grass shrimp, Palaemonetes pugio, in the marshes of Mobile Bay, Alabama. Regional surveys of
habitats throughout the Bay during winter and spring of 2007 documented that the distribution of P.
pugio differed significantly among habitats, as did the prevalence of metacercarial larval stages of the
trematode, M. turgidus. Parasite abundance and prevalence varied with salinity, season, and host size.
Two shrimp populations within the Mobile Bay have been sampled periodically since March 2006: a
dredge spoil island (Gaillard Island) that serves as a brown pelican rookery and a nearby marsh creek
(Deer River) on the mainland. Trematode prevalence was always lower on the island [Gaillard Island,
maximum 12%; Deer River, minimum 25%] and prevalence in both populations was higher during
summer than winter. Water column, pore water, and sediment samples were collected from both sites.
Nutrient concentrations in the water column and pore water were elevated on Gaillard Island during
nesting season. One of many explanations under consideration is that although birds nesting on Gaillard
Island may be a source of trematode eggs, the degree of guano produced by the rookery may raise
nutrient concentrations to toxic levels that may somehow impede the ability of M. turgidus to infect
successfully populations of either the first intermediate host (hydrobiid snails) or P. pugio. The higher
prevalence of M. turgidus in P. pugio at Deer River supports this hypothesis. Birds visit, hunt, and
defecate eggs at the mainland site, but nutrient concentrations do not become as elevated as on the island
because the birds do not roost there. This investigation provides information regarding the magnitude of
spatial and temporal variability of the prevalence of M. turgidus in P. pugio that may be related to the
presence/absence of a shorebird rookery.
140
Patterns of Eugregarine Infection in Damselflies (Odonata: Coenagrionidae) of the Texas Big Thicket. S.
DAHLGREN*, T.J. COOK, Department of Biological Sciences, Sam Houston State University, Huntsville
TX, and R.E. CLOPTON, Department of Natural Science, Peru State College, Peru NE, USA.
Eugregarines are apicomplexan parasites of invertebrates. Most species have been described from insects
and typically infect the midgut. As part of a larger inventory of eugregarine diversity within the Texas Big
Thicket, we examined the infection patterns in 17 species of damselflies. We identified differences in
eugregarine prevalence between the 14 species of damselflies collected in 2006 and compared these
results with prevalence data from 10 species collected in 2005, and discuss possible explanations for
variability. Within a host species, we compared prevalence between collection sites, and in instances
where we collected both adults and naiads, we compared prevalence across stadia. In 2006, Argia sedula
and A. translata had prevalence levels of 81.3% and 92.5%, respectively. Neither of these species was
collected the previous year and A. moesta, which was collected the previous year with 100% prevalence,
was not collected in 2006. Overall, the genus Argia demonstrates the highest overall prevalence per
species. Enallagma basidens, E. civile, E. daeckii, E. divagans, E. traviatum and E. vesperum were all collected in 2006, with prevalence varying from 0% to 83.3%. Unlike 2005, E. dubium, E. exulsans and E.
signatum were not collected in 2006, but E. civile and E. daeckii were. The great variation in prevalence
may be accounted for by the greater diversity of species caught within the genus. Prevalence for Ishnura
hastata and I. posita changed from 23.6 to 28.3% (2005 to 2006) and from 29 to 21.2%, respectively. L.
kellicotti and L. ramburii were collected in 2006 with a 0% prevalence. This may be due, in part, to a
small sample size for each species. A new species collected in 2006 was Nehalennia integricollis, with a
53.8% prevalence.
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ABSTRACTS
141
Patterns of Gregarine Infections of Argia spp. (Odonata: Zygoptera) Across Biogeographical Provinces in
Texas. J.J. HAYS*, T.J. COOK, Department of Biological Science, Sam Houston State Universtiy, Huntsville TX, and R.E. CLOPTON, Department of Natural Science, Peru State College, Peru NE, USA.
Gregarines (Apicomplexa: Eugregarinida) are ubiquitous parasites of invertebrates, especially insects.
Gregarines are typically thought to be highly host-specific, leading some authors to propose a “one host,
one gregarine species” model. More than 20 gregarine species have been described from the insect order
Odonata (dragonflies and damselflies) in the Old World, but only six species have been described from
odonates in the Western Hemisphere. Preliminary sampling in Primitive Big Thicket of East Texas has
identified numerous odonate species infected with gregarines. Our project focuses on gregarines in the
damselfly genus Arigia, which is widely distributed in, but limited to the New World. In 2006, we
recovered gregarines from four species of Arigia: Arigia translata, Argia sedula, Argia moesta and Argia
tibialis. Based on morphological data, it appears that gregarines infecting A. translata and A. sedula are
the same species, but that the gregarines infecting the other two species of Argia are different from each
other and from the species infecting A. translata and A. sedula. Based on these preliminary results, we are
investigating the nature of host specificity of gregarines parasitizing Argia spp. across biogeographic
provinces in Texas and latitudinal gradients in North America. (Supported by NSF Grant
DEB0340782.)
142
Geographical and Ecological Distribution Patterns of Leishmania Vectors in México. C. GONZÁLEZROSAS*, Instituto de Biología, UNAM, México DF, I.D. BECKER, Unidad de Medicina Experimental,
Facultad de Medicina, UNAM, México DF, E. MARTÍNEZ-MEYER and V. SÁNCHEZ-CORDERO,
Instituto de Biología, UNAM, México DF, México.
The Leishmaniases consist of a group of diseases caused by at least 13 species of parasites of the genus
Leishmania, which are transmitted to humans by phlebotominae blood-feeding female insects. The
disease may take different forms depending on the parasite species involved: visceral, muco-cutaneous,
and cutaneous (diffuse or located). The WHO reports at least two million cases each year: 1.5 million
involving the cutaneous form and 500,000 the visceral form. Their distribution is highly related to
anthropogenic environmental changes, favoring an increase in vector, parasite and reservoir abundances.
Species’ ecological niche modeling projected as potential distributions (EN) offers new insight for
identifying risk areas and, consequently, priorities for launching programs for disease prevention. Here,
we modeled the EN projected as potential distributions of the main vectors of visceral leishmaniasis in
México and Colombia, and those of cutaneous leishmaniasis in México, using point occurrence data,
environmental digital coverages, and a GIS platform. We used the comuter algorithms MaxEnt (Maximum Entropy Modeling) and GARP (Genetic algorithm for rule-set prediction) software packages
(http://homepages.
inf.ed.ac.uk/s0450736/maxent.html; http://nhm.ku.edu/desktopgarp/). Species suspected of being
involved in the transmission of cutaneous leishmaniasis in México showed a wide geographical distribution, with two prominent regions located in the northern and southern limit of the country. The visceral
form of the disease showed different distributions of the two species involved, L. longipalpis and L. evansi,
and they vary between geographical regions. GARP tended to predict larger areas of potential distribution than MaxEnt. We discussed the applicability of species’ ecological niche modeling in public health
control and prevention.
143
Effects of UVB on Larvae of Schistosoma mansoni and the Snail Host, Biomphalaria glabrata. D.S.
RUELAS*, D. KARENTZ and J.T. SULLIVAN, Department of Biology, University of San Francisco, San
Francisco CA, USA.
Although Schistosoma mansoni occurs mainly in the tropics, where intense levels of solar radiation are
present, the effects of ultraviolet (UV) light on schistosome transmission are not known. The purpose of
this study was to investigate potential effects of UVB (290–320 nm) on aspects of the life cycle of S.
mansoni. Larval schistosomes (miracidia) and the snail intermediate host (Biomphalaria glabrata) were
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exposed to measured doses of UVB from UV-fluorescent lamps, and the following were measured: snail
survival, parasite development, photoreactivation (light-mediated DNA repair), effects on snail innate or
acquired resistance to infection, and effects on snail behavior. Exposure to UVB is lethal to B. glabrata in
a dose-dependent manner. The shell offers some, but not complete protection. Wild-type (pigmented)
snails are less susceptible to lethal effects of UVB than albino snails, and they may be more capable of
photoreactivation. UVB, however, does not affect the innate resistance to infection with S. mansoni in
genetically resistant snails, nor do UV-irradiated schistosome miracidia induce acquired resistance in
susceptible snails; both negative results are similar to those reported using ionizing radiation. UVB
affects the development of S. mansoni such that, at high doses, infection is retarded or does not occur,
and most irradiated parasites degenerate and die within the snail. Sporocysts are able to photoreactivate,
even at three days post-infection. Finally, UVB exposure inhibits snail feeding behavior, and causes
abnormalities (branching) in snail tentacles. Thus, UVB may influence the life cycle of S. mansoni by
affecting parasite development, snail survival, and snail behavior. The ability of both snails and parasites
to photoreactivate, however, may mitigate these effects. (Supported by NIH grant AI 50546, and by the
Fletcher Jones Foundation.)
144
The Interface Between Public Health and Parasitology: Bridging the Gap. M. EBERHARD*, Division of
Parasitic Diseases, CDC, Atlanta GA,USA.
Prevention of disease, the hallmark of public health, is based on sound science and hard data, generated
through research and epidemiologic study. At the core of public health, and effective prevention and
control, is the need for basic understanding of parasite biology, life cycle, mode of transmission, pathology, host factors, and, in some cases, an understanding of intermediate host(s). In the United States,
three infections, Babesia, Cryptosporidium and Cyclospora, serve to highlight how basic parasitology has
contributed to public health efforts to control these infections. Yet these same infections also provide
striking examples of where much basic biology is still needed and the absence of this information poses
real challenges to public health. These three infections also highlight vulnerabilities related to blood,
water and food safety, respectively. Water safety, further subcategorized into areas of drinking water and
recreational water, along with food safety, also engage components of bioterrorism preparedness (intentional harm). By contrast, we have considerably more understanding of the basic biology of several
parasitic infections, known since antiquity, such as malaria, Guinea worm, lymphatic filariasis, and
onchocerciasis. For these infections, proven, sustainable and relatively inexpensive interventions exist,
and massive country or region-wide control programs are under way, and for several, we are on the verge
of global eradication or regional elimination. As efforts to reduce the burden of these diseases progresses,
there are important, relevant research questions remaining for parasitologists to address. Nonetheless,
these control programs provide excellent opportunities to reduce the burden these diseases cause. The
level of renewed interest, both domestically and globally, in parasitic diseases provides an incredible
opportunity for scientists engaged in public health and parasitology to contribute to these efforts. The
interface between parasitology and public health continues to be dynamic and the need for parasitology
research as great as ever, particularly in the areas of food, water, and blood safety. Parasitologists will
continue to bridge this gap between public health and other allied disciplines to explore new areas,
conduct research, and provide critical answers that will effectively move public health forward with the
control and prevention of parasitic diseases.
145
Spiral Intestine Cestodes in the Piked Dogfish (Squalus acanthias) Across Space and Time. M.
PICKERING* and J.N. CAIRA, Ecology and Evolutionary Biology, University of Connecticut, Storrs CT,
USA.
The squaliform shark, Squalus acanthias, is one of the few elasmobranch species that appears to exhibit a
truly cosmopolitan distribution and thus can serve as a source of information on the cosmopolitan nature
of cestode species and seasonal variation in cestode faunas globally. The literature includes extensive data
on the cestode fauna of S. acanthias from coastal Ireland, and minimal published data are available from
other locations, including New Zealand, the North Sea, the Black Sea, and the Mediterranean Sea. By
compiling these past records and augmenting them with data from new collections from Japan, Alaska,
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ABSTRACTS
New Zealand, New England, and Chile, we can begin to trace cestode infections through space and time.
In total, three cestode species have been found to infect the spiral intestine. These are the two tetraphyllideans, Phyllobothrium squali and Trilocularia acanthiaevulgaris, and the trypanorhynch, Gilguina
squali. At least the latter two species appear to be cosmopolitan. Cestode prevalence was found to vary
among locations and between seasons. Published data from Ireland support the existence of a seasonal
cycle in T. acanthiaevulgaris. Winter prevalence of T. acanthiaevulgaris was found to be greater in New
England than reported from Ireland (46% vs. 11%). Trilocularia acanthiaevulgaris prevalence was found
to range from zero (n = 5) in New England in spring to 57% (n = 7) in New Zealand in summer.
Gilguina squali prevalence ranged from zero in New England in spring and Japan in fall (n = 5 and 7), to
76.9% (n = 13) in New England in winter. Phyllobothrium squali was found to be the least ubiquitous,
occurring only in Japan in fall (42.8%, n = 7), New England in spring (40%, n = 5), and Alaska in
summer (7.7%, n = 13). It also exhibited the lowest mean abundance (0.18 vs. 0.9 for T. acanthiaevulgaris and 1.45 for G. squali). These results suggest that intraspecific comparisons of infection parameters across seasons and broad geographic ranges are productive lines of investigation.
146
Parasite Communities of the “Checkered Puffer” Sphoeroides testudineus from Coastal Lagoons of
Yucatán, México. M.T. SOSA-MEDINA* and L. AGUIRRE-MACEDO, CINVESTAV, Lab. Patología
Acuatica, Depto. Recursos del Mar, Mérida, Yucatán, México.
The parasites of the “Checkered puffer,” Sphoeroides testudineus, were studied at component community
and infracommunity levels in four coastal lagoons from Yucatán, México during the dry season of 2005.
Sampling was conducted using a 15-m-long beach seine with a 2.5-cm mesh. A total of 211 fish were
collected. Parasite species composition, richness and diversity were used to compare parasite communities between and within lagoons. A total of 2,391 parasites belonging to 14 species were recovered: one
monogenean, seven trematodes, one cestode, four nematodes, and one acanthocephala. From all species
found, seven were larval stages and seven were adults; two species were allogenic and 12 autogenic. The
majority of the species found were generalist. At the component level, species richness was between
seven and eight species per sampled site, and the Simpson’s diversity index was between 0.441 and
0.554. Values of Jaccard index qualitative similarity and quantitative percentage of similarity were above
47.96%. At the infracommunity level, species richness was between 2.290 ± 1.30 and 3.034 ± 1.010
and Brillouin’s diversity between 0.040 ± 0.081 and 0.149 ± 0.142. Similarity, at this community level,
it ranged between 40.9% (± 43.4) and 64.2% (± 41.4). There were no significant differences in any of
the community parameters between lagoons. Trematodes were the most dominant group in all communities; the metacercariae of Apharingostrigea sp. and Stephanostomum sp. were the only species present in
the four coastal lagoons; nevertheless, a large number of species were present in at least three of four
lagoons, suggesting a high parasite exchange between and within lagoons.
147
Spatial Structure of the Helminths of Tonguefish Symphurus plagiusa on the Campeche Coast, Gulf of
México. A. RODRÍGUEZ GONZÁLEZ* and V.M. VIDAL MARTÍNEZ, Departamento de Recursos del
Mar, CINVESTAV-IPN, Unidad Mérida, Yucatán, México.
The distribution of the organisms in a space can exhibit some type of spatial structure (random, uniform
or aggregated) as a result of the influence of environmental variables in restricted areas. The information
about the influence of spatial structure over helminths of marine fish is practically nil. Thus, our aims
were to determine if there is a spatial structure in the abundance of two helminth species of S. plagiusa, as
well as to determine possible associations between environmental and biotic variables in a spatially
structured environment. The helminths considered were the most frequent and abundant species in S.
plagiusa: the metacercariae Stephanostomum sp. and the larval cestode Trypanoryncha gen. sp. The data set
was built by sampling monthly (May to September, 2003) 37 sites along the Campeche coast. The data
were analyzed with SADIE, a program that generates indices of spatial aggregation. The main advantage
of SADIE is that it allows determination of possible correlations between the abundance of the organisms (helminths) and environmental parameters, while controlling the spatial autocorrelation. Significant
correlations between environmental variables and helminth abundance means that the former can be
influencing the spatial distribution of the latter. This, in turn, means that these helminths would be living
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ABSTRACTS
in a spatially structured environment. Significant positive spatial associations were found between the
abundance of Stephanostomum sp. and depth in May, June and September. There also were significant
positive correlations between the abundance of Trypanoryncha gen. sp. and depth in May, June, July and
September. There also were positive correlations between salinity and the abundance of Stephanostomum
sp. and Trypanorhyncha gen. sp. from May to September. The results suggest that the spatial structure of
these two helminth species is strongly influenced by seasonal water discharges of large rivers in the study
area.
148
Assessing Factors Exerting Evolutionary Pressures on Parasite Species in Nature: The Case of Dactylogyrus. A.K. KNIPES* and J. JANOVY, JR., School of Biological Sciences, University of Nebraska, Lincoln
NE, USA.
Factors exerting evolutionary pressures on parasite species in nature are difficult to identify, though they
are presumably affecting host–parasite encounter dynamics and modes of parasite attachment. Dactylogyrus, a large genus of approximately 970 species, is distributed widely in the world, parasitizes fish
belonging to three different families, and exhibits a high degree of host-specificity, making the genus a
prime candidate for evolutionary studies likely to shed light on evolutionary factors generating diversity
in parasites. A 2004–2006 study of the community and population structures of nine Dactylogyrus
species, on three fish species, in three convergent streams in the Salt Valley Watershed of Lancaster
County, Nebraska has revealed evidence that allows one to sort through the factors that are likely to
influence the evolutionary trajectories of the parasites involved. Such factors, including morphological
diversity, host-partitioning by season, and host specificity have enabled the formulation of hypotheses as
to the selective forces at work in the system, including diversity in host gill structure, habitat variability,
limitation of resources, and low diversity of available hosts. Combined with the facilitation of transmission through selection for lifecycles that coincide with certain host behaviors, such factors are likely to
play a role in the evolution of parasite and host interactions, and ultimately the distribution of parasites
in nature.
149
Migration and Site Selection of Ornithodiplostomum ptychocheilus Metacercariae in the Optic Lobes
of Fathead Minnows. C.E. MATISZ*, Department of Biological Sciences, University of Lethbridge,
Lethbridge, Alberta, Canada, and C.P. GOATER, Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada.
Trematodes exhibit tremendous interspecific variation in the extent to which their metacercariae are site
specific. Thus, while cercariae of Strigeoid trematodes migrate to, and encyst within, highly specific
regions within host tissues, cercariae of Fasciolid trematodes encyst on almost any substrate. We do not
understand the factors that lead to this variation. Here, we characterize extreme site specificity of the
metacercariae of Ornithodiplostomum ptychocheilus (Strigeida: Diplostomidae) within the optic lobes of
the brains of fathead minnows. Electron and confocal imagery analyses involving experimentally infected
minnows indicate that diplostomules migrate along the central nervous system to the ventral regions of
the brain. Two days after exposure to cercariae, diplostomules are restricted within only one–three of a
total of 15 laminar layers of the minnow optic lobe. Specifically, diplostomules develop and ultimately
encyst within the stratum opticum. This region contains few dendrites and few cell bodies, yet it is
heavily vascularized and highly regenerative. These results indicate that metacercariae site specificity may
result from nutrient requirements associated with metacercariae growth and development.
150
Systematics and Biogeography of Indopacific Bloodfeeding Terrestrial Leeches (Hirudinida: Arhynchobdellida: Hirudiniformes). E. BORDA*, Department of Biology, City Unversity of New York, New York
NY, and M. SIDDALL, Division of Invertebrate Zoology, American Museum of Natural History, New
York NY, USA.
IndoPacific bloodfeeding terrestrial leeches, or haemadipsid leeches, are adapted to damp tropical
terrestrial environments and are ectoparasites that feed on vertebrate blood. This group of leeches is
particularly interesting because they have a strict distribution that mirrors the breakup of Gondwana.
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ABSTRACTS
Haemadipsid leeches have been classified under a single family, Haemadipsidae (Sawyer, 1986) or have
been divided into three families based on jaw morphology and geography (Richardson, 1975). There are
two major groups of bloodfeeding terrestrial leeches, including the trignathous (three-jawed) leeches,
which are distributed throughout the Indian subcontinent (below the Himalayan Mountains), East Asia
and Southeast Asia, and the duognathous (two-jawed) leeches found in isolation on Australia, Papua
New Guinea, Indonesia, Madagascar, Seychelle Islands, and the Pacific Islands, including the Juan
Fernandez Archipelago. The phylogenetic and biogeographic relationships of Haemadipsidae are assessed
based on a broad taxonomic sampling of leeches from across their range and from the combined data
analyses of nuclear 18S rDNA and 28S rDNA and mitochondrial cytochrome c oxidase subunit 1
sequence data. The combined data analyses suggest that Haemadipsidae is monophyletic and that the
duognathous haemadipsids also are monophyletic, yet are nested within a trignathous haemadipsid clade.
The monophyly of duognathous leeches may support that Haemadipsidae has origins that date back to
more than 150 MYA, before the IndoMalagasy landmass separated from Gondwana. In contrast, some
trignathous haemadipsid leeches that are distributed throughout India and Asia may have more recent
origins due dispersal and diversification events that occurred as recently as ~35–25 MYA following
India’s collision into Asia.
151
A Multi-gene, Multi-genome Approach to Inferring the Phylogeny of Members of the Apicomplexa
with Particular Reference to the Eimeriid and Adeleid Coccidia. J.D. OGEDENGBE* and J.R. BARTA,
Department of Pathobiology, University of Guelph, Guelph, Ontario, Canada.
The phylum Apicomplexa, members of which are mostly parasites, are important in understanding the
evolution of parasitism and adaptation to their hosts from marine to terrestrial habitats. Two important
members of the group include the eimeriids and the adeleids. The relationships among and within these
recognizable groups of apicomplexan parasites have been poorly understood; the adeleids, in particular,
have not benefited from molecular phylogenetic analysis, and phylogenetic hypotheses have been based
primarily on morphological details. We used aligned sequences from the nuclear 18S rRNA, plastid rPo
and mitochondrial COX I genes, individually and collectively, to infer the interrelationships among these
various apicomplexan taxa. Maximum parsimony, maximum likelihood and Bayesian methods were used
for the various analyses with appropriate taxonomic or functional outgroup taxa included. Taxa belonging to recognized groups within the Apicomplexa formed monophyletic clades. Analysis using the
individual genes reasonably resolved the various apicomplexan groups with strong bootstrap support and
high Bayesian posterior probabilities. The multi-gene, multi-genome (18S, rPo and COX I) analysis, to
which was added relevant morphological details in a total evidence approach, appeared to indicate that
some members of the Apicomplexa, especially the eimeriids, occupied similar niches in different hosts
before their present adaptive hosts. New sequences generated in our lab from marine and terrestrial
gregarines and adeleids were supplemented with additional sequences from GenBank representing a
range of other apicomplexan taxa to provide a phylogenetic reconstruction that suggests that gregarines
form a monophyletic clade with the haemosporinids and cryptosporidia, and the adeleids form a monophyletic clade with the piroplasms. These well-supported clades are at odds with classical taxonomic
groupings based solely on morphological features and highlight the value of a multi-gene, and genome,
molecular analysis for resolving evolutionary relationships among apicomplexan parasites.
152
Molecular Analysis of Acanthobothrium and Its Implications for Geographic Versus Host Associations as
Determinates of Cestode Phylogeny. C.A. FYLER*, Department of Ecology and Evolutionary Biology,
University of Connecticut, Storrs CT, USA.
The cestode genus Acanthobothrium is by far the most ubiquitous genus of elasmobranch cestodes,
parasitizing 10 of the 14 elasmobranch orders. Most species in this genus are remarkably host specific,
exhibiting essentially oioxenous specificity for their definitive hosts. A common assumption in the
parasite literature is that high host specificity will be maintained through evolutionary time, resulting in
parasite phylogenies that mirror the phylogenies of their hosts. The goal of this study was to determine if
evolution of the highly specific Acanthobothrium species is mirroring evolution of their elasmobranch
hosts. Broad geographic and host sampling of Acanthobothrium species was necessary to address this
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question. Molecular sequence data from the nuclear ribosomal subunit 28S were generated for 44
parasite species from eight elasmobranch orders collected off the coasts of Africa, North America,
Australia and Borneo. Bayesian inference and maximum parsimony were used to analyze the molecular
dataset. In all analyses, Acanthobothrium was found to form a single, well-supported clade, which consisted of three well-supported subclades. Based on these molecular results, host associations do not
appear to be determinates of phylogeny. Acanthobothrium species parasitizing an elasmobranch order
were never each other’s closest relatives. Instead, Acanthobothrium species of an order were distributed
throughout the phylogeny. The molecular results supported geography as a good determinate of parasite
phylogeny. Regardless of host associations, two of the three subclades showed strong geographic affinities, with one subclade of species being distributed throughout the Atlantic basin and Baja California,
and the second distributed in localities throughout the Indo-Pacific. These results suggest that evolution
of this diverse and host specific genus is not being driven by host ordinal relationships. Host switching
must have played a major role early on in the evolutionary history of Acanthobothrium.
153
Homoplasy in Bothridial Pouches and Its Implications for the Identity of the Tetraphyllidean Genus
Carpobothrium. K. CHRISTISON-LAGAY* and J.N. CAIRA, Department of Ecology and Evolutionary
Biology, University of Connecticut, Storrs CT, USA.
The diversity of bothridial morphologies seen among tetraphylidean cestodes has challenged cestode
systematists for decades. As in other systems, attempts to generate a natural classification for such taxa
have emphasized conspicuous and relatively unique morphological features, often to the exclusion of
other characters. Carpobothrium is an example of such a taxon. This genus has come to house species
with bothridia that bear pouches, but these species exhibit variation in other bothridial features such as
apical suckers and marginal loculi and parasitize a wide array of elsamobranchs. New collections from
sharks and rays in Borneo and Australia allowed more detailed investigation of the bothridial pouches of
taxa assigned to Carpobothrium. Pouch-bearing specimens from eight species of sharks and rays were
prepared as whole mounts and sections for light microscopy, and also were examined with scanning
electron microscopy. The results suggest that two distinct types of pouches exist among these species. In
some species, the bothridia are pedicellate and the pouch takes up the majority of the bothridium. In
such cases, the anterior and posterior regions of the bothridium can be withdrawn into the pouch. In
contrast, in other species, the bothridia are essentially sessile and the pouch occupies only the central
one-third of the bothridium; complete retraction of the anterior and posterior regions of the bothridium
into the pouch is not possible in these taxa. Thus, the pouches in these two suites of cestodes are not
homologous. Whereas species bearing the first pouch type are restricted to bamboo sharks (e.g., Chiloscyllium), species exhibiting the second pouch type parasitize batoids (e.g., Himantura and Rhina). The
erection of a new genus for species exhibiting one of the two pouch types is supported by sequence data
from 28S rDNA, which shows that species bearing the two different pouch types do not form a monophyletic group. Given that the type species of Carpobothrium exhibits the first bothridial pouch type and
was collected from Chiloscyllium indicum, the new genus is proposed for species exhibiting the second
pouch type.
154
Identification of Proteins, Using Proteomics, During the Evaluation of Potential Anti-parasitic Drugs. J.R.
AMBROSIO-HERÁNDEZ*, Dep. Microb. y Parasitol, Fac. Med. UNAM, C.A. MÉNDEZ-CUESTA, O.A.
REYNOSO-DUCOING, L. VELAZQUEZ-MÁRQUEZ, L. RUIZ-MARTÍNEZ, Dep. Microb. y Parasitol,
Fac. Med. UNAM, R. CASTILLO, F. HERNÁNDEZ, A. HERNÁNDEZ, Dep. Farmacia, Fac. Química,
UNAM, L. YÉPEZ-MULIA, Hospital de Pediatria, IMSS Siglo XXI, México, M.A. DEA-AYUELA, F.
BOLÁS-FERNÁNDEZ, Dept. Parasitología, Fac. Farmacia, UCM, España, A. PÉREZ-REYES and A.
FERRER, Dep. Microb. y Parasitol, Fac. Med, UNAM, México.
There is a lack in the development of new drugs for curing parasitic diseases, and in recent years, some
drugs used are presenting clinical resistance and secondary effects on the patients. Developing a drug is a
long and an expensive process, however, the evaluation of potential drugs could be an easier task using
new strategies such as medicinal chemistry, chemoinformatics, bioinformatics, cellular biology and
proteomics. With a multidisciplinary team, that involves chemists, parasitologists, biochemists, cellular
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biologists, we are working with designed and synthesized benzymidazole derivatives (BZM) and hybrid
molecules that combine features of nitazoxanide (NTZ) and some BZM known as carboxamides; these
BZM were tested in vitro using several parasitic models in order to evaluate their potential anti-parasite
activity and some of them were selected, because they were found in vitro to be more potent than
albendazole, metronidazole and NTZ. Parasite extracts were assessed, using 1D and 2D electrophoresis,
in order to establish changes in the expression of proteins. For G. intestinalis, approximately 500 spots
were resolved in each treated and untreated sample and, because we know the genome of G. duodenalis,
after using Mass Spectrometry (MALDI TOF-TOF), several proteins were identified. Later, using a PDQuest analysis, we found that there was an increase or decrease in the expression of several proteins; for
example, three BZM significantly reduced the expression of giardins, a group of cytoskeletal proteins,
that together with tubulins are the main components of the ventral disk and an important structure on
the flagella; these variations on protein expression correlated with observations performed by Scanning
Electronic Microscopy (SEM) of parasites. Using this parasite model, we found that these approaches
(proteomic and SEM analysis) could be useful for evaluating the action of drugs, or potential drugs, and,
at first glance, there is a good chance for learning what type of proteins involved. (Supported by
CONACYT-México [43629] and DGAPA-UNAM [IN201003 and IN216107].)
155
Genome-wide Analysis of Stage-specific Gene Expression in Leishmania. B. PAPADOPOULOU*, A.
ROCHETTE, M. MÜLLER, F. McNICOLL, F. RAYMOND, J. CORBEIL and M. OUELLETTE, Medical
Biology, Laval University, Quebec, Quebec, Canada.
Leishmania encounters drastic environmental changes during developmental switches from the free-living
promastigotes in the alimentary tract of the sand fly vector to intracellular amastigotes in the mammalian
macrophages. These developmental stages display distinct morphologic and metabolic characteristics
consistent with a highly regulated level of differential gene/protein expression, which is central to the
parasite’s intracellular survival. We have applied a genome-wide approach consisting of protein prefractionation, global proteomics and DNA oligonucleotide full-genome microarrays to analyze stagespecific gene expression both in L. infantum and L. major. Two-dimensional gel and LC-MS/MS analyses
showed that 6.1% of the L. infantum proteins were overexpressed or unique in the promastigote stage,
whereas 12.4% were increased in amastigotes. Many proteins were present in multiple spots, suggesting
that post-translational modifications or processing is extensive in this parasite. Advanced statistical
analyses identified a relatively low degree of differential mRNA expression. Comparison between L.
infantum/L. major promastigotes and intracellular amastigotes revealed that 1.5–4% of the total genes are
overexpressed in promastigotes and 2.3–2.7% are more expressed in amastigotes. Recently, we have
identified two new families of widespread extinct retroposons (~2,000) that are located predominantly
within 3′-untranslated regions of Leishmania mRNAs. We showed that members of these retroposons
could either enhance mRNA translation or promote destabilization of retroposon-bearing mRNAs.
Interestingly, a large number of developmentally regulated Leishmania transcripts carry these retroposons,
which suggests a potential link between stage-regulated gene expression and these 3′UTR elements.
Overall, these studies allowed the identification of novel genes or pathways that are developmentally
regulated and depicted novel mechanisms of stage-regulated gene expression in Leishmania. The followup studies are expected to provide new insights about the intracellular development of this parasite and
eventually lead to the identification of novel therapeutic targets.
156
A Proteomic Approach for the Analysis of Immune Proteins in Anopheles albimanus Infected with
Plasmodium. H. LANZ-MENDOZA*, I. CASTRO-ROMERO, P. MERCADO, S. HERNÁNDEZMARTÍNEZ, V. SERRANO-PINTO, M. RODRÍGUEZ, J. MARTÍNEZ-BARTNECHE and M.H.
RODRÍGUEZ, Instituto Nacional de Salud Pública, México.
Malaria remains the main parasitological disease in tropical areas around the world. Its control relies
heavily on the abatement of free parasite transmission by controlling the anppheline vectors, but their
increasing resistance to insecticides adds difficulties to stopping transmission. This disease is caused by a
protozoan parasite of the genus Plasmodium and is transmitted by mosquitoes of the genus Anopheles. An
essential step towards the development of new molecular approaches to fight malaria is a thorough
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understanding of the parasite’s interaction with mosquito defense responses. Our main purpose is to
understand the immune response in An. albimanus and its role in the transmission of Plasmodium. We
used a high throughput approach to identify An. albimanus immune proteins and peptides against
Plasmodium berghei in two main tissues that respond to parasitic invasion: the hemolymph and the
carcass (containing mainly the fat body). Carcass proteins were separated using 2 D gels and identified
by MALDI-TOF. The analysis of the carcass showed 10 differential proteins that appear only in mosquitoes fed with Plasmodium-infected blood. Interesting proteins, such as wingless, cytochrome P 450 and a
protein that probably participates in the protein ubiquitination, were identified. The protein wingless is
very important in morphogenesis and also in the immune response of Drosophila, but its function has not
been reported in mosquitoes. The cytochrome P450 has diverse functions and participates mainly in
xenobiotics elimination. Hemolymph peptides were analyzed by RP-HPLC and MALDI-TOF. In the
hemolymph of mosquitoes fed infected blood a peptide of 861 I/m with homology to Manduca sexta
protease H15 and an antibacterial peptide cecropin C3 were identified. Functional studies of the proteins
and peptides already identified currently are in progress to determine their role in malaria parasite
elimination
157
Wide-scale Analysis of Toxoplasma Invasion Protein Processing. V. LAGAL, E. BINDER, Departments of
Medicine and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx NY, R. DIAZ,
D. CHEN, M. GUCEK, R. COLE, Mass Spectrometry/Proteomics Facility, Johns Hopkins School of
Medicine, Baltimore MD, K. KIM, Departments of Medicine and Microbiology and Immunology, Albert
Einstein College of Medicine, Bronx NY and V. CARRUTHERS*, Department of Microbiology &
Immunology, University of Michigan, Ann Arbor MI, USA.
Like other apicomplexans, Toxoplasma gondii is an obligate intracellular parasite that relies critically on
active cell invasion to access the protective and fertile interior of a target host cell. Although it has been
known for several years that the activity of a parasite enzyme called microneme protein proteases 2
(MPP2) is responsible for trimming proteins involved in cell and tissue invasion, the identity of this
protease remained unknown. Trimming of invasion proteins occurs only upon secretion and is sensitive
to the protease inhibitors ALLN and chymostatin, suggesting that MPP2 is a secreted cysteine or serine
protease. Proteomic analysis by differential gel electrophoresis (DIGE) showed a limited number of
ALLN-sensitive substrates among the secreted material, including the invasion protein complex MIC2–
M2AP, MIC4, and the subtilisin-like serine protease, SUB1. Since SUB1 is the most abundant secreted
protease, we created a knockout strain deficient in SUB1 to test whether it is involved in the processing
of invasion proteins. Strikingly, DIGE analysis of secreted material from SUB1 knockout parasites almost
perfectly mirrored that of ALLN-treated parasites. No MPP2 processing of MIC2–M2AP or MIC4 was
observed in the knockout, and these defects were reversed upon re-expression of SUB1. SUB1 is normally GPI anchored. Interestingly, genetic complementation with a non-anchored mutant failed to
restore MPP2 processing, suggesting that trimming occurs on the parasite surface and not after release
into the culture supernatant. We conclude that SUB1 most likely is MPP2 and currently, we are assessing
the effects of SUB1 loss of function on Toxoplasma infection.
158
Mast Cells Play an Important Role in the Innate Immune Response Against Trichinella spiralis. N.
ARIZMENDI-PUGA, UIMEIP-Pediatría, Centro Médico Nacional Siglo XXI, IMSS, México DF, México,
J.A. ENCISO-MORENO, UIMS-Zacatecas, IMSS, México, D. BEFUS, Pulmonary Research Group,
Department of Medicine, and Department of Physiology, University of Alberta, Edmonton, Alberta,
Canada, G.M. ORTEGA-PIERRES, Departamento de Genética y Biología Molecular, CINVESTAV,
México DF, México, and L. YÉPEZ-MULIA*, UIMEIP-Pediatría, Centro Médico Nacional Siglo XXI,
IMSS, México DF, México.
Mast Cells (MC) play an important role in the expulsion of T. spiralis adult worms from the intestine of
infected animals. This process can be induced by T. spiralis muscle larvae, and IL-4 and TNFα, participate
both in the parasite expulsion and in the enteropathy observed in the infected host. Our group has
focused on the study of the participation of specific antigens from T. spiralis muscle larvae (TSL-1) in the
induction of innate immune response in the host through the activation of MC by an independent IgE
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pathway and the release of specific mediators. We demonstrated that direct activation of unsensitized
normal MC by TSL-1 antigens induces histamine, IL-4 and TNF release. Interestingly, in these studies,
no β-hexosaminidase release was detected from these cells when stimulated with TSL-1 antigens, suggesting that histamine and β-hexosaminidase are released in a highly selective and differential manner.
Further studies showed that histamine secretion by MC activated with TSL-1 shares some features with
substance P induced histamine secretion; however, it is Ca2+ independent. These results suggest that MC
stimulated by TSL-1 could be a source for IL-4 and TNFα, providing important evidence on the role of
MC secreted regulatory molecules in the induction of a Th2 type immune response during intestinal
infections by T. spiralis.These observations indicate that MC are important in the host innate immunity
to T. spiralis.
159
Innate Immunity in Invertebrates: Is Pattern Recognition Enough? E.S. LOKER, Department of Biology,
The University of New Mexico, Albuquerque NM, USA.
The completion of invertebrate genome sequences and the application of a broad array of molecular tools
to the study of model organisms like Caenorhabditis elegans and Drosophila melanogaster have given us
dramatic new means to view the internal defense capabilities of invertebrates. This is relevant to parasitologists both because invertebrates often serve as vectors and intermediate hosts of parasites and because
many parasites themselves are invertebrates and have to contend with their own pathogens. The power
of genetic tools for model invertebrates also has lead directly to fundamental new insights into the
workings of innate immunity in vertebrates. Principally because of the parallel structure of fly and
mammalian receptor and cell signaling pathways, there has been a tendency to homogenize our view of
innate immune responses across phyla, and to assume innate immune recognition depends to a large
extent on the presence of receptors that recognize invariant molecular patterns associated with major
groups of pathogens. However, given the extraordinary diversity of invertebrate phyla, and that many
invertebrates live for decades in environments laden with potentially fast-evolving pathogens, can reliance
on relatively invariant pattern recognition really be enough to protect them? Emerging results from
several invertebrate models have pointed to the discovery of means to diversify molecules believed to be
of relevance to internal defense, suggesting that innate immunity may not be as limiting as it might
seem. Some of these discoveries will be reviewed and their implications for future studies of innate
immunity in invertebrates discussed. (Supported by NIH RO1 AI24340.)
160
Impaired Innate Pro-inflammatory Response and Resistance to Toxoplasma gondii Infection in Mice
Lacking Macrophage Migration Inhibitory Factor. M. RODRÍGUEZ-SOSA*, M. REYES, Unidad de
Biomedicina, FES-Iztacala, UNAM, R. SAAVEDRA, Depto Inmunologia, IIB, UNAM, A.R. SATOSKAR,
Department of Microbiology, The Ohio State University, Columbus OH, USA, and L.I. TERRAZASVALDÉS, Unidad de Biomedicina, FES-Iztacala, UNAM, México.
Macrophage-migration inhibitory factor (MIF) is a pro-inflammatory cytokine that is involved in the
host defense against several pathogens. Here, we used MIF-/- BALB/c mice to determine the role of
endogenous MIF in the regulation of host immune response against Toxoplasma gondii infection. Following i.p. infection with tachyzoites of the virulent RH strain, MIF-/- mice developed severe clinical signs
of sickness and succumbed to T. gondii infection faster than MIF+/+ mice. In contrast, following
infection with the avirulent strain Me49 of T. gondii WT mice showed no mortality, whereas close to
95% of MIF-/- mice succumbed by day 40 after infection. Enhanced susceptibility of MIF-/- mice to T.
gondii was associated with reduced levels of pro-inflammatory cytokines such as TNF-α, IL-18, IFN-γ
and IL-1β in their sera. Along the infection, MIF+/+ and MIF-/- mice produced comparable levels of
IL-10, IL-4, antigen specific IgG1 and IgG2a. Assays using dendritic cells (DCs) ex-vivo as well as
maturated in vitro, showed that MIF-/- mice have a similar percentage of DCs, but with significantly less
ability to produce TNF-α and IL-12 in response to Toxoplasma soluble antigen stimulation. Lastly, brains
from T. gondii-infected MIF-/- mice displayed increased number of parasite cysts, as early as 10 days after
infection, when compared to MIF+/+ mice. Taken together, our findings show that MIF plays a critical
role in the early pro-inflammatory response that is necessary to control acute Toxoplasmosis. (Work
supported by DGAPA-UNAM Grant IN208606, CONACYT J-49911 and PAPCA FES-Iztacala.)
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161
Helminths Induce T Regulatory Cell Circuits and Modulate Mucosal Inflammation. J.V. WEINSTOCK,
Tufts University, Boston MA, USA.
Inflammatory bowel disease (IBD) and other immune-mediated illnesses are common in industrialized
countries, but are rare in tropical less-developed countries. Immune-mediated diseases emerge as countries develop. Among the many changes that come with socio-economic improvement is a loss of
exposure to helminths. It is possible that exposure to helminths inhibits IBD and the development of
other immune-related diseases. We find that mice harboring helminths are protected from developing
colonic inflammation. Previously established colonic inflammation resolves in mice that are exposed to
helminths. In clinical trials, patients with IBD improve when given viable embryonated Trichuris suis ova.
Helminths alter host immune responses in several ways that can inhibit IBD. Lamina propria mononuclear cells (LPMC) isolated from mice with helminths make less IL12p40 and IFNg, but more IL10
and TGFb than LPMC from worm-free mice. Colonization with Heligmosomoides polygyrus increases
Foxp3 expression by mesenteric lymph node (MLN) and LP T cells. Transfer of MLN T cells from
colonized mice to colitic mice ameliorates inflammation. Colonization induces a LP Tlr4+ T cell population that produces TGFb in response to LPS. Colonization also induce a LP CD8+ regulatory T cell that
can inhibit antigen-induced T cell proliferation and prevent colitis in an IBD animal model. Thus,
helminths increase T regulatory activity that may protect from immune-mediated diseases such as IBD.
162
The Mosquito’s Anti-Plasmodium Immune Defense. G. DIMOPOULOS, Molecular Microbiology and
Immunology, Johns Hopkins School of Public Health, Baltimore MD, USA.
Transmission of malaria requires successful completion of complex interactions between the Anopheles
vector and the Plasmodium parasite. These interactions involve mosquito immune and other physiological
responses to the invading ookinetes and other components of infected blood, and accurate execution of
Plasmodium’s gene expression program that directs its developmental transitions and interactions with
the vector. Major obstacles are encountered in the midgut tissue, where most parasites are killed by the
mosquito’s immune system. A comparative analysis of A. gambiae transcript responses to midgut invasion of P. berghei and P. falciparum ookinetes showed broad variations and have identified factors that can
modulate infection levels of both or only one of the two parasite species. Invasion by P. berghei had a
more profound impact on the mosquito transcriptome, including a variety of functional gene classes,
while P. falciparum elicited a broader immune response at the gene transcript level. Ingestion of human
malaria-infected blood lacking invasive ookinetes also induced a variety of immune genes, including
several anti-Plasmodium factors. The mosquito is capable of sensing infected blood constituents in the
absence of invading ookinetes, thereby inducing anti-Plasmodium immune responses. Seven of the 12
functionally tested genes were found to influence mosquito resistance to both parasite species. While all
genes that affected Plasmodium development also influenced mosquito resistance to bacterial infection,
four of the antimicrobial genes had no effect on Plasmodium development. The defense against the two
Plasmodium species is mediated by immune factors with both universal and Plasmodium-species specific
activities. The bacterial exposure plays a major role in priming the mosquito’s anti-Plasmodium defense.
163
Vector–Plasmodium Interactions: Plasmodium vivax Development in the Main Malaria Vectors in
México. M.H. RODRÍGUEZ*, L. GONZÁLEZ-CERÓN, M. RODRÍGUEZ, J.A. NETTEL-CRUZ and J.E.
HERNÁNDEZ-AVILA, Instituto Nacional de Salud Pública, México.
An. albimanus and An. pseudopunctipennis are the principal malaria vectors in México; these mosquito
species are widely distributed in the Mexican territory. P. vivax produces more than 99% of malaria cases
in this country, and the two P. vivax phenotypes (VK210 and VK247) have been identified. A comparison of the mosquito susceptibilities using insectary reared An. albimanus and An. pseudopunctipennis, fed
simultaneously with P. vivax infected blood obtained from patients, indicate that these two species have
different susceptibilities to both phenotypes. In An. albimanus high VK210 oocyst densities developed
while few or none VK247 oocyst did. The opposite was observed in An. pseudopunctipennis. The susceptibilities of An. pseudopunctipennis colonies from areas separated by 2,000 km, Tapachula in the south and
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Abasolo in the north were similar suggesting that susceptibilities of An. pseudopunctipennis to the P.
vivax phenotypes are similar in the whole country. VK210 y VK247 ookinete development in the blood
meal bolus differs bin time and synchronization, and the possible participation of receptor molecules on
the internal surface of the epithelial midgut determines the susceptibility-resistance in both mosquito
species. VK210 parasite, of show development are destroyed by midgut digestive enzymes that are early
produced in An. pseudopunctipennis, while VK247 parasites of rapid development invade the midgut
epithelium of this mosquito before they could be damaged by the digestive enzymes. VK210 parasites
can survive in An.albimanus, because their aminopeptidases are of show release. This parasites invade the
epithelium of these mosquitoes by the recognition of calreticulin, while VK247 parasites are halted at
this level and later destroyed by digestive enzymes.
164
Innate Immunity in Mosquito Vectors: Cells, Melanin and Immune Peptides. B.M. CHRISTENSEN,
Department of Pathobiological Sciences, University of Wisconsin, Madison WI, USA.
The mosquito innate immune response is a major factor governing the interaction between vector and
pathogen; consequently, it is a primary determinant of vector competence. Innate immunity in insects
employs both cellular and humoral components in response to invading pathogens, but studies of the
humoral aspects of innate immunity have dominated, with a primary emphasis on the identification of
antimicrobial peptides (AMPs) and the signaling pathways involved in their production. Far less emphasis has been placed on hemocytes and cellular immune responses, but data clearly verify that cellular
responses play a critical role in clearing pathogens by phagocytosis, encapsulation and/or melanization.
There is a void in the data required to accurately define regulatory processes, hemocyte-produced effector
molecules, and the role these cells and cell products play in innate immunity. In addition, it is not known
how cellular and AMP-based humoral responses function in concert to clear infections. It now seems
evident that a reductionist approach that studies one gene, or a small set of genes, in relation to a phenotype has limitation for determining the complex interrelationships that undoubtedly exist in mosquito
innate immune responses. Our general hypothesis is that these responses are a highly complex network of
processes that employ several distinct, but not mutually exclusive, humoral and cellular responses to clear
pathogens from the hemolymph. We have been testing this hypothesis with two culicine mosquitoes and
a number of infectious agents in high-throughput molecular approaches to profile gene transcription and
to identify distinct patterns underlying innate immune responses. Results from microarray analyses were
further analyzed using RNAi methodologies, synthetic peptides and phenotype evaluations to better
define the interaction of various genes and gene products. The best summary I can provide of our
findings to date is that we now realize we really do not know very much about innate immunity in these
insects.
165
Suitability Environmental Model for the Geographic Distribution of Malaria Vector Mosquitoes in
México. J.E. HERNÁNDEZ-AVILA*, M.H. RODRÍGUEZ and R. SANTOS, Instituto Nacional de Salud
Pública, México.
Malaria is a permanent public health problem in México; the main vectors in the country are An. albimanus and An. Pseudopunctipennis and their geographic distribution is linked directly to the risk of
malaria infection in the population. The size of the country makes it very hard to collect specimens so it
is necessary to develop models to predict or at least identify the most suitable conditions for the vector
mosquitoes to breed and survive. Objective: to develop a suitability model for the geographic distribution of malaria mosquito vectors in México. Material and Methods: environmental and climatic information of the entire country was incorporated into a geographic information systems (GIS), all historical
data about mosquito collections was geo-referenced and also incorporated into the GIS. New layer were
constructed in the GIS based frequency of collection by each level of the environmental/climatic variables
to form a suitability index for each variable, these layers were spatially added up to create a composite
suitability index. Results: maps of the distribution of suitable environmental and climatic conditions for
the presence of An. albimanus and An. Pseudopunctipennis were developed, there is a strong spatial
correlation with the distribution of historical malaria cases.
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166
Mechanism of Virulence of Entamoeba histolytica. R. PÉREZ-TAMAYO*, A. OLIVOS, E. RAMOS, M.
NEQUIZ, Departamento Medicina Experimental, Facultad de Medicina, UNAM, M. EL HAFIDI,
Departamento Bioquímica, Instituto Nacional de Cardiología, A. SARALEGUI, Unidad de Microscopía
Confocal IBT, UNAM, E. TELLO, R. LÓPEZ and I. MONTFORT, Departamento Medicina Experimental,
Facultad de Medicina, UNAM, México.
Entamoeba histolytica is the protozoan parasite responsible for human amebiasis and causes approximately
100,000 deaths each year worldwide. Parasite virulence has been attributed to many molecules, such as
adhesins, amebopores and cystein proteinases, but evidence supporting such views is either partial or
indirect. In this work, we compared virulent E. histolytica (vEh) (achieved through continuous liver
passages in hamsters) with non-virulent E. histolytica (nvEh) (achieved through continuous in vitro
cultures) in some of their functions, such as: complement resistance, cysteine and aspartic proteinase
activities, hemolytic, phagocytic and cytotoxic capacities, transepithelial electrical resistance and oxygen
susceptibility. We found that the only strong difference was a marked susceptibility to oxygen in nvEh.
Next we explored the molecular mechanism of this difference. We analyzed superoxide and hydrogen
peroxide molecules in both groups of amebas after high oxygen exposure. We found more superoxide
production in vEh, whereas the highest hydrogen peroxide concentration was observed in nvEh. On the
other hand, dihidroethydium, a specific superoxide scavenger, was capable of increasing the nvEh oxygen
resistance to levels comparable to vEh. Taken together, our results suggest for the first time that of all the
amebic functions analyzed, only oxygen resistance is correlated with virulence. Finally, the molecular
explanation of oxygen susceptibility in nvEh could be due to differences in: unknown superoxide producer, FeSOD, NADPH flavin-oxide-reductase and/or amebic peroxirredoxin activities, or in non
enzymatic molecules. Currently, these possibilities are being pursued in our laboratory. (Supported by
grant PAPIIT IN205407 from UNAM.)
167
The Cryptosporidium Volunteer Study: Bridges over Troubled Waters. C.L. CHAPPELL*, Center for
Infectious Diseases, The University of Texas School of Public Health, Houston TX, P.C. OKHUYSEN,
Division of Infectious Diseases, The University of Texas School of Medicine, Houston TX, and C.
WHITE, Division of Infectious Diseases, Baylor College of Medicine, Houston TX, USA.
Cryptosporidium causes outbreaks of waterborne diarrheal illness in communities. To better understand its
infectivity and disease outcomes, healthy adult volunteers were studied. After informed consent, healthy
volunteers were fed a known number of Cryptosporidium oocysts and monitored for six weeks. The data
presented represent the collective experience from 186 volunteers. Infectivity was established for C.
parvum and C. hominis isolates by generating dose–response curves in antibody-negative individuals. ID50
of isolates varied from 10–1000 oocysts. Parallel studies were done with two C. parvum isolates in
persons with pre-existing anti-Cryptosporidium IgG. ID50’s increased 14–20 fold, and protection from
infection and illness was seen at low dosages. In addition, infectivity of C. muris and C. meleagridis in
healthy subjects was established using a single, large oocyst dose. All volunteers shed oocysts, and some
developed diarrhea characteristic of C. parvum and C. hominis infection. Unlike the other Cryptosporidium
species, C. muris persisted for months in some persons as an asymptomatic infection. Studies in antibody-negative individuals indicate that: asymptomatic infections occur; symptoms range from mild GI
complaints to profuse diarrhea; illness outcomes vary with isolate, but not species; and the illness attack
rate is independent of ID50. Illness in volunteers with pre-existing serum IgG occurred only at high
oocyst dosages and was more severe than in the antibody-negative persons. In all volunteers, enteroscopic biopsies revealed little mucosal damage, but significant changes in mucosal lymphocyte populations were seen in infected versus uninfected subjects. Certain cytokines, such as interferon g, was
associated with control of the infection. Volunteer studies have added significant knowledge regarding
Cryptosporidium infectivity and illness and contributed key data for risk assessment modeling of waterborne transmission.
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168
Water-borne, Free-living Amebae as Agents of CNS Infections. F.M. MARCIANO-CABRAL* and G.A.
CABRAL, Department of Microbiology and Immunology, Virginia Commonwealth University School of
Medicine, Richmond VA, USA.
Naegleria fowleri and several species of Acanthamoeba are free-living amebae that are ubiquitous and
found in a variety of fresh-water habitats. In nature, the amebae feed on bacteria and yeast. Under
conditions yet to be defined, however, they can cause infections in humans and animals. Several species
of Naegleria have been isolated and described, but only N. fowleri has been associated with human
disease. N. fowleri is the causative agent of Primary Amebic Meningoencephalitis (PAM), a rapidly fatal
disease of the central nervous system (CNS) that is generally acquired while swimming and diving in
freshwater lakes, ponds, and in recreational water areas such as spas and improperly chlorinated swimming pools. N. fowleri has been identified also in domestic water supplies in the United States and
Australia. Sensitive and specific PCR assays have been developed to identify these amebae in water and
human tissue. Acanthamoeba spp. are the causative agents of Granulomatous Amebic Encephalitis
(GAE), a chronic infection of the CNS, and of cutaneous lesions in immune-suppressed patients.
Acanthamoeba also can cause amebic keratitis, a painful, eyesight-threatening disease in immune-competent individuals. An increase in the number of cases of PAM and GAE has been reported in recent years.
This increase may be due, in part, to thermal pollution of water from cooling towers of nuclear power
plants that may serve to promote the growth of amebae and the bacteria that serve as their food source.
Furthermore, recent reports indicate that the amebae may serve as “reservoirs” for bacteria with pathogenic potential. Thus, with the increase in the number of individuals who are immune suppressed due to
organ transplantation, cancer chemotherapy, immune deficiency virus (HIV) infection, and use of illicit
drugs, a higher incidence of CNS infections with free-living amebae may be anticipated. (Supported in
part by National Institutes of Health awards DA05274 and DA05832.)
169
Differentiation of Giardia lamblia: New Structural Insights. A. MARTÍNEZ-PALOMO* and B. CHÁVEZMUNGUÍA, CINVESTAV, México DF, México.
The high prevalence of giardiasis worldwide depends to a great extent on the striking sturdiness of G.
lamblia cysts. While G. lamblia has been the subject of recent studies concerning the biology of the
trophozoite stage, the mechanisms involved in the resistance of the parasite cysts to adverse environmental conditions are not known. In their cystic phase, giardias are protected from the environment by a
filamentous cyst wall made up of carbohydrates, proteins, and by two outer membranes separated from
the plasma membrane of the parasite by a peripheral space. We have used high resolution transmission
electron microscopy to detail the morphology and development of the complex outer membranous
system of encysting, mature, and existing cysts of G. lamblia. Our observations have demonstrated that
the extracellular peritrophic space originates from the growth, elongation, and fusion of large cytoplasmic vacuoles. As the large clear vacuoles grew in size, flattening against the inner face of the plasma
membrane, they formed a single vacuole that surrounded the body of the parasite, eventually forming
two outer membranes. In mature Giardia cyst, the original plasma membrane of the trophozoite becomes the outermost membrane of the cyst wall (CM1). The large vacuoles form a second membrane
surrounding the cyst (CM2), and also form a third membrane (CM3), that becomes the new plasma
membrane of the trophozoite. During excystation CM1 and CM2 attach to each other and fragment,
leaving abundant membrane residues in the peritrophic space. Knowledge of the biochemical composition and functional properties of the complex outer membranous system of G. lamblia cysts here described will be of use to understand the survival of giardia cysts in the environment.
170
Unique Parasitic Specialisations Across the México–USA Border. R.C. TINSLEY, School of Biological
Sciences, University of Bristol, Bristol, U.K.
The foundations of parasitological knowledge established by researchers in México and the USA contain
many indications of evolutionary innovations unique among parasitic adaptations. Taxonomic descriptions may provide a hint to exceptional life-history characteristics and to experimental studies needed to
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elucidate mechanisms. This review highlights the pioneering contributions made by Rafael LamotheArgumedo in México and Robert Kuntz and others in the USA in providing a basis for experimental
research and illustrates findings revealed by subsequent investigations. The monogenean Pseudodiplorchis
americanus infects desert toads, Scaphiopus couchii, on both sides of the U.S./México border and has
reproductive specialisations without precedent anywhere among platyhelminths. These include unique
mechanisms for nutrition of embryos within the parental uterus, maintaining infective stages in instant
readiness for once-a-year opportunities for transmission. In Polystomoidella oblonga, larvae hatch and
achieve advanced development within the parent (first recorded 40 years ago by Oglesby in the USA). In
Polystoma nearcticum (described 70 years ago by Paul), reproduction is targeted precisely into brief
periods of host availability: egg output is controlled by host sexual excitement. Egg production rates by
Polystomoides spp. are exceptionally low (one egg/worm/day) suggesting undiscovered adaptations for
effective host invasion. Further research insight is provided by an African monogenean established along
the California/México border in feral populations of its introduced host, Xenopus laevis: Protopolystoma
xenopodis demonstrates the effectiveness of regulation of natural parasite populations by a powerful host
immune response. The ‘classical’ (older!) literature is a rich repository of clues that may direct modern
parasitological research toward applications of wider significance. The results emphasise the research
potential of investigations combining fieldwork and laboratory experimentation.
171
Helminth Parasites of Freshwater Fishes in México: Uncovering Patterns of Species Richness. G. PÉREZPONCE DE LEÓN, Departamento de Zoología, Instituto de Biología, UNAM, México DF, México.
Evolutionary processes and historical biogeographical events are the main forces determining the way in
which parasite species (within any given taxon) are distributed among host species or among geographical areas. These distribution patterns provide information to discriminate which force has played the
most important role in shaping the host–parasite association. I have made use of the database of helminth parasites of freshwater fishes of México to uncover and describe general patterns of species richness.
I focus on two components of parasite diversity: species richness and species composition. México
represents the boundary between the Nearctic and Neotropical biogeographical regions (a transitional
zone). Freshwater fish fauna is diverse (with very high levels of endemism), resulting from a complex
geological history. About 384 species have been described. Studies on the helminth parasite fauna of
freshwater fishes in México began in 1936 (Manter, Yucatán Peninsula), but most of the inventory we
have gathered thus far was obtained from survey work undertaken during the past 15 years. The inventory is far from complete yet, but almost 60% of the freshwater fishes have been examined, to a certain
extent, for helminths (if only freshwater environments are considered). Thus far, about 150 species of
adult helminths have been recorded. Empirical data clearly shows that the helminth parasite diversity in
Mexican freshwater fishes is determined by the historical and contemporary biogeography of their hosts,
so their distributional patterns follow that of their hosts, while the host association patterns are largely
determined by some degree of host specificity, with the adult parasite fauna being largely circumscribed
by higher levels of monophyletic host taxa. New information derived from DNA markers (nuclear and
mitochondrial), in conjunction with morphological data, have become crucial for the establishment of
species limits and the understanding of parasite diversity in freshwater fishes, since our data reveal that
instances of cryptic speciation are ocurring, and this is relevant to discuss evolutionary processes and
historical biogeographical events.
172
Social Rank and Parasitism in Japanese Macaques. A.D. HERNÁNDEZ* and M.A. HUFFMAN, Primate
Research Institute, Ecology Section, Kyoto University, Inuyama, Aichi, Japan.
Parasites are often aggregated within host populations, with a few host individuals harboring the majority of the parasite population. In primates, these distributions are thought to be host dependent. For
example, host social status is predicted to be an important factor that can influence whether the encounter between parasites and hosts is favorable or unfavorable. Relatively few studies, however, have examined the relationship between social rank and parasitism. We describe an ongoing study on metazoan
parasites infecting a Japanese macaque subspecies, Macaca fuscata yakui, endemic to Yakushima Island
(Japan). A matrilineal hierarchy exists in Japanese macaques, and within troops there also are ranked
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female kin-groups, or groups with stronger family ties compared to other members of the troop. Adult
males are always dominant over females, but are only tenured in a troop for approximately three years.
This study records behaviors within a 30-day period every other month of 13 adult female and three
adult male individuals in “Umi” troop, and collects their feces bimonthly for helminth eggs. Agonistic
bouts between two individuals are noted, and social rank of focal animals then is determined using a
dominance hierarchy matrix. The objective of this study is to correlate prevalence and relative eggs per
gram of feces for five nematode parasites known to infect macaques on Yakushima, Oesophagostomum
aculeatum, Strongyloides fuelleborni, Trichuris trichiura, Streptopharagus pigmentatus and Gongylonema spp.,
to absolute social ranks and relative rank groups. Only one previous study has examined the relation
between social rank and parasite load in a primate species, olive baboons, and the data suggested there
was no relationship between social rank and parasitism. Data from the current study will provide more
robust inferences on the relationship between social rank and parasitism in primates, and about our
understanding of the importance of host-dependent factors on the aggregated distribution of parasites.
173
Epidemiology and Chronobiology of Schistosomes from Lake Victoria, Kenya. M.L. STEINAUER*,
Department of Biology, The University of New Mexico, Albuquerque NM, USA, I.N. MWANGI, J.M.
KINUTHIA, G.M. MAINA, G.M. MKOJI, Centre for Biotechnology Research and Development, Kenya
Medical Research Institute, Nairobi, Kenya, and E.S. LOKER, Department of Biology, The University of
New Mexico, Albuquerque NM, USA.
Several species of schistosomes inhabit the Lake Victoria basin, including two species that infect snails of
the genus Biomphalaria: Schistosoma mansoni, typically a parasite of humans, and Schistosoma rodhaini,
typically a parasite of rodents. A study was undertaken to examine prevalence and abundance of these
species within their snail hosts in the Kenyan portion of the lake and to examine their chronobiology or
circadian patterns of the emergence of cercariae. Over two years, snails were collected from in and
around Lake Victoria and examined for schistosome infection. Infected snails were monitored for 24
hours, and the number of cercariae released each hour was enumerated. Cercariae released during four
time intervals were pooled and used to infect mice, and the specific identity of the resulting adults was
determined using PCR amplification and sequencing of the 16S region of DNA. Also, 20 microsatellite
loci were genotyped to determine the number of genotypes that inhabited each snail. Shedding profiles
were replicated for each snail every week for five weeks or until the snail died. A total of 131 infected
snails were collected that contained 131 genotypes of S. mansoni and 15 genotypes of S. rodhaini. Multiple infections were rare and only eight snails contained two genotypes of S. mansoni, one snail contained three, and one snail contained four, of which three were S. rodhaini and one was S. mansoni. A
total of 335 circadian profiles from 138 snails have revealed that the timing of cercarial emergence of S.
rodhaini from Kenya differs from previous reports of a single nocturnal peak. In Kenya, S. rodhaini
emerges throughout the 24-hour cycle, but especially in the early morning between 3 and 5 a.m, and
some individuals also show a nocturnal as well as a diurnal peak. The peak of emergence for S. mansoni
occurs between 9 a.m. and 12 p.m, which is similar to, but earlier than other populations that peak at 12
p.m. Emergence of these two species overlaps temporally and allows the possibility for a host to become
infected with both species, which could result in hybridization.
174
Food Webs and Seasonal Dynamics of an Amphibian Parasite Community: Do Bottom-up Effects Drive
Infection? T.R. RAFFEL*, R.S. HUANG, Biology Department, Pennsylvania State University, University
Park PA, J.M. KIESECKER, The Nature Conservancy, Wyoming Chapter, Lander WY, and P.J. HUDSON,
Biology Department, Pennsylvania State University, University Park PA, USA.
Seasonality is a dominant force in ecological systems, but has been largely ignored in studies of amphibian parasites, despite the apparent seasonality of parasites implicated in amphibian declines. To identify
potential drivers of seasonal parasite dynamics in amphibians, we undertook a seasonal survey of four
populations of red-spotted newts (Notophthalmus viridescens), tracking seasonal patterns in the parasite
community and associated environmental and immunological factors. We also conducted a meta-analysis
seeking general patterns in the seasonal dynamics of newt parasites. Most red-spotted newt parasites
increased in abundance in the spring and early summer, but no single factor could account for this
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general pattern of high spring infection rates. Intermediate host abundance and environmental temperature were most often found to be significant predictors of parasite dynamics, but negative effects of host
density, seasonal changes in host immunity, interactions with other parasites, and densities of alternate
hosts also appear to play important roles. These results can be best understood in the context of food
web dynamics, whereby generally high spring infection rates are driven indirectly by common bottom-up
effects of high spring productivity on the multiple factors driving parasite exposure. Since climatic
warming is likely to influence patterns of primary productivity in ponds, our findings support the
hypothesis that climate disruption will influence amphibian parasite dynamics.
175
Escaping the Poop Cocoon: Are There Behavioral Adaptations of Toad Tapeworms for Transmission?
M.G. BOLEK* and J. JANOVY, JR., School of Biological Sciences, University of Nebraska, Lincoln NE,
USA.
Distoichometra bufonis is a nematotaeniid tapeworm that predominantly infects terrestrial toads in North
America. Previous population studies on this tapeworm in Woodhouse’s toad, Bufo woodhousii, in western
Nebraska indicate that it uses an intermediate host in its life cycle. However, the intermediate host is
unknown. In order to understand the potential transmission route(s) of this tapeworm to its toad
definitive host, we examined (1) the abiotic conditions affecting proglottids, (2) behavior of gravid
proglottids of D. bufonis shed by toads, (3) visitation of potential arthropod intermediate hosts to toad
feces containing gravid proglottids, and (3) the diet of Woodhouse’s toads. Our results indicate that (1)
during July, toad feces reaches an average daily temperature of 46°C, and become a dry solid mass that
persisted in the environment for up to four weeks, (2) gravid proglottids of D. bufonis moved to the
surface of toad feces, contracted and began releasing eggs within minutes of toad defecation, (3) the
most common invertebrates visiting toad feces were ants of two genera (Dorymyrmex sp. and Pheidole
sp.), and (4) Woodhouse’s toads were considered active foragers predominantly feeding on ants, flies,
and beetles. We hypothesize that gravid proglottids of D. bufonis migrate to the surface of toad feces,
thus making worm eggs available to the intermediate host(s) in a terrestrial environment, and ants may
be good candidates for intermediate hosts infection studies.
176
Parasites of the Fiddler Crab Uca thayeri in Celestún, Yucatán, México. N. ARGÁEZ-GARCÍA*, L.
AGUIRRE-MACEDO, CINVESTAV-IPN, Unidad Mérida, Yucatán, and S. GUILLÉN-HERNÁNDEZ,
Departamento de Ecología, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma
de Yucatán, Mérida, Yucatán, México.
We analyzed the spatial–temporal distribution of the metazoan parasite communities of Uca Thayer in
the Celestún Lagoon, México. Celestún Lagoon is located at 20º45′N and 90º15′W, on the western
shore of the Yucatán Península, southeast of the Gulf of México, and is divided into three zones: the
inner zone, characterized by low salinity; the mouth zone, where the lagoon connects to the sea, with
high salinity; and the intermediate zone, with intermediate salinity. From July 2004 to August 2005, a
total of 278 “fiddler crabs” were analyzed monthly in four localities: Ya’xaá, Baldiocera, Puente and Boca.
Besides the crab samples, physiochemical data was obtained. Infection parameters for the parasite species
at each locality and season were obtained. Metazoan communities of U. thayeri were compared among
localities at two levels: Infracommunity and Component Community. Four parasite species were found:
Probolocoryphe sp., Nematoda gen. sp., Hexaglandula corynosoma and Leydia sp. Spatially, the higher
infection values were for the nematode in Ya’xaá, Baldiocera and Puente, and for Probolocoryphe sp. in
Boca. A spatial trend in the infection parameters of the parasite species was observed from freshwater
springs to marine water: Probolocoryphe sp. and H. corynosoma had a positive trend, and Leydia sp. and
Nematoda gen. sp. had a negative one. The communities were characterized by low values in all the
parameters. Infracommunity and component community in Ya’xaá and Baldiocera were dominated by
the nematode, while in Puente and Boca the dominant species was Probolocoryphe sp. The relative abundance of species in the communities of U. thayeri depends heavily on the environmental characteristics of
the sample site. Temporally, the higher values were for Probolocoryphe sp. and Nematoda gen. sp., in
nortes and dry, and the lowest values were for Leydia sp. all seasons. Infracommunity and component
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community in nortes and dry were dominated by the nematode and Probolocoryphe sp., while in the rainy,
the dominant species was Probolocoryphe sp.
177
Analysis of an ABCG Gene in Drug Sensitive and Resistant Lines of Plasmodium yoelii. I. FERRERRODRÍGUEZ*, B. GONZÁLEZ, J.A. GARCÍA, G. GONZÁLEZ, Department of Natural Sciences and
Mathematics, Inter-American University of Puerto Rico, Bayamón PR, J. VEGA and A.E. SERRANO,
Department of Microbiology and Medical Zoology, School of Medicine, University of Puerto Rico, San
Juan PR.
The problem of drug resistance in malaria is increasing worldwide. Different members of the ATPBinding Cassette (ABC) superfamily of transporter proteins are capable of conferring drug resistance to a
variety of chemotherapeutic agents in neoplastic cells and other organisms. One such group of transporters belongs to the ABCG subfamily, which is related to drug resistance to fungicides and neoplastic
cancer cells. Previously, we identified the Plasmodium yoelii ABCG homologue gene (pybcrp) in
PlasmoDB 5X coverage (Contig 56) and showed expression in intraerythrocytic stages of the parasite by
RT-PCR. Computed transmembrane topology predictions revealed that the gene contains an ABC and a
membrane spanning domain (MSD), typical of half transporters. Multiple sequence alignments revealed
amino acid conservation of the Walker A, glutamine loop, ABC signature, Walker B, and histidine loop
motifs. The ABCG homologue gene shares 92% and 63% identity at the amino acid level with the
homologue genes in P. berghei and P. falciparum, respectively. To ascertain if point mutations were present
in the drug-resistant lines of P. yoelii, the complete open reading frame of the gene was amplified by PCR
and sequenced in P. yoelii NS (chloroquine selected), NS/1100 (mefloquine selected) and ART (artemisinin selected) lines. Four amino acid substitutions were observed in NS/1100 and two in ART, as compared to the NS parental line. In addition, the 5r upstream region of the pybcrp gene was amplified by
PCR, cloned and sequenced, and no nucleotide changes were identified. Currently, we are performing
additional experiments to identify the transcription initiation site, gene copy number and expression
levels of the P. yoelii ABCG homologue.
178
Detection of Neospora caninum Antibodies in Milk in Korea. S. KANG*, Y. CHO, H. LEE, S. JUNG and
Y. JIN, Bacteriology and Parasitology, NVRQS, Anyang City, South Korea.
Neospora caninum (N. caninum) is a cyst-forming obligate intracellular protozoan parasite that was first
detected in Norwegian dogs, and was described and named in 1988. N. caninum is considered a major
cause of bovine abortion in several countries. Transplacental transmission of the parasite from an infected
cow to her foetus during pregnancy is the major confirmed method by which infection is maintained in
cattle herds. The presence of antibodies to N. caninum indicates that an animal is infected with the
parasite, and a number of assays for demonstration of specific antibodies have been developed. ELISA
could to be used to examine bovine milk for antibodies against N. caninum. To determine the agreement
between the serum ELISA–NVRQS and the milk ELISA–NVRQS results, Kappa statistics were performed as the value of 0.75 (means excellent agreement). of the 279 dairy cattle tested by the ELISA–
KNVRQS, 111 cattle (39.8%) were positive to N.caninum from 11 herds in several areas during 2006.
The distribution of antibody titers from the positive milk samples by ELISA–KNVRQS was shown, the
positive status from 1:2 to 1:64 of milk dilution mostly. But a milk sample come out the positive in
1:1,024 milk dilution unusually. Testing milk samples may have advantages over testing serum samples,
such as milk samples being easier to collect and thereby less expensive than sampling of serum. The
accidental transmission of diseases by needle and milk production losses due to stress can be reduced by
milk sampling because it is not harmful. We report here the result of ELISA for demonstration of
antibodies to N. caninum in milk and the possibility of using milk ELISA to assess the herd status of
infection of N. caninum.
179
In vitro Efficacy of Nitazoxanide Against Toxoplasma gondii. M. GALVÁN-RAMÍREZ*, J.A. GALVAN
VEGA, L.R. RODRÍGUEZ PÉREZ, M.A. RAMIREZ HERRERA and M.L. MENDOZA-MAGAÑA,
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Departamento de Fisiologia, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara,
Guadalajara, Jalisco, México.
Background: Nitazoxanide (NTZ 2-acetolyloxil-N-5-nitro-2-thiazoly benzamide) has been shown to
exhibit a wide spectrum of in vivo activity against a variety of intestinal parasites. The efficacy of NTZ
against the apicomplexan Cryptosporidium parvum has been published, however, there are no studies that
demonstrate its efficacy against Toxoplasma gondii. In toxoplasmosis, pyrimethamine (PYR) treatment is
associated with bone marrow toxicity, requiring supplemental administration of folic acid. Objective: The
aim of this study was to investigate the in vitro efficacy of nitazoxanide against Toxoplasma gondii using
different doses. Methods: Human fibroblasts were infected with Toxoplasma gondii and were treated with
5, 7 or 10 µg/ml of NTZ and PYR after 4 and 24 h. Treatments were evaluated six times in four replicas
and a control. Observations were performed using an inverted Olympus IX50 microscope with 45 X
magnification, and digital images were taken. Results: Preliminary assays were performed with 1 to 10
µg/ml doses of PYR or NTZ after 24 hours of infection. One hundred percent parasite mortality was
found with 8 µg/ml of NTZ. Viability after four hours of NTZ treatment, decreased in all doses compared to PYR effect, where viabilility was considerably greater. Viability comparison of NTZ against
PYR in 5 and 7 µg/ml doses was statistically significant (p < 0.0001). After 24 hours of treatment with
5, 7 or 10 µg/ml of NTZ, viability was lower than with PYR. Efficacy comparison between 5, 7 or 10
µg/ml of NTZ against PYR was statistically significant (p < 0.0001). When the efficacy of NTZ was
compared after 4 and 24 hours of treatment using 5 µg/ml, the difference was statistically significant (p
< 0.01) and for PYR using 7 µg/ml (p < 0.001). Conclusions: NTZ efficacy was higher than 90%,
viability of NTZ-treated Toxoplasma gondii tachyzoites with 7 and 10 µg/ml was less than 10%. The 10
µg/ml dose of NTZ produced a severe effect on the viability of Toxoplasma gondii tachyzoites.
180
Effect of Curcumin on G. lamblia Growth, Viability, Adhesion Capacity, Morphology, Apoptotic-like
Changes and Ion Currents. M.A. RAMIREZ-HERRERA*, M.L. MENDOZA-MAGAÑA, Depatamento de
Fisiología, CUCS, Universidad de Guadalajara, Guadalajara, Jalisco, R.A. NAVARRO-POLANCO, J.A.
SÁNCHEZ-CHAPULA, Centro Univ. de Inv. Biomédicas, Universidad de Colima, Colima, Colima, R.
CORTÉS-ZÁRATE, Departamento de Microbiología, CUCS, Universidad de Guadalajara, Guadalajara,
Jalisco, J. LARA-CHÁVEZ, Centro Univ. de Inv. Biomédicas, Universidad de Colima, Colima, Colima,
and L. PÉREZ-ARRIAGA, Depatamento de Fisiología, CUCS, Universidad de Guadalajara, Guadalajara,
Jalisco, México.
Giardia lamblia is one of the most important worldwide etiological causes of intestinal infections produced by protozoa. The search for new alternative therapeutic approaches for this parasitic disease is
important. Drugs used to control this infection frequently exhibit side effects that force patients to
abandon treatment. The present work evaluates the anti-giardial activity of curcumin, the main constituent of turmeric. G. lamblia (Portland 1 strain) cultures were exposed to different concentrations of
curcumin. We evaluated parasite growth, adhesion capacity, parasite morphology, induction of apoptosislike changes and alterations of total G. lamblia ion currents. All curcumin concentrations inhibited
trophozoite growth and adhesion in more than 50%, even at low concentrations and short exposure
times. Morphologically, protrusions formed under the cytoplasmic membrane, deformation due to
swelling and cell agglutination. Curcumin induced apoptosis-like nuclear staining, increasing in function
of concentration and exposure time. Ion currents in G. lamblia trophozoites were inhibited by curcumin
and the effect was reversed in at least 40% as the result of continuous washing. In conclusion, curcumin
exerted a cytotoxic effect in G. lamblia inhibiting parasite growth, adhesion capacity, inducing morphological alterations, provoking apoptosis-like changes and inhibiting total ion currents. In vitro and in vivo
experiments are endowed to elucidate the effect of curcumin in an experimental model of G. lamblia
infection and to analyze the involvement of ion channels in the swelling effect of curcumin during the
apparent osmotic disregulation in giardial trofozoites. The previous will lead to the proposal of the action
mechanism of curcumin and the description of the mechanism that activates the process for the apoptotic-like effect.
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181
Design and Synthesis of the Benzyl Ester of N-propyl Oxamate as a Possible Trypanocidal Pro-drug. C.
AGUIRRE-ALVARADO*, L. RODRÍGUEZ-PÁEZ, M.I. BAEZA-RAMÍREZ, Department of Biochemistry,
National School of Biological Sciences, National Polytechnical Institute, México, B. NOGUEDATORRES, Department of Parasitology, National School of Biological Sciences, National Polytechnical
Institute, México, and C. WONG-RAMÍREZ, Department of Biochemistry of the National School of
Biological Sciences, National Polytechnical Institute, México.
It has been demonstrated that selective inhibitors of T. cruzi alpha-hydroxyacid dehydrogenase isozyme
II (α-HADH) show trypanocidal activity. We found that N-propyl oxamate (NPOx) was an excellent
inhibitor of T. cruzi α-HADH; however, due to its polarity, this substance can not diffuse through the
hydrophobic membrane of T. cruzi to exert the expected trypanocidal effect. Therefore, we developed a
less polar substance, the benzyl ester of N-propyl oxamate (NPOx-B), as a possible pro-drug. The
NPOx-B was synthesized, characterized and evaluated on the activity of the purified T. cruzi α-HADH.
The results showed that this substance was not an inhibitor of this isozyme. On the contrary, in a homogenate of T. cruzi, where esterases also are present, the NPOx-B really inhibited T. cruzi α-HADH in a
similar way as NPOx inhibited this isozyme, indicating that NPOx is the true inhibitor of T. cruzi αHADH. We evaluated also the effect of NPOx-B on the viability of bloodstream trypomastigotes and on
cultured epimastigotes of NINOA and INC-5 T. cruzi strains. These experiments were run in comparison
with the trypanocidal effect produced by nifurtimox (Nf) and benznidazole (Bz), drugs commonly used
for the treatment of Chagas’ disease. The trypanocidal effect of NPOx-B on the bloodstream trypomastigotes of the NINOA and INC-5 strains was proportional to the concentration of this substance, producing 95–100% of death at 8 mM. The Bz had the lower trypanocidal effect among the three tested drugs
in both strains. Similar results were obtained with NPOx-B on epimastigotes of both strains, while Nf
and Bz showed lower trypanocidal effect in epimastigotes than in trypomastigotes of both strains. We
concluded that NPOx-B was more effective against circulating trypomastigotes and cultivated epimastigotes of NINOA and INC-5 strains than the employed reference drugs. Therefore, the NPOx-B can be
considered as a promissing pro-drug for the possible treatment of Chagas’ disease
182
Determination of Anthelmintic Drug Susceptibilities of Taenia crassiceps by a Fluorescent Label Assay.
D. GARCIA-VILCHIS*, J.R. AMBROSIO-HERNÁNDEZ, O.A. REYNOSO-DUCOING, Departamento de
Microbiologìa y Parasitologìa, Fac, R. CASTILLO, A. HERNÁNDEZ, F. HERNÁNDEZ, Departamento de
Farmacia, Facultad de Quìmica, Un, and L. YÉPEZ-MULIA, Unidad de Investigación Médica en
Enfermedades Inf., UNAM.
Albendazole, a benzimidazole derivative, has been used for treatment of cysticercosis due to Taenia
solium. Because of its poor biodisponibility and clinical evidence that indicates that this drug is not quite
effective during neurocysticercosis and taeniosis treatments, there are recommendations that the drug
needs to be combined with praziquantel, other anthelminthic drugs, or there is a necessity for producing
a new one. Because drugs based on benzimidazole derivatives (BZM) appear to have broad capability for
curing parasitic diseases, our multidisciplinary group considered it necessary to design, using new
strategies that included rational drug design and in vitro evaluation, new BZM compounds in order to
surpass the referred problems. Because in vitro evaluation of BZM in T. solium cystis is not easy, our
group has been using a murine model of cysticercosis known as Taenia crassiceps ORF strain cysticercosis
for evaluating potential cestocide activity of BZM; for this, we adapted a detection of a vital fluorescent
marker (CMFDA) that is activated by intracellular glutathione peroxidase system (GSH), an indicator of
metabolic machinery activation. Evaluation of metabolic changes in the activation of CMFDA permits us
to establish quantitatively the antiparasitic activity of BZM; the intensity of CMFDA fluorescence was
correlated with the effect of compounds on integrity of the cysts, and we are considering that this
method could be useful for determining in vitro anti-cysticerci activity of any potential drug for larval
stages of cestodes. (Work supported by CONACyT-Mèxico [43629] and DGAPA-UNAM [IN201003
and IN216107].)
134
ABSTRACTS
183
Apparent Emergence of Praziquantel Resistance in a Kenyan Isolate of Schistosoma mansoni. S.D.
MELMAN*, M.L. STEINAUER, E.S. HATTON, Department of Biology, The University of New Mexico,
Albuquerque NM, USA, G.M. MKOJI, Kenya Medical Research Institute, Nairobi, Kenya, A. ARAGON,
C. CUNNINGHAM and E.S. LOKER, Department of Biology, The University of New Mexico, Albuquerque NM, USA.
Chemotherapy for schistosomiasis relies almost exclusively on Praziquantel (PZQ), but some field
isolates have shown decreased sensitivity to the drug. A Kenyan patient treated more than 20 times with
PZQ was observed to continue passing viable eggs. Miracidia from these eggs (“86”) show reduced
sensitivity to PZQ in an in vitro assay when compared to miracidia from other individuals. To confirm
this result, we performed an in vivo assay for PZQ sensitivity using mice as the definitive host. Mice were
infected with 200 cercariae and seven weeks later divided into two groups and treated for four consecutive days with either (i) 250 mg/kg/day PZQ (p.o.) dissolved in 2% Cremaphor EL or (ii) 2% Cremaphor EL alone. Two weeks later, the mice were perfused and the total number of adult worms recovered
was recorded. Three other isolates of Schistosoma mansoni also were investigated in this way; a Kenyan
isolate (“N”) derived from an individual who had never been treated with PZQ and two established
laboratory strains, PR1 and NMRI. In all trials, the dose of PZQ used was enough to kill more than
97% of the adult PR1 and NMRI worms, whereas this same dose was capable of only reducing the
worm burden by 28% and 25% for the “86” and “N” isolates, respectively. This lack of sensitivity is
consistent with the common designation of “resistance.” Currently, we are developing RT-PCR based
assays to determine whether PZQ has a differential effect on the transcriptional responses of each of the
field and lab isolates.
184
Gene Expression Analysis of Heat Shocked Schistosoma mansoni and Its Application in the Development of Assays to Monitor Praziquantel Resistance. R. IMANI*, A. ARAGON and C. CUNNINGHAM,
Department of Biology, The University of New Mexico, Albuquerque NM, USA.
Schistosomes are digenetic trematodes that chronically infect approximately 200 million people. The life
cycles of schistosomes are complex, including both a vertebrate and invertebrate host. While developing
within these hosts, they must withstand hostile immune responses and, during the transition between
hosts, survive in an aquatic environment in which they may encounter pathogens and pollutants.
Throughout their life cycle, they also must survive temperatures ranging from 20–40°C. To cope with
these challenges, schistosomes probably differentially express proteins that contribute to defense and
stress responses. We hypothesize that many of the genes that are regulated differentially in response to
external stressors also play a role in protecting the schistosome from the adverse effects of host immunity.
We have performed a longitudinal analysis of the transcriptional response to heat stress (42°C, 3.5 hours)
by Schistosoma mansoni adult worms using a microarray containing 7,330 unique S. mansoni elements. In
all, a total of 60 genes underwent a four-fold change in their level of transcription over the duration of
the experiment. The standard treatment for Schistosome infection is 40 mg/kg of praziquantel (PZQ).
Using heat shock induced genes as markers of transcriptional activity, we performed in vitro PZQ
titration experiments on adult worms to determine the lethal dosage. When exposed to PZQ concentrations of ≥ 80 µg/ml for 30 minutes, adult worms fail to elicit an active heat shock response. This is a
significant improvement in sensitivity compared to current field assays that measure the response of
schistosomes to PZQ and which are used to detect increasing sensitivity to the drug.
185
Study of the Reproductive Capacity of Trichinella spiralis Recovered from Experimentally Infected Mice
after Under-dose Treatment with Albendazole or Mebendazole. J.L.A. DE LA ROSA, Laboratory of
Tissular Helmints, Institute of Epidemiological Diagnostic and Reference, Ministry of Health, México
DF, N. ÁLVAREZ, Institute of Epidemiological Diagnostic and Reference, Ministry of Health, México DF,
and A. GÓMEZ-PRIEGO*, Department of Microbiology and Parasitology, School of Medicine, UNAM,
México DF, México.
135
ABSTRACTS
Successful medical treatment of parasitic infections mainly depends of appropriate systemic therapeutic
levels reached, which are related to the adequate doses. When doses are inadequately low, therapeutic
levels are not achieved, and thus it is likely that some parasites can survive after treatment period, which
explains in part a number of the treatment’s failure. It is not clear, however, what happens with this
parasite sub-set, specifically in regard to its reproductive capacity. Thus, results about the reproductive
capacity of Trichinella spiralis recovered from experimentally infected mice after under-dosed treatment
with albendazole (ALB) or mebendazole (MEB) are presented. Male C57/BL mice were infected with 10
± 0.5 muscle larvae (ML) per gram of body weight and treated at the enteral phase of the infection with
a single dose (20 mg/kg) of albendazole, mebendazole or praziquantel (PZQ); at the parenteral phase,
treatment was for seven days. A worm recovery index (WRI) was calculated and data was analyzed with
the factorial ANOVA test and by one-way ANOVA test. A reduction of 72.9, 80.6 and 17.2% in the
parasitic load of adult worms (AW) was observed after treatment with ALB, MEB or PZQ, respectively,
while reduction of ML was 89.9, 89.7 and 19.3%, respectively. No newborn larvae (NBL) was found
after in vitro culture of AW recovered after ALB or MEB treatment, but several NBL was detected in
PZQ and control-derived AW. Recovered larvae from these mice were used to infect naïve mice; after 45
days of infection, similar reproductive capacity index (RCI) was observed between groups (p = 0.323,
one-way ANOVA), either when treatment was applied in the enteral (RCI ALB = 51.6 ± 12.1 and RCI
MEB = 49.2 ± 14.) or parenteral (RCI ALB = 52.2 ± 14.0 and RCI MEB = 51.9 ± 11.8) phase of
infection; RCI of non-treated ML was 59.5 ± 7.7. These results suggest that since there is a temporary
effect of ALB and MEB on adult worms, the life cycle was not interrupted at all, which must be taken in
account in practical strategies for massive control activities, where under-dosage is administered frequently.
186
Comparison of Moxidectin + Praziquantel, Ivermectin and Febantel + Metriphonate Efficacy Against
Horse Parasites in Three Mexican Regions. M.C. GUERRERO-MOLINA*, E. ROMERO-CALLEJAS,
Departamento de Parasitología, Facultad de Medicina Veterinaria y Zootecnia, UNAM, P. OCHOAGALVAN, Departamento de Genética y Estadística, Facultad de Medicina Veterinaria y Zootecnia,
UNAM, and Y. ALCALA-CANTO, Departamento de Parasitología, Facultad de Medicina Veterinaria y
Zootecnia, UNAM, México DF, México.
The aim of this study was to compare the nematodicidal efficacy of three anthelmintics in horses located
in three different regions of México. In order to assess this objective, 300 horses were assigned to three
treatment groups. Group A (South-Veracruz), group B (North-Nuevo León and Tamaulipas) and group
C (Central-Edo. de México). All animals received moxidectin 2% + praziquantel 12.5%; ivermectin
1.87%, and febantel 7.83% + metriphonate 37.35% orally. Fecal samples were collected on days -7, 0,
30, 60 and 90, and analyzed by McMaster, Baermann and fecal culture techniques. Mean, standard
deviation, decrease in number of nematode eggs/g (efficacy), percent of nematode genus, species and
time of reinfection were calculated. Efficacy on day 30 was 96.67%, 99.89% and 98.06% for Veracruz
horses treated with moxidectin + praziquantel, ivermectin, and febantel + metriphonate, respectively.
Efficacy in Nuevo Leon was 97.15%, 98.81% and 89.36% for moxidectin + praziquantel, ivermectin
and febantel + metriphonate, respectively. Efficacy in Tamaulipas was 100% for moxidectin + praziquantel and ivermectin, but of 92.12% for febantel + metriphonate. Efficacy in group C was 90.27%,
88.34% and 88.09% for moxidectin + praziquantel, ivermectin, and febantel + metriphonate, respectively. Detected nematode genus and species were as follows: Cyathostomun spp, Strongylus equinus, S.
edentatus and S. vulgaris. Reinfection occurred after treatment in Veracruz and Tamaulipas with febantel
+ metriphonate and praziquantel on day 30 and ivermectin on day 60; in Nuevo León, with ivermectin
and febantel + metriphonate (day 30); and moxidectin + praziquantel (day 90); and with the three
drugs (day 30) in edo. de México. It is concluded that moxidectin + praziquantel significantly decreased
nematode eggs/g in contrast to ivermectin and febantel + metriphonate in group C. Moreover, moxidectin + praziquantel and ivermectin showed a similar reduction of eggs/g in Tamaulipas horses.
187
Prevalence of Sheep Farms with Anthelmintic Resistant Nematodes in Two States of Tropical México.
J.F. TORRES-ACOSTA*, FMVZ, Universidad Autónoma de Yucatán, Mérida, Yucatán, México, C.
136
ABSTRACTS
LÓPEZ-CEVANTES, A.M. ORTÍZ-DE-MONTELLANO-NOLASCO, Instituto Tecnológico de China,
Campeche, R. CAMARA-SARMIENTO, J. CANTO-DORANTES, FMVZ, Universidad Autónoma de
Yucatán, Mérida, Yucatán, C. MARTÍNEZ-ORTÍZ-DE-MONTELLANO, Instituto Tecnológico de China,
Campeche, J. RODRÍGUEZ, H.L. CANUL-KU, F. TIRADO-MUNOZ, A.J. AGUILAR-CABALLERO,
FMVZ, Universidad Autónoma de Yucatán, Mérida, Yucatán, México, and B. ROBERTS, Veterinary
School, University of Florida, Gaineswille FL, USA.
Anthelmintic resistance is an important problem for sheep farming in the world. In México, the scale of
the problem has been poorly evaluated, particularly in hot tropical areas. Twenty-four commercial sheep
flocks from Yucatán and twenty flocks from Campeche (two tropical states in the Gulf of México) were
surveyed. Fecal Egg Count Reduction Tests (FECRT) were performed for each flock to determine the
presence of resistant gastrointestinal nematodes (GIN). Animals were assigned to one of four different
groups (n = 11 to 15 animals): (a) untreated control group, (b) fenbendazole group (BZ) (10 mg/kg
per os), (c) levamisol group (LEV) (7.5 mg/kg s.c.), and (d) macrocyclic lactones (ivermectin or moxidectin) group (ML) (0.2 mg/kg s.c.). Animals were deprived of access to food (either browsing/grazing
or supplement) for a period of 16 hours prior to treatment. FECRT and larval cultures were performed
prior to and 10 to 12 days after anthelmintic (AH) treatment. Prevalence of BZ resistant GIN was 78%
in Yucatán and 74% in Campeche. Prevalence of ML resistant GIN was 17% in Yucatán and 65% in
Campeche. Prevalence of multi-resistant GIN (BZ and ML) was 9% in Yucatán and 53% in Campeche.
There was no sheep flock with LEV resistant nematodes. While Haemonchus spp. was found to be
resistant to both BZ and ML, Trichostrongylus spp. was found resistant to ML in Yucatán and resistant to
BZ and ML in Campeche. (Financial support was obtained from Fundacion Produce Yucatán and
Fundacion Produce Campeche.)
188
Use of Repetitive Doses of Combination of an Albendazole–Ivermectin Association Against Toxocara
canis Encysted Larvae in White Mice. J.P. MARTÍNEZ-LABAT*, C. FERNÁNDEZ-GONZÁLEZ and C.
ORTÍZ-RIVERA, Laboratorio de Parasitologìa, Facultad de Estudios Superiores Cuautitlàn, UNAM,
Mèxico.
An albendazole–ivermectin combination was evaluated as an alternative to eliminate T. canis encysted
larvaes using a mouse model. Sixty CD-1 male white mice were distributed randomly in six groups of 10
mice each. One group, used as a non-inoculated control, was administered with ivermectin diluent. A
second control group was orally inoculated with 500 T. canis larvae eggs, but it did not receive any
treatment. Both groups were euthanized at 30 days post-inoculation. The remaining four groups were
inoculated orally with 500 T. canis larvae eggs and one month post-inoculation were monthly treated
during four months with ivermectin–albendazole at a dosage of 200 mcg kg-1 and 5 mg kg-1, respectively.
At an 30-day interval, each group was euthanized (30, 60, 90 and 120 days post-treatment) to dissect
and obtain brain, liver, lung, kidney and 1 g of pelvic right muscle. The latter was multiplied with the
total carcass. The organs were digested artificially for 48 hours and the tissue digestion sediments were
observed microscopically to determine the treatment efficacy on the basis of larvae recovery of each
tissue. It was found that under a four-month treatment, the combination of albendazole–ivermectin
shown an larvae elimination average of 91.35%. In brain was obtained a 80.08% efficacy, while in
skeletal muscle the efficacy was of 98.47%. The ANOVA results (α = 0.05) were significant for total
parasitism (Fc = 6.0568) and skeletal muscle (Fc = 3.5865), but not in brain (Fc = 1.8097). The results
showed that the combinatios is effective to eliminate extracerebral larvae, but it has limited effects on
brain. It is proposed to increase albendazole dosage in order to achieve a superior efficacy in brain tissue.
189
Anthelmintic Effect of Albendazole in Different Doses Against Toxocara canis Encysted Larvaes in White
Mice. J.P. MARTÍNEZ-LABAT* and E. JARAMILLO-ALCÁNTARA, Laboratorio de Parasitologìa, Facultad
de Estudios Superiores Cuautitlàn, UNAM, Mèxico.
This study was performed to determine the effective single dosage of albendazole using four different
protocols to identify the most appropiate against T. canis larvae stage that causes zoonosis from dogs to
humans due to its adaptability and association. For this purpose, 60 CD-1 female albine mice were
placed in six experimental groups. Five of them were infected with 1,000 viable larvae eggs of T. canis by
137
ABSTRACTS
gastric gavage. The remaining group was used as a control. One month post-inoculation, the animals
were treated with a single shot of albendazole at a dosage 5, 50, 100 and 400 mg/Kg of weight per
group. After 30 days, the mice were euthanized and dissected to extract 1g of striated skeletal muscle,
brain, lungs, liver and kidneys. The tissues were minced with scissors and artificially digested in tubes in
a bacteriological oven at 37ºC. The treatment efficacy was evaluated on the basis of amount of larvae
recovered from each organ; efficacies were obtained of 19.32%, 33.62%, 38.69% and 41.91% for the
dosages of 5, 50, 100 and 400 mg/Kg of weight, respectively. These results were statistically significant
by ANOVA since a significant larvae reduction was observed. In conclusion, albendazole was shown to
be effective in killing T. canis encysted larvaes with a direct, proportional effect to the dosage and exhibited a capability to destroy larvae located in the brain. Further work is necessary to corroborate the
obtained data most preferable at repetitive dosages in order to determine the best antihelmintic actitivity.
190
Anthelmintics and Intestinal Obstruction Due to Ascaris lumbricoides. O. VAZQUEZ-TSUJI*, Laboratorio de Biologia Molecular y Microscopia Electronica, Facultad Mexicana de Medicina, Universidad La
Salle, M.A. YAMASAKI-NAKASHIMADA, Servicio de Inmunologia, Instituto Nacional de Pediatria, T.
CAMPOS-RIVERA, Servicio de Parasitologia y Micologia, Instituto Nacional de Pediatria, P.
GUTIÉRREZ-CASTRELLON, Instituto Nacional de Pediatria, and R.H. MEDINA-CAMPOS, Residente de
Med Interna, Instituto Nacional de Ciencias Médicas y Nutrición, Salvador Zubiran, México.
Objective: The purpose of the study was to evaluate the use of anthelmintics drugs as a risk factor of
intestinal obstruction by A. lumbricoides. Methods: We analyzed the clinical records of 199 children
admitted with the diagnosis of intestinal obstruction due to Ascaris lumbricoides (IOA). There were two
groups: Group A (n = 66) were children with intestinal obstruction, and Group B (n = 133) were
children with no complications. A comparative analysis of clinical data of both groups was made by
means of chi square with Yates correction and a stratified analysis by means of chi square. Possible
confounding elements were overcrowding, age and the use of antiparasitic drugs. The calculus of risk
factors for IOA was done by means of contingency tables 2 x 2 and Odds ratio with a CI of 95%.
Results: Twenty-seven patients (40.90%) in group A (n = 66) had been given anthelmintics medications
prior to the intestinal obstruction: 14, mebendazol (51–85%); two, albendazol (7.4%); eight, a nonspecified anthelmintic (29.6%). Five patients received it between one and seven days prior to the obstruction; two received it seven days prior to the complication. In the control group, only 7% had taken
the anthelmintic one to seven days before the diagnosis of uncomplicated intestinal ascariasis was made.
With a logistic regression of a x 2 = 38.15 gl, p < 0.000 was obtained. Discussion: of the probable risk
factors analyzed in this study, the only one capable of influencing and predicting the presentation of
intestinal obstruction by A. lumbricoides in children was the prior anthelmintic treatment, particularly
with mebendazol.
191
Presence of Naegleria fowleri in a Thermal Spa with a Geyser in México. E.M. GALLEGOS-NEYRA*, A.
CALDERÓN-VEGA, K. RANGEL-RUIZ, Laboratorio de Patógenos Emergentes, Facultad de Estudios
Superiores Iztacala, UNAM, and P. CASTILLO-NAVA, Facultad de Estudios Superiores Iztacala, División
de Investigación y Posgrado,UNAM, México.
Naegleria fowleri is considered to be one of the most pathogenic free-living ameba known at present,
causing fatal Primary Amoebic Meningoencefalitis (PAM).This ameba is thermophilic and is founded
frequently in water bodies with temperatures that surpass 37°C. The aim of this research was to isolate
and identify Naegleria fowleri in the pools of a thermal water spa in the most important aquatic corridor
in the State of Hidalgo, México. In this spa, all pools are filled with water from a natural geyser.The
following parameters were measured in situ: water and atmospheric temperatures, pH, conductivity,
dissolved oxygen (DO), faecal coliforms and total bacteria. Water samples were concentrated by centrifugation and sediment seeded in non-nutrient agar plates with Enterobacter aerogenes (NNE) to stimulate
the amebic growth, and the N. fowleri isolates were identified taxonomically by phase contrast microscopy. To confirm the taxonomy of N. fowleri, a nested PCR analysis was performed to amplify a specific
DNA segment of 110 bp. A total of 82 isolates AVL were obtained in four samplings during a year. By
morphological characterization and nested PCR, 19 isolates were identified as Naegleria fowleri that grow
138
ABSTRACTS
at temperatures in the range of 33.4–52.4°C. N. fowleri were found throughout the system of pools.The
physiochemical factors seem to impact in a positive way the presence of the ameba, although these
parameters registered high values, especially the temperature, conductivity and pH. We emphasize that
the presence of thermophilic Naegleria fowleri must be consider seriously by the local community authorities in order to prevent any cases of PAM.
192
Heterophyid Trematodes Are Correlated with Emergent Ocular Pathologies in Cichlid Fishes from
Nicaragua. M.I. JIMÉNEZ-GARCÍA*, Division de Estudios de Posgrado e Investigacion, Instituto Tecnologico de Boca del Rio, Boca del Rio, Veracruz, México, J.K. McCRARY, Universidad Centroamericana,
Managua, Nicaragua and College of Natural Resources, Virginia Tech, Blacksburg VA, USA, and V.M.
VIDAL-MARTÍNEZ, Departamento de Recursos del Mar, Centro de Investigacion y de Estudios Avanzados, Mérida, Yucatán, México.
Beginning in 2000, a surge in incidence of cataracts and blindness among native Cichlid fishes in Lake
Apoyo, Nicaragua, has occurred. Until now, however, the cause(s) of these emerging pathologies has
remained obscure. In order to detect potential pathogens that could act as agents of ocular pathologies,
we examined (November–December, 2003) the ocular regions of “healthy” Amphilophus c.f. citrinellus
“short” (N = 49) and blind (N = 30) cichlids. Fishes were identified as blind or seeing by direct observation of their behavior while scuba diving. Most, but not all, of the blind fishes had cataracts, or their
eyes were missing. Sight impairment among the fishes was determined easily by their swimming pattern.
Preselected fishes then were captured by harpoon. There were significant differences between the prevalence (28% vs. 90%), mean abundance (1.3 ± 3.0 vs. 18 ± 16), and infection range (0–11 vs. 0–79) of
“healthy” and blind fishes, respectively. Heterophyid cysts in the tissues behind the eye correlated
significantly with ocular pathologies in A. c.f. citrinellus “short.” Blindness among this taxon also corresponded to a decrease in body condition. Furthermore, the blind fishes appeared not to breed again, and
they were vulnerable to eye-plucking behavior by other fishes. Potential sources of stress to native
cichlids, including recent fish species introductions, and other ecological and evolutionary factors linked
to the process of speciation in the lake may be playing a role in this sustained emergent disease in Lake
Apoyo.
193
Entomological Assessement of Chagas Disease Vectors in Southern Belize. R. POLONIO, M.J.
RAMIREZ-SIERRA and E. DUMONTEIL*, Laboratorio de Parasitología, CIR, Universidad Autónoma de
Yucatán, Mérida, Yucatán, México.
Chagas disease is a major public health problem from South America to the U.S., with approximately
100 million people at risk and between 16 and 18 million infected. Chagas disease is known to occur in
Belize, but little is known about the prevalence of Trypansoma cruzi infection in the Belizean population
or entomological aspects of Chagas disease. We performed an entomological survey of triatomines in
southern Belize. Triatomines bugs were collected by community participation in 20 villages of the
southern district of Toledo and analyzed for infection by T. cruzi by microscopic examination and/or
PCR. More than 200 bugs have been collected from 19 villages, indicating a wide distribution, and all
were identified as T. dimidiata. Eighty-three percent were adults (48% males, 52% females), and 16%
were larval stages. Thirty percent were infected by T. cruzi. Triatomines were more abundant during the
hot season (March–July) compared with the cooler season (September–February). This study confirmed
that there is a risk for Chagas disease transmission in southern Belize, and the geographic distribution of
T. dimidiata seemed to correlate well with available seroprevalence data from human populations. These
data will be valuable for the implementation of vector and epidemiological surveillance programs in the
region.
194
Survivorship of Cyathocotyle bushiensis and Its Snail Host Following Experimental Desiccation. E.M.
KOPPEL* and R.E. SORENSEN, Minnesota State University, Department of Biological Sciences,
Mankato MN, USA.
139
ABSTRACTS
Bithynia tentaculata is an exotic aquatic gastropod present in areas adjacent to the Great Lakes in North
America. This species is known to transmit Cyathocotyle bushiensis and Sphaeridiotrema globulus trematodes. These parasites have been associated with the mortality of migrating waterbirds. Due to the
dramatic impacts these parasites have on waterbirds, a better understanding of factors influencing the
transmission of B. tentaculata to novel sites is important. The ability of these snails to withstand desiccation impacts the role accidental overland transport has on transmission of C. bushiensis and S. globulus. If
B. tentaculata is capable of surviving periods of desiccation associated with overland transport, it could
colonize new sites and possibly transmit the parasites to new populations of waterbirds. An experimental
desiccation study was performed using B. tentaculata containing natural levels of S. globulus and C.
bushiensis metacercariae. These snails were housed under laboratory conditions and subjected to a 35-day
desiccation period. During the desiccation, a subset of these snails were revived weekly and dissected.
Metacercariae of C. bushiensis from these snails were collected and counted. A subset of the mature cysts
from each snail were placed in Earle’s BSS solution and incubated at 40° C. Metacercariae that excysted
were considered viable and infective. At the end of the 35-day study, more than 50% of the B. tentaculata
subjected to desiccation were able to revive once placed in water. Additionally, mature C. bushiensis were
found to be infective in surviving snails as well as in the decaying tissue of deceased snails. This study
provides evidence that both snail and parasite are potentially hardy enough to survive overland dispersal
and subsequently colonize novel lake and river systems, thus impacting waterbirds in these areas.
195
Parasite Characterization in Juvenile and Fry Tilapias Cultured in Veracruz, México. M.I. JIMÉNEZGARCÍA*, M.D. CASTAÑEDA-CHÁVEZ, S.B. CRUZ-ORDÓÑEZ and M.D. PÉREZ-FOSADO, Division
de Estudios de Posgrado e Investigacion, Instituto Tecnologico de Boca del Rio, Boca del Rio, Veracruz,
México.
Veracruz State is the main tilapia producer in México. Nevertheless, in spite of the economic and social
potential of this activity, there are no studies about the infection parameters of parasites in tilapia farms,
and therefore of the potential risk of infectious diseases in cultured fishes in Veracruz. Therefore, we
registered the occurrence of parasites (protists, fungi and helminthes) and their abundance in juvenile
Oreochromis niloticus, O. aureus (130–200 mm in total length), fry tilapias O. niloticus and a red hibrid
“pargo” (10 ± 1 mm in total length). From December 2005 to December 2006, four farms were
sampled three times a year: “nortes” season (December–January), dry season (April–May) and rainy
season (August–September). The fish from the three farms belong to Nile tilapias, and the other to O.
aureus. We searched for ectoparasites and endoparasites. The skin, mucus, fins, gills and stomach were
the sites most inhabited. With respect to fry fishes, 30 fishes per tilapia group (Nile and “pargo”) were
analyzed in January 2007. The parasites registered in this study includes 10 species: three protists,
Trichodina sp, Ichthyophthirius multifiliis, and Epistylis sp.; six monogenean species, Cichlidogyrus sp, C.
sclerosus, C. tilapiae, C. longicornis, Gyrodactylus sp, and Enterogyrus sp, and the fungus, Saprolegnia sp.
The most frequent and abundant parasites were Cichlidogyrus genus: prevalence between 90 and 100%,
mean abundance: 64 ± 50 monogeneans per examined host, and infection range: 0–181, and Trichodina
sp.: prevalence between 70 and 100%, mean abundance: 73 ± 110 parasites per examined host, and
infection range: 15–420. In the case of fry tilapias, Trichodina sp.: prevalence 100%, mean abundance:
351 ± 360, and infection range: 22–2,500, and Gyrodactylus sp.: prevalence 77%, mean abundance: 8 ±
5, and infection range: 0–22. “Ich” and Saprolegnia sp. occurred especially in colder months.
196
Self-medication as an Anti-parasitic Adaptation in Japanese Macaques. C.J. DAGG, Department of
Anthropology, University of Georgia, Athens GA, USA.
Conservation biologists are recognizing infectious disease as an increasing challenge to wildlife conservation. The emerging discipline of Conservation Medicine considers disease in endangered populations as a
measure of risk, and as a focus for intervention and management. However, detailed parasitological
surveys of endangered populations are rare. I report on the first focused study of parasite ecology and
anti-parasitic self-medication in Yaku Japanese macaques (Macaca fuscata yakui), a subspecies classified as
endangered in the IUCN Redlist, endemic to the island of Yakushima. For one full year, focal observations are being carried out on 10 adult females in a habituated group. Fecal samples are collected twice
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daily, tested for nematode parasites using qualitative and quantitative microscopy, and desiccated to
determine water content as a measure of diarrhea. Analyses indicate infection with one or more of
Oesophagosomum aculeatum, Trichuris sp, Streptopharagus pigmentatus and Strongyloides fuelleborni. of
these, O. aculeatum and S. fuelleborni frequently present pathological symptoms such as diarrhea and
ulceration. Literature and preliminary observations on the ~135 dietary plant species have narrowed five
as potentially medicinal: Rhus succedanea, Trema orientalis, Zanthoxylum ailanthoides, Lagerstroemia
subcostata and Miscanthus sinensis. Initial data suggest anti-parasitic pharmacological action in four of
these species, and physical purging properties in one, akin to ‘leaf-swallowing’ behaviour in chimpanzees.
Conclusive proof of self-medication, however, requires analysis of the entire season, including the highrisk period after the rainy season in June. Nonetheless, the effect of parasitosis on host fitness and the
host’s response to this stress have been subject to long coevolution, and it is likely that innovative species
such as macaques may have adapted such behavioral defenses. Studying the ingestion of natural plant
resources, primarily for their medicinal properties, may allow parasite stress and ecological health services
to be considered in reserve design, and habitat degradation assessment.
197
In vitro Activity of Calcium Hydroxide Against Giardia lamblia Cysts. B. NOGUEDA-TORRES*, R.M.
SÁNCHEZ-MANZANO, Departamento de Parasitología, Escuela Nacional de Ciencias Biológicas, IPN,
México DF, B. CHÁVEZ-MUNGUÍA, Departamento de Patología Experimental, CINVESTAV, México
DF, A. MÁRQUEZ-NAVARRO, Departamento de Parasitología, Escuela Nacional de Ciencias Biológicas, IPN, México DF, and A. CAMACHO-VERA, Departamento de Zoología, Escuela Nacional de
Ciencias Biológicas, IPN, México DF, México.
Giardia lamblia (syn. Giardia intestinalis, Giardia duodenalis) is a flagellated, unicellular eukaryotic
microorganism that commonly causes diarrheal disease throughout the world. Suspensions of calcium
hydroxide (Ca(OH) 2) up to 0.25% were parasiticidal against Giardia lamblia cysts, and this effect was
proportionally direct to concentration and time of contact cyst/calcium hydroxide. A suspension of
Ca(OH) 2 0.5% reduced the presence of viable cysts up to 22 ± 2% after 10 minutes of contact, while
concentrations of 1 and 2% eliminated the 98 ± 2 and 100%, respectively (LD50 = 0.36% and LD90
= 0.84%). After the treatments, the transmission microscopic study revealed generalized damages in
both the cytoplasm and the membrane structure, and deposits of electrodense material in the cytoplasm
of the cyst also were observed. The low cost of the Ca(OH) 2, easy handling, antibacterial activity
backgrounds, and the parasiticide activity against Giardia lamblia obtained in this work shows its potential use in the disinfection of vegetables and drinking water for human and animal consumption in
communities where the disposition of drinkable water is limited.
198
Seasonal Variation of the Metacercaria Parvatrema polymesoda on the Marine Clam, Polymesoda
maritima, in a Mangrove System of Progreso, Northern Yucatán Peninsula. K.P. RODRÍGUEZ MEDINA*
and S. GUILLÉN HERNÁNDEZ, Laboratorio de Biologia Marina, Campus de Ciencias Biologicas y
Agropecuarias, Universidad Autónoma de Yucatán, Yucatán, México.
Mollusks have an important role within the life cycle of digeneans since the former act as intermediate
hosts. Gastropods act as first intermediate hosts of many digenean species, while some bivalves are
second intermediate hosts. In México, some studies are available on gastropods as intermediate hosts of
helminths of medical importance. Studies of helminths of bivalves, however, are scarce and have been
focused on bivalve species of commercial importance. This work elucidated the possible seasonal incidence of the larval phase of Parvatrema polymesoda on the marine clam Polymesoda maritima in a mangrove system of Progreso, Yucatán, México. Monthly samples were taken during a year (June 2005–May
2006), from which a total of 504 individuals of Polymesoda maritima were examined. Parvatrema polymesoda was identified and infection levels were obtained, the latter base on prevalence, mean abundance
and mean intensity. Total prevalence was 39%, mean abundance 111, and mean intensity was 284
individuals per infected host. October and November showed the highest values of prevalence and mean
abundance. There was a significant relationship between the number of metacercaria and the clam sizes
(ANOVA, F = 18.48, p = 0.00).
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199
Helminth Communities of the “Leopard Frog” Rana brownorum Sanders, 1973 (Anura: Ranidae) From
Yucatán, México. C.A. YAÑEZ-ARENAS* and S. GUILLÉN-HERNÁNDEZ, Laboratorio de Biologia
Marina, Campus de Ciencias Biologicas y Agropecuarias, Universidad Autónoma de Yucatán, Yucatán,
México.
The leopard frog (Rana brownorum) is one of the most abundant and characteristic species present in
temporal and permanent water bodies of the Yucatán Peninsula. This frog is an important part in the diet
of a great variety of vertebrates living there. Although there are some studies relating it with parasites in
México, there are no studies on this frog as a host in Yucatán. From June 2004 to May 2005, a total of
84 leopard frogs, R. brownorum, were collected from three different localities (Celestun, Ria Lagartos and
Yalahau) in Yucatán. Helminth communities were studied at two different levels (component community
and infracommunity) and parasite infection levels were obtained. Twelve helminth species were found:
seven nematodes, four digeneans and one acanthocephalan. It seems that the helminth communities
structure of this frog is related with its low vagility (71% of the helminth species infect R. brownorum via
penetration) and to its feeding habits. Different helminth species showed the highest values of infection
(prevalence, mean abundance and mean intensity) in each locality. The nematode Subulascaris sp. showed
the highest values of prevalence and mean abundance in Celestun, the nematode Aplectana incerta in
Yalahau, and the digenean Langeronia macrocirra in Ria Lagartos. A digenean Glypthelmins brownorumae
had the highest mean intensity in Celestun, L. macrocirra in Yalahau and both digeneans in Ria Lagartos.
At the component community level, statistically significant differences were found in richness values
between localities. No differences, however, were found in diversity values. At the infracommunity level,
no differences were found in richness and diversity values between localities.
200
Endohelminths of the Threespine Stickleback, Gasterosteus aculeatus, from Two Locations in Western
North America. A. CHOUDHURY*, Division of Natural Sciences, St. Norbert College, DePere WI, J.
CHENG, Department of Natural Sciences and Mathematics, Dominican University of California, San
Rafael CA, J. TRACEY, Division of Natural Sciences, St. Norbert College, DePere WI, M. KOLIPINSKI,
National Park Service, Pacific West Regional Office, Oakland CA, and S. GHOSH, Department of
Natural Sciences and Mathematics, Dominican University of California, San Rafael CA, USA.
The endohelminth fauna of the threespine stickleback, Gasterosteus aculeatus, from two widely separated
geographical locations (Campbell Creek, British Columbia, and the San Francisco Bay area, California) is
reported and compared. The endohelminth fauna of sticklebacks in Campbell Creek included: Cyathocephalus trunctaus, Proteocephalus sp., Bunodera mediovitellata, Neoechinorhynchus sp., Eustrongylides sp.,
and Schistocephalus sp. In comparison, parasites in sticklebacks sampled from two creeks and one lagoon
in the San Francisco Bay area included: Bunodera mediovitellata, Proteocephalus sp. (an opecoelid new to
science), Eustrongylides sp., Schistocephalus sp., Clinostomum sp. and Cryptocotyle sp. Similarities in the
parasite fauna of sticklebacks from the two widely separated locations are due to some widely distributed
and generalist (for fish hosts) larval helminths, but also due to parasites such as B. mediovitellata that are
specific to this stickleback species and whose known geographical range is increased greatly as a result of
the Californian study. The ecology and diadromous nature of the threespine stickleback also are reflected
in their parasites from both geographical areas. All the parasites reported from California appear to be
native species and represent several new host records and range extensions.
201
Susceptibility of Fry Tilapias (Oreochromis niloticus, Stirling and Rocky Mountain, and The Hybrid
Pargo cereso) to be Infected by Ectoparasites. S.B. CRUZ-ORDÓÑEZ*, M.I. JIMÉNEZ-GARCÍA, M.D.
CASTAÑEDA-CHÁVEZ and C. MATO-LÓPEZ, División de Estudios de Posgrado e Investigación,
Instituto Tecnológico de Boca del Río, Veracruz, México.
In México, tilapia is one of the most important species in aquaculture, especially the Nile tilapia, Oreochromis niloticus, Stirling and Rocky Mountain, and the red hybrid, Pargo cereso. These fish tilapias have
genetic features that are expressed in appropriate phenotypes for their culture; nevertheless, the knowledge about differential susceptibility to be parasitized is scarce. Therefore, the aim of this study was to
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determine experimentally if young O. niloticus, Stirling and Rocky Mountain, and the Pargo cereso hybrid
show different susceptibilities of being infected by ectoparasites. The fry tilapias were set in three interconnected tanks (recirculation system), which have antecedents of Trichodina, Gyrodactylus and Cichlidogyrus ocurrence. The fishes were exposed to such parasites during two weeks. After that, 30 fishes of each
tilapia group were analyzed. The second part of this study included the application of a treatment
(formalin 250 ppm) during three days in order to determine a possible effects of this chemical substance
in the parasitic burden. In the first parasite examination, no significant differences were found in the
infection average by Trichodina (351 ± 360, 329 ± 214, and 355 ± 216), Gyrodactylus (8 ± 5, 7 ± 5,
and 6 ± 5), and Cichlidogyrus (0.3 ± 0.6, 0.2 ± 0.7, and 0.1 ± 0.3) among O. niloticus, Pargo cereso, and
Rocky Mountain, respectively. Finally, after the treatment, there were no findings of ectoparasites.
202
Central America Is an Area of Endemism for Helminth Parasites of Freshwater Fish. G. SALGADOMALDONADO, Instituto de Biología, UNAM, México.
The freshwater fish of Central America are a faunal assemblage distinct from that of North America and
South America, and are parasitized by their own, endemic helminth fauna. This study is a review of
helminth taxonomic composition and distribution in Central America generated through collection of
bibliographic information on the adult helminths of freshwater fish recorded from the Isthmus of
Tehuantepec, México, to the Isthmus of Panama. To date, 105 helminth species have been reported in
this region, parasitizing 16 freshwater fish families. Fifty-eight percent of the helminth species currently
known in the region have been found in three of these families: the cichlids (hosts to 34 helminth
species); Characidae (hosts to 15 helminth species); and Heptapteridae (hosts to 12 helminth species).
of these 105 helminth species, 92% have been recorded only in Central America, meaning they are
endemic. Eight of the 105 have been reported in South America and none in North America. The most
abundant helminth groups in the region (in descending order) are nematodes, trematodes and monogeneans. No helminth family is endemic to Central America. The only suprageneric taxon recognized to
date as endemic to Central America is the monotypic nematode subfamily Neophilometrinae. Seventeen
of the known genera are endemic (10 trematodes, four nematodes, and three monogeneans), 22 are from
South American lineages and two are from North American lineages. The data suggest Central America
is a diversification center for the helminths of freshwater fish since this helminth fauna consists of species
that apparently originated and evolved in this region. Most of the reported species are endemic and
derive from generalized South American genera. The almost total lack of differentiation of endemic
suprageneric taxons and the relatively low number of endemic genera suggest this fauna is young. Its
distribution ranges exclusively from the Transversal Neovolcanic Axis Province (approximately the 19th
parallel) to the Isthmus of Panama. It has not been able to invade Nearctic regions north of the Neovolcanic Axis and is not found in South America.
203
Isolation and Characterization of locus Ehcpadh in a Phagocytosis-deficient Mutant of Entamoeba
histolytica. R. GUZMÁN-MEDRANO*, Laboratorio de Ciencias Básicas, División de Patología, Escuela
de Odontología, Universidad Autónoma de Chihuahua, B.A. CASTILLO-JUAREZ, A. SALAS-CASAS, E.
OROZCO and M.A. RODRÍGUEZ, Departamento de Patología Experimental, Centro de Investigación
y Estudios Avanzados, IPN.
EhCPADH is a complex that participates in the pathogenic mechanism of the parasite Entamoeba
histolytica. An adhesin (EhADH112) and a cisteine protease (EhCP112) constitute this complex. To
determine the importance of these proteins in the phagocytosis of E. histolytica, we analyzed the expression and the sequences of the Ehadh112 and Ehcp112 genes and their intergenic region in a phagocytosis
deficient mutant of this protozoa, the clone L-6. Both sequences and expressions were compared with
their wild-type homologous. RT-PCR assays showed a disminished expression of Ehcp112 and a similar
expression of the Ehadh112 gene in the mutant with respect to the clone A, a wild-type strain. These
genes were cloned on the TOPO 2.1 PCR vector and the plasmids containing the correspondent inserts
were sequenced. Each sequence of the mutant clone was compared with the wild-type strain sequence. In
silico sequence analysis showed changes on the mutant Ehcp112 gene. These changes could modify certain
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phos phorylation and N-glycosilation patterns that could influence the expression or the function of the
proteins that integrate this complex.
204
Alterations in RabB Protein in a Phagocytosis-deficient Mutant of Entamoeba histolytica and in Entamoeba dispar. R. GUZMÁN-MEDRANO*, Laboratorio de Ciencias Basicas, Division de Patologia, Escuela
de Odontologia, Universidad Autónoma de Chihuahua, and B.A. CASTILLO-JUAREZ, R.M. GARCIAPÉREZ, A. SALAS-CASAS, E. OROZCO and M.A. RODRÍGUEZ, Departamento de Patología Experimental, Centro de Investigación y Estudios Avanzados, IPN.
Phagocytosis is an important event in the pathogenic mechanism of Entamoeba histolytica. Rab proteins
are molecular switches by cycling between active GTP-bound and inactive GDP-bound protein forms.
EhRabB is an E. histolytica Rab protein containing the four domains involved in the guanine nucleotide
binding and the motif called “effector region,” involved in interactions with particular effector molecules.
On the other hand, the phagocytosis-deficient clone L-6 was obtained from strain HM1:IMSS. This
clone also is virulence-deficient, but displays normal adherence to RBCs, indicating that a subsequent
event to adherence is responsible of its phagocytosis deficience. We analyzed the EhRabB expression and
its cellular location during phagocytosis in trophozoites of clone L-6. Intriguingly, trophozoites of clone
L-6 express more EhRabB than those of clone A, a wild-type clone. However, the majority of EhRabBcontaining vesicles remained in the cytoplasm of clone L-6 during phagocytosis. To investigate molecular
alterations in EhRabB of clone L-6, we compared the EhrabB gene sequences from clones L-6 and A. We
also isolated, sequenced and compared the RabB protein of Entamoeba dispar. Results showed that
EhrabB gene of clone L-6 is 98.2 and 94.1% identical to rabB genes of E. dispar and clone A, respectively.
The rabB genes from clone A and E. dispar have 92.2% identity. Four out of five amino acids changes in
RabB proteins of clone L-6 and E. dispar are shared. These changes may alter the binding of effector
proteins and the specific subcellular location of EhRabB.
205
Molecular Characterization of the Subunits C160, C128, C82 and C37 of Leishmania major RNA
Polymerase III. L.E. FLORENCIO-MARTÍNEZ*, C.M. GOMEZ-HURTADO, I.I. SÁNCHEZSANTAMARIA, N.E. PADILLA-MEJIA and S. MARTÍNEZ-CALVILLO, UBIMED, FES Iztacala, UNAM,
Tlalnepantla, Edo. de México, México.
Parasites of the genus Leishmania are trypanosomatid protozoans that are transmitted to mammals by the
bite of an infected sand fly. They exhibit atypical mechanisms of gene expression, including polycistronic
transcription. Individual mRNAs are generated from the precursor by trans-splicing, which adds a 39-nt
capped spliced-leader (SL) RNA to the 5r-end, and by polyadenylation at the 3r-end. Our research group
is interested in the study of transcription by RNA Polymerase III (Pol III) from L. major, which synthesizes small essential RNAs, such as tRNAs, 5S rRNAs and snRNAs. In yeast, Pol III is made up of 17
subunits, which are essential for cell survival. In L. major, TAP-tag purifications have led to the identification of 11 Pol III subunits, including C160, C128, C82 and C37. The largest subunits, C160 and C128,
contain the catalytic center for RNA polymerization. C82 is involved in transcription initiation by
interacting with TFIIIB, while C37 participates in transcription termination and reinitiation. In order to
increase our knowledge about transcription in L. major, we have started the characterization of these four
Pol III subunits. First, we searched for putative functionally important regions in the four Pol III subunits by performing alignments of the protein sequences with homologues of other organisms. C160 and
C128 showed a high degree of conservation among all the species analyzed, with 41 and 48% sequence
identity between L. major and human, respectively. C82 and C37 presented low sequence conservation,
with 13 and 11% sequence identity between L. major and human, respectively. We also performed RTPCR assays to localize the processing signals (SL acceptor sites and polyadenylation regions) in the
mRNAs of the four subunits. The SL acceptor sites corresponded to AGs located between 38 and 536
bp upstream of the start codons. Currently, we are performing Northern-blots to analyze the size and
abundance of the mRNAs of the four genes in different stages of the parasite.
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206
Functional Analysis of the Polyadenylation Signals in Trichomonas vaginalis. V. FUENTES-MORALES*,
M.G. BARRERA-ANDRADE, L. LÓPEZ-GRIEGO, R. HERNÁNDEZ-FERNÁNDEZ and M.I. LÓPEZVILLASEÑOR, Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones
Biomédicas, UNAM, México.
Trichomonas vaginalis is a parasitic amitochondriate protozoa, etiological agent of human trichomonosis.
Phylogenetic analyses based on rRNA sequences place this organism among the earlier eukaryotic
branches. Our group has been interested in the polyadenylation process in T. vaginalis. By in silico
analysis of the 3' region of several genes, we have proposed the motif UAAA as the polyadenylation
signal, which is located 11-30 nucleotides upstream from the cleavage site. This motif has been found to
be generally coupled to the stop codon UAA. Moreover, the consensus sequence Y!(A) 0–3AAUU has
been proposed as the cleavage site and U-rich regions also are proposed to be located downstream from
the cleavage site. In this work, we performed a functional analysis of the putative polyadenylation signal
using a T. vaginalis transient expression vector, which contained the chloramphenicol acetyl-transferase
(CAT) reporter gene flanked by 5' and 3' regulatory regions from a T. vaginalis actin gene. By sitedirected mutagenesis, we introduced mutations in the polyadenylation and cleavage signals. The effect of
these mutations was evaluated by the biochemical activity of the reporter protein and by determining the
polyadenylation site of the mutant mRNA by 3' RACE. Our data confirm that the polyadenylation signal
in T. vaginalis is the tetranucleotide UAAA since the modification of any of these bases is reflected in a
decrease of the activity of CAT compared with the parental vector. Moreover, the polyadenylation of
these mRNAs is deficient and erratic. On the other hand, the proposed minimum signal for the cleavage
of the primary transcript (Y!;AAUU) was evaluated as well. These results will be presented and discussed.
207
Insights in DNA Repair and Homologous Recombination in Entamoeba histolytica: Characterization of
the EhRAD51 Recombinase. M. LÓPEZ-CASAMICHANA, C. LÓPEZ-CAMARILLO*, Posgrado en
Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, México DF, L.A. MARCHAT,
Programa Institucional de Biomedicina Molecular, ENMyH-IPN, México DF, and E. OROZCO,
Departamento de Patología Experimental, CINVESTAV-IPN, México.
To study the recombinational DNA repair in E. histolytica, we surveyed the parasite genome and identified a set of predicted genes involved in DNA double-strand breaks (DSBs) repair by homologous
recombination. These genes include homologous of yeast RAD52 epistasis group genes (MRE11,
RAD50, NBS1, RAD51, RAD51-C, RAD52, RAD54, RAD54B and RAD59), suggesting that E.
histolytica is skilled to perform homologous recombination. Then, we induced DSBs in E. histolytica by
UV-C irradiation. DNA damage was evaluated by TUNEL assays. By using a human γH2AX antibody,
we found that E. histolytica H2AX histone was phosphorylated 10 min after UV-C irradiation. These
results indicate that DSBs have been generated and early EhH2AX and chromatin modifications occurred when cells were exposed to UV-C. By RT-PCR assays, we showed that E. histolytica homologous
RAD52 epistasis genes were expressed differentially at different times after UV irradiation. Then, we
focused on the characterization of the putative EhRAD51 recombinase of E. histolytica, which has a
similar architecture and phylogenetic relationships to eukaryotic RAD51 family members. Interestingly,
Ehrad51 mRNA was expressed only after UV-C treatment, and transcript levels were increased during S
phase of cell cycle. In WB assays, anti-EhRAD51 antibodies detected EhRAD51 30 min after UV-C.
Intriguingly, anti-rEhRAD51 antibodies detected a 41 kDa protein in cytoplasm and a 46 kDa polypeptide in both nuclear and cytoplasmic fractions that may possibly result from post-translational modifications of EhRAD51. By laser confocal microscopy, EhRAD51 was detected in nuclear foci-like structures
in trophozoites submitted to UV-C. By biochemical studies, we showed that purified rEhRAD51
exhibits single- and double-stranded DNA binding, as well as DNA pairing and exchange between
homologous strands activities in vitro. These findings allow us to conclude that E. histolytica EhRAD51 is
a bonafide recombinase able to catalyze DNA paring and exchange between homologous strands.
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208
Entamoeba histolytica Dead-box RNA Helicases Family and Characterization of EhDEAD1, a Conserved RNA Helicase with ATPase and ATP-dependent RNA Unwinding Activities. C. LÓPEZCAMARILLO*, Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México,
México DF, M. GARCÍA HERNÁNDEZ, Norris Comprehensive Cancer Center, Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles CA, USA, L.A.
MARCHAT, Programa Institucional de Biomedicina Molecular, ENMyH-IPN, México DF, J.P. LUNAARIAS, Departamento de Biología Celular, CINVESTAV-IPN, México DF, and E. OROZCO, Departamento de Patología Experimental, CINVESTAV-IPN, México DF, México.
RNA helicases catalyze the unwinding of double-stranded RNA structures to perform numerous genetic
processes. Taking advantage of the completion of E. histolytica genome sequence, the protozoan responsible for human amoebiasis, we have performed a genomic survey. We identified 27 EhDEAD and 14
EhDExH-box putative RNA helicases, which contain almost all the conserved helicase motifs. By
phylogenetic studies and sequences comparisons, we detected paralogous proteins that resulted from
gene duplication. In addition, mutation events led to the formation of an unusually high number of
introns and the loss of some helicase motifs in some paralogous genes. Interestingly, two EhDexh genes
seem to be formed by gene fusion of two ancestral bacterial genes. Microarrays data analysis showed that
a large subset of EhDead and EhDexh genes is transcribed under diverse experimental conditions. Here,
we also report the cloning, expression and functional characterization of EhDEAD1, the first RNA
helicase studied in E. histolytica. EhDEAD1 is evolutionary related to yeast DED1 and human DDX3X
RNA helicases, both involved in translation and cell cycle regulation. The EhDEAD1 predicted amino
acid sequence exhibits the nine conserved motifs described for the DEAD-box SFII superfamily members. Interestingly, the endogenous EhDead1 mRNA is shorter than the predicted full length gene,
producing a protein that is smaller than expected. Purified recombinant EhDEAD1 protein presented
ATPase activity and was able to unwind RNA in an ATPase-dependant manner. EhDead1 gene is overtranscribed in the cell cycle S phase, suggesting a role of EhDEAD1 protein during cell cycle. Moreover,
in vivo inhibition of EhDead1 gene expression by antisense RNA stimulated cell cycle progression.
Intriguingly, in spite of the high sequence homology with yeast DED1, EhDEAD1 was unable to rescue
two yeast Ded1 RNA helicase mutants affected in translation. Our results strongly suggest that
EhDEAD1 is a functional RNA helicases that seems to function in cell cycle regulation.
209
Identification of Peptide Sequences Related to Apicomplexan Proteins from Sarcocystis neurona. J.W.
CAMP*, Department of Comparative Pathobiology, Purdue University, West Lafayette IN, K.
KOWALSKI, Bindley Bioscience Center Proteomics Facility, Purdue University, West Lafayette IN, and
S. DANGOUDOUBIYAM, Department of Comparative Pathobiology, Purdue University, West Lafayette
IN, USA.
Equine protozoal myeloencephalitis (EPM) is an equine neurologic disease caused by Sarcocystis neurona.
Horses are aberrant hosts in which the parasites can migrate to and infect the CNS after ingesting the
infective sporocyst stage. In some horses, the immune system fails to clear the infection, and nervous
system problems can develop that may lead to recumbency and death. Numerous non-specific neurologic
clinical signs are associated with EPM, making it difficult to diagnose. The current methods of diagnosis
(e.g., Western Blot identification of parasite-specific antibodies) can be inaccurate due to contamination
with blood and/or false positive reactions. Hence, new diagnostic techniques based on other horse and/
or parasite proteins may help to circumvent the problems associated with current techniques. As a first
step, identification and characterization of S. neurona proteins may provide information that can lead to
the development of new diagnostic techniques that utilize the parasite proteins as diagnostic biomarkers
for EPM-positive horse cerebrospinal fluid (CSF). We used two-dimensional electrophoresis and matrixassisted laser desorption ionization-time of flight (MALDI-ToF) ToF mass spectrometry to identify
several proteins from S. neurona based on comparative peptide homology with other apicomplexan
proteins. One of the S. neurona proteins identified was actin based on its peptide homology with actin
from Toxoplasma gondii. Other proteins identified were a hypothetical Plasmodium sp. protein, apical
membrane antigen 1 (Plasmodium yoelii yoelii), and immunoglobulin heavy chain binding protein (Eime146
ABSTRACTS
ria tenella). Characterization of these proteins indicates a biochemical similarity of S. neurona proteins
with other apicomplexan parasites, including the tissue-cyst forming T. gondii, which also causes encephalitis. Future studies will be undertaken to characterize additional S. neurona proteins. For example,
a western blot will be run using antiserum from an EPM-positive horse to probe for proteins of interest.
210
Differential Gene Expression Profiles in Taenia solium Cysticerci Obtained from Different Anatomical
Regions of Infected Pigs. A. GONZÁLEZ, E.L. SCIUTTO*, Instituto de Investigaciones Biomedicas,
UNAM, Ciudad Universitaria, México DF, R.J. BOBES, Instituto de Investigaciones Biomedicas, UNAM,
Ciudad Universitaria, México DF, I. ESTRADA, Escuela Nacional de Ciencias Biológicas, IPN, México
DF, and G. FRAGOSO, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México
DF, México.
Human neurocysticercosis (NC) can cause mild or severe neurological symptoms or be completely
asymptomatic. This heterogeneity may depend on host and/or parasite factors. Taenia solium is a parasite
of humans and pigs. Its larvae (cysticercus) lodge in the brain, causing NC, and in other tissues like
skeletal muscle and subcutaneous space, causing extraneuronal cysticercosis. In humans, NC may be
clinically heterogeneous, ranging from asymptomatic to severely incapacitating and even fatal presentation. The possibility that genetic differences between the parasites could contribute to the NC heterogeneity seems hardly difficult since high similarities were determined between parasites collected from same
geographic regions by RAPIDs.Thus, this study was designed to identify differences on the expression
profiles between parasites from the same individual that could account for the NC heterogeneity. The
gene expression profile of cysticerci from skeletal muscle (SM), subarachnoid space (SA) or parenchyma
(PA) of the same infected pig with an identical DNA, according to RAPIDs, was analyzed by differential
display PCR. mRNA was screened with one anchoring and four amplification probes. Differential gene
expression was found between cysticerci located in the different compartments. Greater differences
between the expression profiles were found between cysticerci located in muscles and in the CNS.
Sixteen cDNA fragments were displayed differentially for cysticerci located in the SA, 13 in the PA and
only three in SM. The results obtained in this study are the first experimental evidence that support the
possibility that parasite factors could be involved in the different clinical manifestation of human cysticercosis.
211
Cloning, Expression and Purification of EhADH243, a Polypeptide Involved in Entamoeba histolytica
Virulence. S. CASTELLANOS-CASTRO*, Patología Experimetal,CINVESTAV, México DF, C. BAÑUELOS,
Patología Experimental,CINVESTAV, México DF, M. MARTÍNEZ, Posgrado en Ciencias, Genóminas,
UACM, México DF, C. MARTÍNEZ-LÓPEZ, Estudios de Posgrado, DACS, Universidad Juárez Autónoma
de Tabasco, Villa Hermosa, Tabasco, and E. OROZCO, Patología Experimetal,CINVESTAV, México DF,
México.
Entamoeba histolytica is the protozoan causative of human amoebiasis. EhCPADH is a complex involved
in trophozoite virulence and is formed by a cysteine protease (EhCP112) and an adhesin (EhADH112).
EhADH112 is located at the amoeba plasma membrane and in vacuoles, and participates in adherence to
target cells and phagocytosis. EhADH112 is similar to mammalian ALIX and yeast BRO1 proteins,
which are conserved along the evolutionary scale and possess a structural architecture for multiple
functions. At their amino-terminus, these proteins contain a Bro1 domain and a consensus sequence for
Src-tyrosine kinase phosphorylation, both involved in signal transduction. Towards the carboxy-terminus, some of these proteins have a proline-rich domain for protein interaction. EhADH112, however,
has an adhesion epitope instead the proline-rich domain. A recombinant polypeptide, which contains the
last 243 residues of EhADH112 (EhADH243), inhibits RBC adherence and phagocytosis as well as the
destruction of MDCK monolayers. Moreover, hamsters immunized with EhADH243 were protected
against liver abscess formation after challenge with virulent trophozoites. In this work, we used
EhADH243 to produce polyclonal antibodies in rabbit (anti-EhADH243). In total extracts of E.
histolytica, these antibodies recognized a 78 kDa protein, which corresponds to EhADH112. By confocal
microscopy, anti-EhADH243 antibodies confirmed the presence of EhADH112 in the surface of nonpermeabilized trophozoites, but also in cytoplasmic vacuoles in permeabilized ones. Additionally, the
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EhADH243 encoding sequence was cloned in the pGEX-6P-1 prokaryotic expression vector in order to
generate a GST fusion protein (EhADH243-GST) that was solubilized and purified in native conditions
to perform in vitro protein–protein interaction assays. The EhADH243-GST purified polypeptide also
was recognized by the anti-EhADH243 antibodies and work, currently in progress, will determine
trophozoite proteins interacting with the last 243 residues of EhADH112.
212
Association of NRAMP1 Gene and Tnf-α Promoter Polymorphisms in Leishmaniasis. A. ORTÍZ-FLORES,
Depto. Biol. Mol. Histocompatibilidad, Hospital General Dr. Manuel Gea González, SSA, México
DF, G. DE LA ROSA, S. CHAVEZ-LÓPEZ, Depto. Parasitología Instituto de Diagnóstico y Referencia
Epidemiológicos, J. PASTOR-SANTIAGO, Programa de Control de Enfermedades Transmitidas por
Vector, SSA, Tuxtla Gutiérrez, Chiapas, C. GUZMÁN-BRACHO, Depto. Parasitología Instituto de
Diagnóstico y Referencia Epidemiológicos, V. MARTÍNEZ-VILCHIS, Depto. Biol. Mol. Histocompatibilidad, Hospital General Dr. Manuel Gea González, SSA, México DF, and A. OLIVO-DIAZ*, Depto. Biol.
Mol. Histocompatibilidad, Hospital General Dr. Manuel Gea González, SSA, México DF, México.
Leishmania is an intracellular parasite affecting mononuclear-phagocyte cells; protective immune response
is generated when macrophage is activated by interferon-γ and tumor necrosis factor (TNF)-α.Thirteen
polymorphic loci have been described in TNF-α promoter gene; the most studied in infectious diseases
are -308 and -238, and are related with susceptibility to leprosy, severe malaria, mucocutaneous leishmaniasis, and weakly with visceral leishmaniasis (LV). On the other hand, natural resistance-associated
macrophage protein 1 (NRAMP1) regulates macrophage activation and have multiple pleiotropic effects,
including regulation of TNF-α, MHC-class II molecules, nitric oxide release and L-arginine flux. It is a
proton/bivalent cation antiporter localized in the membranes of late endosomal and lysosomal compartments. In humans, 12 polymorphisms of NRAMP1 gene have been described, founding association of
some of them with leprosy, tuberculosis and malaria. We evaluate the allele association of –238 and –308
loci of TNF-α promoter and 274C/T, 1465-85G/A and A318V of NRAMP1 gene in 78 localized
cutaneous leishmaniasis (LCL) and 15 LV patients, compared with 127 and 90 controls from the
endemic areas of Pichucalco and Tuxtla Gutierrez, Chiapas, México, respectively. In the TNF-α promoter,
we found the genotype TNF-G/G associated with resistance to LCL (Odds ratio (OR) = 0.18 [confidence interval (CI) = 0.02–1.68]; p = 0.01; preventive fraction (PF) = 0.80), as well as allele TNF-G
(OR = 0.18 [CI = 0.02–1.70]; p = 0.01; PF = 0.80). In the NRAMP1 gene, genotype 274C/T2/2 is
associated with susceptibility to LCL (OR = 2.7 [CI = 1.4-5.0]; p = 0.003; EF = 0.25), while allele
1465-85G/A-1 is associated with protection to VL (OR = 0.42 [CI = 0.16-1.03]; p = 0.02; PF =
0.26). The latter suggests that there are two sites in the NRAMP1 protein that have functional implications in the efficient resolution of the disease and operate in an inverse way in LCL and LV. (This study
was partially supported by CONACyT I30103-B.)
213
The Expression of the Trichomonas vaginalis tvcp12 Cysteine Proteinase Is Regulated by the IRE/IRP
System. C.D. LEÓN-SICAIROS*, A.L. GUTIÉRREZ-ESCOLANO and R. ARROYO, Depto. Patología
Experimental, CINVESTAV-IPN, México DF, México.
Iron is an essential nutrient for growth, metabolism and expression of virulence factors in Trichomonas
vaginalis. The molecular mechanisms controlling the expression of some of these factors, however,
remain to be discovered. The tvcp12 gene encodes for one of the cysteine proteinases of the 30 kDa
region involved in cytoadherence. This gene is regulated negatively at the transcription level by iron. Our
goal was to identify the mechanism of iron regulation in the tvcp12 gene expression. By Western blot and
immunocytochemical assays using parasites grown in low- and high-iron conditions, we found that the
negative iron regulation of tvcp12 also was observed at the protein level. To determine the level of tvcp12
iron regulation, we analyzed the tvcp12 mRNA stability by RT-PCR assays after actinomicyn D-induced
transcriptional blockage, in parasites grown in low- and high-iron conditions. Interestingly, we found
that the tvcp12 mRNA is less stable in high- than in low-iron conditions, suggesting that the tvcp12 iron
regulation is at the post-transcriptional level. To identify whether a mechanism of iron regulation is
mediated by an IRE/IRP system, we searched for stem-loop structures, iron responsive elements (IRE),
in the 3´untranslated region (UTR) of the tvcp12 mRNA, using the mfold Zuker program. Predictions
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showed one hairpin structure in the 19-nt tvcp12 3´UTR. The interaction of the IRE-like structure with
cellular proteins was determined in vitro by RNA gel-shifting and cross-linking assays, using the tvcp12
IRE-like transcript and HeLa cells (positive control) or T. vaginalis cytoplasmic extracts. The specificity
of the RNA-protein complexes (IRE/IRP-like) formed between the tvcp12 transcript and both cytoplasmic extracts was confirmed using unlabeled homologous and heterologous RNAs as competitors. These
data suggest that the iron regulation mechanism of tvcp12 is mediated by an IRE/IRP-like system, similar
to the mechanism controlling the cellular iron homeostasis.
214
Identification of the Cysteine Proteinase TVCP4 of Trichomonas vaginalis. E. SOLANO-GONZÁLEZ*,
Depto. Biotecnología, CINVESTAV-IPN, México DF, L. ÁVILA-GONZÁLEZ, Depto. Patología Experimental, CINVESTAV-IPN, México DF, J. ORTEGA-LÓPEZ, Depto. Biotecnología, CINVESTAV-IPN,
México DF, and R. ARROYO, Depto. Patología Experimental, CINVESTAV-IPN, México DF, México.
Trichomonas vaginalis is the causative agent of trichomonosis, one of the most common sexually transmitted disease in humans. This protozoan has multiple proteinases, mainly of the cysteine (CP) type. Some
CPs involved in the trichomonal virulence are regulated by iron, which is an essential nutrient for
trichomonal growth, metabolism and virulence. TVCP4 is one of the CPs that induces apoptosis in host
cells. The size and iron effect in this proteinase, however, are still unknown. Thus, the goal of this work
was to obtain specific polyclonal antibodies against a synthetic peptide from the most divergent region of
TVCP4. The tvcp4 is 915 bp long and encodes for a 33.6 kDa papain-like CP precursor. To search for the
most divergent region of TVCP4, a multiple alignment between the deduced TVCP4 amino acid
sequence and the reported trichomonad CPs was performed. Based on the Kyte-Doolittle and HoppWoods scale, we looked for the predicted potentially antigenic and hydrophilic regions of TVCP4.
Moreover, the selected peptide DVSKGYAKVT (189–199 aa residues) was located on the surface of a
theoretical 3-D structure of TVCP4 obtained by homology modeling. The synthetic peptide was coupled
to 8-MAP and used to immunize five male Balb-c mice to produce the monospecific anti-TVCP4 antibodies. Dot-blot assays showed that the anti-TVCP4 antibody reacted with the synthetic peptide and
with trichomonad extracts. Western blot assays over nitrocellulose membranes containing total parasite
extracts showed that the anti-TVCP4 antibody reacted with a ~30 kDa protein band that was more than
three-fold more intense in parasites grown in iron-rich than in iron-depleted medium, as compared with
the anti-tubulin antibody used as a quantity control. These differences in the expression of TVCP4
suggest that this CP is positively regulated by iron.
215
IRP-like Proteins in Trichomonas vaginalis. J.C. TORRES-ROMERO* and R. ARROYO, Depto. Patología
Experimental, CINVESTAV-IPN, México.
Trichomonas vaginalis is a parasitic protozoan responsible for trichomonlasis. This protozoan has high
iron-dependency, favoring its growth and multiplication in culture. Iron also regulates some of the
trichomonal virulence properties by unknown mechanisms. In mammals, the iron homeostasis is regulated mainly at the post-transcriptional level by an IRE/IRP system. This mechanism involves the
binding of iron regulatory proteins (IRP1 and IRP2) to hairpin-loop structures, termed iron-responsive
elements (IREs), contained in the untranslated regions (UTR’s) of target mRNAs. Based on the IRElike hairpin-loop structures found in mRNAs of the differentially-iron regulated TVCP4 and TVCP12
cysteine proteinases (CPs), the goal of this work was to identify IRP-like proteins in T. vaginalis. To
determine the size of the trichomonad IRP-like proteins, nitrocellulose membranes containing cytoplasmic extracts of T. vaginalis were incubated with biotin-labeled human ferritin-IRE (IRE-fer) and TVCP4
IRE-like transcripts (Northwestern); or with specific antibodies to IRP1 and IRP2 (Western blot). In
addition, an RNA-affinity coprecipitation assay (pull-down) with trichomonad cytoplasmic extracts,
biotin-labeled IRE-fer, and streptavidin-agarose beads was carried out. A 60-kDa band was detected in
cytoplasmic extracts of T. vaginalis by Northwestern, Western blot and pull-down assays. These data
suggest that this 60 kDa protein may correspond to a T. vaginalis IRP-like protein.
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216
The Pyruvate Ferredoxin Oxido-reductase A (PFOR A) Is Located on the Surface of T. vaginalis Grown
in High-iron Conditions. P. MEZA-CERVANTEZ*, Depto. Patología Experimental, CINVESTAV-IPN,
México DF, M.E. ALVAREZ-SÁNCHEZ, Posgrado en Ciencias Genómicas, Universidad Autónoma de la
Ciudad de México, México DF, and R. ARROYO, Depto. Patología Experimental, CINVESTAV-IPN,
México DF, México.
Trichomonas vaginalis cytoadherence is a multifactorial process where parasite adhesins and environmental
factors like iron participate. At least five adhesins have been identified and characterized in trichomonads.
The expression of these adhesins is regulated by iron at the transcriptional and translational levels. Three
adhesins showed homology to host and parasite metabolic enzymes; while the AP120 adhesin only
showed homology with a parasite enzyme, the pyruvate: ferredoxin oxido-reductase A (PFOR A). This
enzyme has been located on the hydrogenosome membrane. The AP120 adhesin is expressed and
localized only on the parasite surface in high-iron conditions. To demonstrate that the surface-located
PFOR A behaves as the AP120 adhesin, the goal of this work was to localize specifically PFOR A in
parasites grown in different iron concentrations. To produce a mouse polyclonal antibody specific for
PFOR A and use it to localize PFOR A in trichomonads, we searched for the most divergent region of
PFOR A among the PFOR-like genes in the T. vaginalis genome project. The antigenicity of the selected
peptide (879–892 aa residues) was predicted by the Hopp-Woods scale program. Also, this peptide was
located on the surface of a theoretical 3-D structure of PFOR A obtained by homology modeling. Then,
the peptide was synthesized and coupled to 8-MAP, and used as antigen. By Western blot analysis, the
anti-PFORApep antibody reacted with the 50 kDa recombinant COO-terminal region of PFOR A,
previously obtained, and with a 120 kDa protein in iron-rich parasite extracts. Immunofluorescence
experiments showed that PFOR A is localized on the surface of fixed non-permeabilized iron-rich
parasites. These results strongly suggest that the surface-located PFOR A may participate in trichomonal
adherence as the AP120 adhesin.
217
The Legumain-like tvlegu-1 Cysteine Proteinase Is Anchored by Glycosylphosphatidylinositol on the
Surface of Trichomonas vaginalis. F.J. RENDÓN-GANDARILLA*, Depto. Patología Experimental,
CINVESTAV-IPN, México DF, N.A. RODRÍGUEZ-CABRERA, Depto. de Biotecnología, CINVESTAV-IPN,
México DF, J. ORTEGA-LÓPEZ, Depto. Biotecnología, CINVESTAV-IPN, México DF, and R. ARROYO,
Depto. Patología Experimental, CINVESTAV-IPN, México DF, México.
The tvlegu-1 is one of the 10 legumain-like CP genes identified in the T. vaginalis genome project. The
tvlegu-1 is 1167 bp long, and encodes a precursor protein of ~42.8 kDa. An antibody against a synthetic
peptide, specific for TVLEGU-1, reacted with the surface of iron-rich trichomonads, and recognized 60,
50 and 30 kDa protein bands in extracts from parasites grown in distinct iron concentrations, by Western
blot. Moreover, the expression of TVLEGU-1 is positively-regulated by iron at the transcription and
translation levels. Since no putative transmembranal domains were found in TVLEGU-1, the goal of this
work was to determine whether TVLEGU-1 is anchored by glycosylphosphatidylinositol (GPI) on the
trichomonad plasma membrane, and if is able to interact with the surface of HeLa cell. To detect the
presence of GPI-anchor in TVLEGU-1, live parasites grown in low- and high-iron conditions were
treated with phospholipase C (PLPC), and the supernatants were concentrated and analyzed by Western
blot assays. Two protein bands of ~57 and ~47 kDa were detected in the supernatants with the antiTVLEGU-1 antibody. These bands were more intense in the supernatant from parasites grown in highthan in low-iron conditions. In addition, we cloned, expressed and purified the recombinant TVLEGU-1
precursor to check its affinity to the surface of HeLa cells and to obtain polyclonal antibodies. By
immunofluorescence, these antibodies recognized with greater intensity the surface of control untreated
than PLPC-treated parasites. In addition, the recombinant TVLEGU-1 protein bound to the surface of
fixed HeLa cells. These data show that the TVLEGU-1 protein is located on the T. vaginalis surface by a
GPI anchor, and is one of the CPs of the 30 kDa region that may participate in cytoadherence.
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218
Circumsporozoite Gene Polymorphism among Plasmodium vivax Vk210 and Vk247 Parasite Phenotypes Isolated from Southern México. L. GONZÁLEZ-CERÓN, C. MONTERO-SOLÍS* and F.
SANTILLA-VALENZUELA, Parasitology Department, Regional Center for Public Health Research-INSP,
Tapachula, Chiapas, México.
In México, Plasmodium vivax is the primary agent of malaria, producing 98% of the total cases. Two P.
vivax variants were identified based on the central repeat units of the circumsporozoite (CS) proteins: the
VK210 [GDRA(A/D)GQPA] and K247 (ANGAGNQPG) phenotypes. For the CS-Vk210 protein of
salivary glands sporozoites from mosquitoes, variable molecular weights were encountered, but so far
nothing is known about P. vivax gene/protein diversity in Mexican isolates. To investigate CSP genetic
variation, it is of extreme importance to carry out phylogenetic analysis, strain identification and vaccine
development. P. vivax genomic DNA was obtained from the infected blood of patients from the Tapachula municipality, Chiapas. The DNA fragments from 5´-terminal up to region II (≈ 740–953 bp) of
the CSP gene were amplified, cloned and sequenced. The alignments and comparison were performed
using the BLASTN Ver. 2.2.1 and the CLUSTALW Ver. 3.2. programs. The 5´-region of either Vk210
or Vk247 parasites had limited polymorphism. For the central repeat region, parasites-Vk210 showed a
variation of 20, 17 and 11 repeat units of 27 nucleotides with high nucleotide polymorphism, while all
parasites-Vk247 showed conserved 18 repeat units. The 3r-region was polymorphic in length and
nucleotide variation: in parasites-Vk247, the amino acid sequence GAGGQAAGGNAANKKAGD was
repeated twice, similarly to an Iran isolate. The phylogenetic analysis based on the 3r region suggested
that parasites-Vk210 with 11 y 17 repeats are more related to parasites-Vk247: they expressed the amino
acid sequence GAGGQAAGGNAANKKAEDA, the same reported for parasites-Vk210 from India. The
parasites-Vk210 of 20 repeats were related to parasites from Central America. The comparison of the
CSP gene among Mexican and to worldwide P. vivax isolates and the biological relevance of the polymorphism will be discussed.
219
Structural and Functional Characterization of the URE1-binding Protein of Entamoeba histolytica. M.
CALIXTO-GÀLVEZ*, M. ROMERO-DÍAZ and M.A. RODRÍGUEZ-RODRÍGUEZ, Depto. Patologia
Experimental, CINVESTAV-IPN, Mèxico DF, Mèxico.
E. histolytica is a protozoan that has many unusual characteristics with regard to its transcriptional
control. Despite the importance of this mechanism, relatively little is known about the molecular factors
that drive this process in this parasite. The structural and functional analyses of the regulatory regions
responsible for transcription of the EhrabB gene showed a 13 bp fragment (-428 to -415) that was able
to drive efficiently the gene transcription. This fragment contains a motif similar to the URE1, motif
described as a transcriptional activator of hgl5 gene. In this work, we have initiated analyses of the
protein that binds to URE1 (EhURE1BP). We identified a protein of 95.6 kDa that binds to the URE1
motif. This protein contains a SNase domain, Tudor motif and one nuclear localization signal;
EhURE1BP presents a 23% identity with the co-activator transcriptional p100. The EhURE1BP
encoding gene was cloned in the pGEX-6P-1 vector and the recombinant protein was expressed and
purified. This protein was able of bind to the URE1 sequence. Currently, further investigations are in
progress to determine how this protein interacts with the EhrabB gene promoter.
220
Identification and Functional Characterization of the Activator Region of the EhrabB Gene Promoter of
Entamoeba histolytica. M. ROMERO-DÍAZ*, Departamento de Patología Experimental, CINVESTAVIPN, México DF, C. GÓMEZ, Programa Institucional de Biomedicina Molecular, ENMyH-IPN, México
DF, E. OROZCO and M.A. RODRÍGUEZ, Departamento de Patología Experimental, CINVESTAV-IPN,
México DF, México.
EhrabB is an Entamoeba histolytica gene encoding a Rab GTPase involved in phagocytosis. This gene is
situated at 332 bp upstream, but in the complementary strand, the gene encoding the EhCP112 polypeptide also is involved in E. histolytica pathogenesis. This genomic organization suggests that transcription regulatory elements of both genes may be shared or overlapped and, therefore, they may have a
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coordinated expression regulation. Here we carried out the identification and functional characterization
of the activator region of the EhrabB gene promoter to clarify the molecular mechanisms controlling the
EhrabB gene constitutive expression. We cloned into the promoter-less vector pBS-CAT-ACT DNA
fragments comprising nucleotides from -683 to +96, then we analyzed the ability of this to drive the
expression of the cat reporter gene on transfected trophozoites. A fragment from -428 to +24 with
respect to the first transcription initiation site of the EhrabB gene was able to drive efficiently the expression of the chloramphenicol acetyltransferase (CAT) reporter gene. We identified in this fragment a 13
bp motif that activates EhrabB transcription; it is 81.8% identical to the URE1 motif described as a
transcriptional activator of hgl5 gene. Finally, we detected three proteins of 79.1, 44.56 and 20.4 kDa
that bind to the URE1-like motif. Currently, further investigations are in progress to determining the
identity of these nuclear factors.
221
Molecular Confirmation of Taenia solium Isolates from Southern México. G.R. HERNÁNDEZCISNEROS*, R.D. RODRÍGUEZ-CANUL, J.A. PÉREZ-VEGA, Laboratorio de Inmunologia y Biología
Molecular, CINVESTAV-IPN, Unidad Mérida, Mérida, Yucatán, México, H. YAMASAKI, Department of
Parasitology, Asahikawa Medical Collegue, Midorigaoka Higashi, Asahikawa, Japan, F. CEN-AGUILAR,
Departamento de Investigación, Mérida, México, J.C. ALLAN, Pfizer Animal Health, Pfizer Limited,
Sandwich, Kent, U.K, and P.S. CRAIG, Cestode Zoonoses Research Group, University of Salford,
Salford, U.K.
As part of a comprehensive study on epidemiology on Taenia solium taeniasis/cysticercosis in the Yucatán
state of México, fecal samples of 4,847 individuals from six rural communities were tested for T. solium
by ELISA-coproantigen and microscopy. From those individuals, 75 persons tested positive to Taenia
spp. eggs and proglottides. After treatment with 2 g of niclosamide and purged with Epson salt and
Magnesium milk, 57 (1.17%) individuals expelled Taenia spp. proglottides. Some of the proglottides
were kept in sterile PBS implemented with antibiotics, and others were fixed in 70% ethanol. In the
laboratory, all proglottides were checked for taxonomical features and DNA was extracted to perform a
multiplex PCR (specific to Taenia solium, T. saginata and T. asiatica). DNA from proglottides of T.
solium, T. saginata and T. asiatica were used as controls. All taxonomical features of the recovered material
from the field resembled T. solium and these findings were confirmed with a multiplex PCR, which
showed a band of 429 pb to 453 pb specific to T. solium American type. The results of this study give
evidence of T. saginata (the beef tapeworm). If this is the case, the scheme of control in southern México
can be done as in Asian countries, where T. saginata is not endemic.
222
Genotyping Giardia intestinalis in México: Where Is Genotype B? F. VARGAS-PUERTO*, R. MOOPUC, V. SUÁREZ-SOLÍS, Unidad Interinstitucional de Investigación Clínica y Epidemiológica, Facultad
de Medicina, UADY/Instituto Mexicano del Seguro Social, Mérida, Yucatán, R. REYES, Centro de
Control Canino, Mérida, Yucatán, and R. CEDILLO-RIVERA, Unidad Interinstitucional de Investigación
Clínica y Epidemiológica, Facultad de Medicina, UADY/Instituto Mexicano del Seguro Social, Mérida,
Yucatán, México.
Giardia intestinalis (syn. Giardia lamblia, Giardia duodenalis) is a protozoan parasite that can infect the
intestinal tract of many animal species. Currently, several genotypes from this parasite have been identified. Genotypes A and B infect humans and other mammals and could produce different clinical manifestations. There are genotypes that have been isolated only from animals: C and D (dogs), E (livestock), F
(cat) and G (rodents); for this reason, the carrying genotype of animals could have zoonotic importance.
Objective: Determine the prevalent genotypes of G. intestinalis in humans and dogs in Mérida, Yucatán,
México. Material and Methods: Samples of faeces from humans with cysts of G. intestinalis were processed to extract and purify DNA. A fragment of glutamate dehydrogenase GDH) gene was amplified by
PCR using specific primers. The PCR product was digested with restriction enzymes Apa1 and BspH1
and analysed by RFLP with the aim to differentiate genotype A from B. Trophozoites from dogs were
obtained directly from the duodenum after they were euthanized at the Center for canine control. A
fragment of GDH gene was amplified by PCR and the obtained product was sequenced Results: DNA
was extracted, purified and amplified from 49 samples from faeces from humans. The pattern of RFLP
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of all samples was characteristic of genotype A. The sequence of the PCR product of GDH gene from
one dog had 100% identity with genotype A (Gene Bank Database). Discussion: In several studies of
genotyping in México from humans and dogs, including the current study, only genotype A has been
identified.This is contrary to reports from United States, Europe, Asia and Australia, where genotype B
is identified frequently. Dogs in Mérida carrying genotype A have a zoonotic potential.
223
Initial Characterization of the Putative Polyadenylation and Transcriptional Factor EhPC4 of Entamoeba
histolytica. O.N. HERNÁNDEZ DE LA CRUZ*, Posgrado en Ciencias Genómicas, UNAM, L.A.
MARCHAT, Programa Institucional de Biomedicina Molecular, E, E. OROZCO, Departamento de
Patología Experimental, CINVESTAV-IPN, and C. LÓPEZ-CAMARILLO, Posgrado en Ciencias Genómicas, UNAM, México.
In E. histolytica, the causal agent of human amoebiasis, mechanisms regulating gene transcription and
mRNA processing are poorly understood. We initiated a study of factors involved in the regulation of
mRNA transcription and its processing in this organism. Previously, we have reported the pre-mRNA
cleavage/polyadenylation machinery in E. histolytica, and interestingly, many of their elements are highly
conserved when compared with their human and yeast homologous. Here, by in silico analysis of the E.
histolytica genome, we detected a sequence that codifies for a putative protein homologous to human
PC4 (Sub1 in S. cerevisiae) that we designated as EhPC4. The predicted EhPC4 protein exhibits a high
similarity and identity to the proteins PC4 (65 and 61%, respectively) and SUB1 (44 and 40%, respectively). PC4 and SUB1 are abundant multifunctional proteins that play diverse roles in cellular processes,
including transcription, polyadenylation, DNA replication and repair, and chromatin organization in
human and yeast. Here, we focused in the characterization of EhPC4 protein. Ehpc4 is a 477 bp intronless gene that predicts a putative protein of 151 amino acids (18 kDa). Notably, EhPC4 sequence
presents 48% of Glu and Lys amino acids residues. It also presents two ssDNA-binding and transcriptional activation PC4 domains at the C-terminal; and a lysine/glutamic acid-rich region at the N-terminus. Human PC4 functions are regulated by phosphorylation. Interestingly, EhPC4 exhibits some
putative Ser/Glu phosphorylation sites at the N-terminus. By RT-PCR assays, we detected the expression
of Ehpc4 mRNA in the different cell cycle phases of synchronized trophozoites. Then, we cloned the
Ehpc4 gene in the pRSET-A expression vector and expressed the EhPC4 recombinant protein (rEhPC4).
Subsequently, we purified the rEhPC4 by Ni-NTA affinity chromatography and inoculated rabbits to
generate specific polyclonal antibodies. By laser confocal microscopy, and using the anti-EhPC4 antibodies, we localized the endogenous EhPC4 protein mainly in the nuclei of permebilized trophozoites.
224
Identification of the Poly (A) Ribonucleases Family in Entamoeba histolytica and Initial Characterization
of the EhCAF1 Deadenylase. I. LÓPEZ-ROSAS*, Posgrado en Ciencias Genómicas, Universidad
Autónoma de la Ciudad de México, México DF, B. GALLO, Programa Institucional de Biomedicina
Molecular, ENMyH-IPN, México DF, C. LÓPEZ-CAMARILLO, Posgrado en Ciencias Genómicas,
Universidad Autónoma de la Ciudad de México, México DF, E. OROZCO, Deparatmento de Patología
Experimental, CINVESTAV-IPN, México DF, and L.A. MARCHAT, Programa Institucional de Biomedicina Molecular, ENMyH-IPN, México DF, México.
Polyadenylated mRNA turnover is a critical event in eukaryotic gene expression. The main mRNA
degradation pathway is initiated by poly(A) tail shortening, followed by 5´ end decapping. Deadenylation is performed by CAF1/POP2 and CCR4 deadenylases in yeast and human. In addition CAF1/POP2
and CCR4 proteins have been involved in transcription, cell cycle and DNA repair processes. In E.
histolytica, the protozoan parasite responsible for human amoebiasis, little is known about mRNA
metabolism. To initiate the study of mechanisms involved in mRNA degradation, we performed a
genomic survey and identifed a set of putative poly(A) ribonucleases in E. histolytica, including homologous proteins to human and yeast CAF1, CAF1-like, and CCR4 proteins. By RT-PCR assays, we showed
that EhCaf1, EhCaf1-like and EhCcr4 genes were expressed differentially after DNA damage and heat
shock treatments. Then, we focused on the characterization of EhCAF1 protein. Predicted amino acids
sequence of EhCAF1 showed a similar organization reported for eukaryotic CAF1 deadenylases, including the conserved ribonuclease DEDD motif and a RNA-binding domain. By phylogenetic analysis
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using Neighbor joining method, we showed that EhCAF1 is related phylogenetically to eukaryotic
ribonucleases. Then, we cloned the Ehcaf1 gene and expressed the recombinant EhCAF1 protein
(rEhCAF1) in E. coli as a 6 x His-tagged fusion protein. rEhCAF1 was purified using Ni-NTA column
and was inoculated in rabbits to generate specific polyclonal antibodies. In WB assays, using protein
extracts of E. histolytica trophozoites, anti-EhCAF1 antibodies recognized a band of 37 kDa. By laser
confocal microscopy, anti-EhCAF1 antibodies recognized abundantly the endogenous EhCAF1 protein
in cytoplasm and, to lesser extent, in nuclei of permeabilized cells. Finally, biochemical studies showed
that rEhCAF1 exhibits RNA binding activity in vitro. Deadenylation assays and in vivo studies in progress
could help us to define the role of EhCAF1 in the mRNA degradation and its contribution in the gene
expression regulation in E. histolytica.
225
Position Effects at Telomeres that Control VAR Gene Regulation in Plasmodium falciparum. R.
HERNÁNDEZ-RIVAS, Departamento de Biomedicina Molecular, CINVESTAV-IPN, México DF, México,
and A. SCHERF*, Biology of Host–Parasite Interaction Unit, Institut Pasteur, Paris, France.
Plasmodium falciparum parasites use antigenic variation to avoid immune clearance and increase chronic
infection in the human host. Variation at the surface of parasitized red blood cells is mediated by a family
of surface antigens encoded by var genes. Mono-allelic activation of a single member of the var gene
family is controlled by a number of different epigenetic factors such as reversible chromatin changes at
promoter regions and nuclear relocation of the active var gene. Var genes are silenced at the nuclear
periphery, a zone generally characterized by heterochromatin. Activation of a var gene, however, occurs
in a particular perinuclear area, which remains elusive. P. falciparum chromosome ends play a particular
role in reversible var gene silencing. Telomeres anchor chromosome ends to the nuclear periphery and
recruit proteins that apparently facilitate spreading of compact chromatin into telomeric var genes
leading to gene repression (called “Telomere Position Effect,” TPE). A search for candidate genes
involved in perinuclear heterochromatin formation and TPE has identified several proteins that accumulate in the nuclear periphery and co-localize with chromosome ends. Gel shift and chromatin immunoprecipation (ChIP) analysis demonstrated the specific interaction of PfSir2 and two other proteins
named PfTelBP2 and PfTelBP3 with telomere repeats and adjacent Telomere Associated Repetitive
Elements (TARE). At truncated chromosomes (complete deletion of TAREs), PfSir2 does not spread
into the telomere-adjacent coding region, demonstrating that TAREs (in particular Rep20) act as cisacting sequences required for TPE in P. falciparum.
226
Immunization with TcSPA::TcHsp70ATP AND TcSPA::TcHsp70CHP RECOMBINANTE PROTEINS
PARTIALLY PROTECT AGAINST ACUTE PHASE OF CHAGAS’ DISEASE IN THE MOUSE MODEL. B.
SALGADO-JIMÉNEZ*, L, BAYLÓN PACHECO, P. TALAMÁS-ROHANA and J.L. ROSALES-ENCINA,
Departamento de Patología Experimental, Cinvestav-IPN, México DF, México.
Protection studies have been carried out in animal models immunized with different antigens and DNA.
We have found a 50% decrease of parasitaemia in mice immunized with the gene TcSP, and 100%
survival of these animals compared with control (50% survival) when infected with trypomastigotes,
Thus, vaccination with the gene TcSP protects animals against acute and chronic stages of the disease.
Because DNA vaccination is still not approved by WHO, we propose the use of Heat shock protein
(Hsp)-fused antigens as an alternative to vaccination studies, since it has been demonstrated that Hsp70
proteins are able to induce the production of antigen-specific TCD8+/antibodies to the Hsp70-associated antigen. To study the immune response induced by the TcSP recombinant protein, a DNA fragment
coding for the NH2-terminal part (473 aa) of the TcSP protein (812 aa) was fused with the DNA
fragments coding for the ATP binding domain and Chaperon domain of the TcHsp70 gene. These
chimeric DNA molecules were subcloned in prokariotic expression plasmids, which allowed the purification of his-tagged TcSPA::TcHsp70ATP and TcSPA::TcHsp70CHP recombinant proteins. BALB/c mice
were immunized with these recombinant proteins and then challenged with blood-form trypomastigotes.
Parasitaemia levels were measured at different times post-infection, and it was detected that
TcSPA::TcHsp70ATP recombinant protein induced a 20% parasitaemia decrease, whereas
TcSPA::TcHsp70CHP recombinant protein induced a 33% parasitaemia decrease. These results indicate
154
ABSTRACTS
that TcHsp70Chaperon-associated antigen is a better immunogen than TcHsp70ATP-associated antigen
for induction of protection in mice experimental model.
227
Gene Targeting and Biochemical Characterization of Clan SB and SC Serine Proteases in Leishmania
spp. R.K. SWENERTON*, B.L. KELLY, M. SAJID and J.H. McKERROW, Sandler Center for Basic Research in Parasitic Diseases, University of California, San Francisco CA, USA.
Serine proteases have been implicated in key stages of the infectious lifecycle of kinetoplastid parasites.
Treatment of Leishmania donovani with the broad serine protease inhibitor, Pefabloc, arrested replication
in vitro. More than 20 distinct serine protease genes can be identified in the published L. major genome.
Our initial biochemical and proteomics studies of L. donovani and L. major extracts confirmed the
presence of an active clan SC protease, oligopeptidase B (OpdB). Previous work in other trypanosomatids has shown that this subfamily of enzymes plays a role in host-cell invasion and contributes to
the pathogenesis of disease. We have begun functional characterization of this protease and recently
deleted it by gene targeting. Phenotypic analysis of these knockouts is underway. We also have cloned the
OpdB gene and added reporter- and epitope-tags for localization and overexpression in L. donovani.
Additionally, we have identified a L. donovani clan SB subtilisin. This enzyme has been deleted by gene
targeting and knockout parasites are currently under phenotypic analysis. Initial investigations suggest
that these latter mutant parasites have impaired promastigote to amastigote differentiation axenically. The
L. donovani and L. major subtilisin genes have been cloned also and are currently being recombinantly
overexpressed for biochemical analysis.
228
Variation of Onchocerca volvulus Mexican Isolates. A. MONROY-OSTRIA*, A. RAMIREZ-RAMIREZ and
S. GONZÁLEZ-GUZMÁN, Departamento de Inmunologia, Escuela Nacional de Ciencias Biologicas,
IPN, México DF, México.
Onchocerciasis is the world’s second leading infectious cause of blindness. It is endemic to Africa, the
Arabian Peninsula, and the Americas. Around 120 million people world-wide are at risk of onchocerciasis. DNA from Onchocerca volvulus from Oaxaca and Chiapas, México were used as templates to amplify
and sequencing members of the O-150 Onchocerca Onchocerca specific repeat sequence family. The
amplicons were cloning with TA Cloning (pCRR II Vector) (Invitrogen, USA) and transformed into E.
coli INV αF´. and sequenced by using the kit (ABI PRISM Dye Terminator Cyclers Secuencing Ready
Reaction Kit, Perkin Elmer) and an automated sequencer Abi Prism M 310 Genetic Analizer, Perkin
Elmer. The sequences were edited with DNAMAN; Chromas Ver. 2.0 and Seaview. Multiple sequence
alignment was carried out using Clustal-X Ver. 1.83. Phylogenetic trees were constructed by the neighbour-joining method. Evolutionary distances were calculated using a Kimura’s two-parameter method
with MEGA Ver. 3.1. program. Sequences data were compared with previously published sequences of
O-150 Onchocerca-specific repeat sequence family. The O-150 sequences were compared with the O-150
sequences from samples from Africa, Guatemala and Brazil. Higher variation in the Mexican isolates
sequences were found than in the Brazilian and African, and Mexican isolates are more related to the
Guatemala isolates. (A. Monroy-Ostria is supported by COFAA and EDI, IPN, México; S. GonzálezsGuzman and A. Ramírez-Ramírez were sponsored by CONACyT, México.)
229
Detection of Toxoplasma gondii by Coproparasitoscopic ELISA in Blood Serum PCR and in Feces of
Artificially Inoculated Cats. N. CÁRCAMO-ARÉCHIGA*, S.M. GAXIOLA-CAMACHO and J.J.
PORTILLO-LOERA, Area de Parasitología, FMVZ-UAS, Culiacán, Sinaloa, México.
To determine the sensibility and specificity of the coproparasitoscopic of flotation technique and PCR in
comparison with ELISA technique (inmunoenzimatic Trial) in blood serum for the detection Toxoplasma
gondii in oocysts from feces of cats inoculated artificially, 30 adult cats were used distributed in two
groups, with the following processing. Group 1: 15 cats inoculated oral way with 1.5 mL of a mixture of
conservation with middle of cell cultivation that contained a minimum of 1,500 taquizoytes of Toxoplasma gondii; Group 2: 15 cats not inoculated (control). of each group were taken 70 samples for the
coproparasitoscopic of flotation analysis and for the cell extraction to analyze by PCR, and 70 samples of
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ABSTRACTS
serum for ELISA IgG and IgM. The cats inoculated turned out to be positive to the tests of coproparasitoscopic of flotation and ELISA IgG and IgM, while the of the group control resulted negatives to all
the tests. The sensibility for the comparation between coproparasitoscopic technique and ELISA IgG
was 84.2%, specificity 88.9%, positive predictive value and negative predictive value 80 and 91.4%, false
positive proportion 11.1%, false negatives 15.8, with an accuracy of 87.3% and an index J of Youden of
7, LR (+) 7.58 y LR (-) 0.18 and the values of sensibility of 86.5%, specificity 89.0%, positive predictive value and negative, false negatives proportion and false positive and accuracy they were of 80 and
92.9%, 11 and 13.5% and 88.2% respectively, with an index J of Youden of 0.8, LR (+) 7.9 y LR (-)
0.15 for ELISA IgM. It is concluded that the utilization of the coproparasitoscópica of flotation technique in comparison with ELISA is adequate for the diagnosis of Toxoplasma gondii in cats, when this is
found in the phase of oocysts excretion. In the samples of feces the amplification of the DNA was not
achieved of T. gondii by PCR.
230
Cryptosporidium in Oysters Sold in México City’s Popular Markets and Commercial Centres. O.
VÁZQUEZ-TSUJI*, Laboratorio de Biología Molecular y Microscopía Electrónica, Facultad Mexicana de
Medicina, Universidad La Salle, T. CAMPOS-RIVERA, Servicio de Parasitología y Micología Instituto
Nacional de Pediatría México, A. RONDÁN-ZÁRATE, Laboratorio de Biología Molecular y Microscopía
Electrónica, Facultad Mexicana de Medicina, Universidad La Salle, M. PONCE-MACOTELA, M.
MARTÍNEZ-GORDILLO, Instituto Nacional de Pediatría, México, M. GUTIÉRREZ-QUIRÓZ, UNAM,
and D. ZARAGOZA-ALVAREZ, Instituto Nacional de Pediatría, México.
Objective: To determinate the frequency of Cryptosporidium contamination in oysters sold in México
City’s popular markets and commercial centers by performing molecular characterization on Cryptosporidium in oysters. Methods: A comparative studied was performed from July, 2005 to January 2006; a
sample of 355 specimens of Crassostrea virginica from 71 popular markets and commercial centres of 13
political delegations in México City was studied by microscopy and PCR. Results: From a total sample,
44.33% were positive for Cryptosporidium sp. cysts in Crassostrea virginica. By PCR, a 825 base pair (bp)
product was obtained in the control samples (Cryptosporidium parvum), and in oyster samples, products
were 500 bp, 650 bp and 825 bp. Conclusion: Oysters could be concentrating resistant parasite structures in water contaminated with fecal material. Morphologic identification of species required molecular
techniques, and the small PCR product allows speculation that the oysters are contaminated by other
Apicomplexa species phylogenetically close to Cryptosporidium.
231
Temporal Dynamics of Parasitic Mite Aggregation (Acarophenax tribolii) on Red Flour Beetle Populations (Tribolium castaneum). T.J. DOBRZENIECKI* and J.E. LÓPEZ, Biology Department, Grand Valley
State University, Allendale MI, USA.
The distribution of parasites on hosts, usually aggregated, plays important roles in the demography,
ecology and coevolution of parasites and hosts. Parasite distribution in populations can be very dynamic.
Parasites in a single-host population may be aggregated, overdispersed or randomly distributed at
different times, or the degree of aggregation may increase and decrease over time. Parasite distribution
may reach a stable equilibrium point, a stable cycle, or show other dynamic properties. The temporal
dynamics of aggregation in most host–parasite systems is not well documented. This experiment describes the temporal dynamics of the distribution of Acarophenax tribolii, an ectoparasitic mite, on
Tribolium castaneum, the red flour beetle. Flour beetle populations were infected with A. tribolii and data
on their distribution at 2, 4, 8, and 16 weeks after infection were collected. The number of mites on each
beetle was counted and the parasite distribution quantified using mean crowding and the variance to
mean ratio. The study also considered the effect of host population size on the dynamics of parasite
aggregation. Preliminary results show both temporal variation in parasite aggregation, and a significant
effect of host population size on parasite aggregation. More detailed results will be presented and discussed.
156
ABSTRACTS
232
Local Adaptation for Virulence of the Ectoparasitic Mite Acarophenax tribolii on Red Flour Beetles
(Tribolium castaneum). K.L. KOLAR*, G.K. DUNLEAVY and J.E. LÓPEZ, Biology Department, Grand
Valley State University, Allendale MI, USA.
When parasites infect a new host population, their virulence often changes. Some times, virulence
increases (e.g., HIV in humans). Because of local adaptation, however, some parasites are better adapted
to and have higher fitness when infecting their native host. Locally adapted parasites should be less fit in
new hosts, less able to infect successfully and reproduce, and therefore less virulent. We tested these
alternative expectations using transplant experiment. We moved Acarophenax tribolii mites from a flour
beetle Tribolium castaneum population, to which they had adapted for at least 400 generations, to new
beetle populations collected from various geographic locations, and measured their virulence. Since A.
tribolii does not cause host mortality, we used parasite prevalence and the slope of regressions of host
fecundity on mite load as measures of virulence. Since the effect of parasites on fecundity depends on
parasite load, the slope of the regression between the two is an estimate of the per capita effect of mites
on beetle fecundity, which can be interpreted as per capita parasite virulence. Our data showed the
expected negative correlation between host fecundity and parasite load, but our sample did not allow
robust conclusions about local adaptation in A. tribolii based on the slope of the regressions. When we
used parasite prevalence as a measure of virulence, we also did not find evidence of local adaptation.
There was no correlation between parasite prevalence and the geographic distance between the original
and new host populations.
233
Prevalence and Transovarial Transmission of Trypanosomatid in the Insect Host Cyrtomenus bergi
Froeschner (Hemiptera: Cydnidae). A.M. CAICEDO*, Universidad del Valle, Postgrado Ciencias
Biologìa, Cali, Valle del Cauca, Colombia, G. GALLEGO, Centro Internacional de Agricultura Tropical,
CIAT, Unidad de Biodiversidad, Cali, Valle del Cauca, Colombia, G.A. TORRES, Universidad del
Cauca, Departamento de Ciencias, Popayàn, Cauca, Colombia, J.E. MUÑOZ, Universidad Nacional de
Colombia, Sede Palmira, Biologìa Molecular, Palmira, Valle del Cauca, Colombia, and J. MONTOYALERMA, Universidad del Valle, Facultad de Ciencias Naturales y Exactas, Cali, Valle del Cauca, Colombia.
Cyrtomenus bergi, a burrowing bug, affects a variety of tropical crops, causing economical losses in
Colombia as well as in others neotropical countries. Recently, it has being found harboring an unknown
trypanosomatid species in its salivary glands, haemocel and digestive tract. Prevalence, biological characteristics and the possibility of vertical transmission of C. bergi’s symbiont were studied by standard
microscopy and PCR techniques. Wild bugs collected from Pereira (Risaralda–Colombian department)
and reared bugs were examined. Haemolymph and intestine content of 30 individuals per stage (eggs,
nymphs and adults) from each population were suspended on 100 µl of PBS and smeared on a microscope slide and examined under a Nikon Microphot DIC and phase-contrast microscopy. Furthermore,
DNA extraction from each sample was done according to Westenberger et al. (2004) to perform PCR.
In order to determine transovarial transmission, 50 pairs of adult bugs were kept in laboratory trays until
eggs and viable offspring were obtained during two generations. Thirty individuals per stage (eggs,
nymphs and adults) were examined, as mentioned above. The 5S and Spliced Leader RNA genes were
amplified from about 10 ng of genomic DNA following protocols described by Dollet et al. (2000).
Both strands are underway to be sequenced. All samples were positive for trypanosomatids. Also, after
three generations, DNA was detected in all examined samples, allowing for the first time the conclusion
of the existence of transovarial transmission in trypanosomatid species. Parasites ranged from long to
short forms and cyst stages varied in numbers in the different stages of C. bergi. Long forms, in which
bodies are elongated and twisted, predominate mainly in the fifth instars and adults. The remainded
instars, short forms, either with long or short flagellum or without flagellum, were the most abundant
and frequent. Heavy infections were detected in nymphs (fifth) and adult stages from both populations.
Their numbers, counted in haemolymph pool of three adults, fluctuated from 34,750 to 232,500
trypanosomatid/ml.
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234
Amoebic Liver Abscess Regeneration after Treatment with Metronidazole. M. SÁNCHEZ-PALOMERO*,
Department of Experimental Pathology, CINVESTAV-IPN, México DF, R. GAXIOLA-CENTENO, Laboratory Animal Facilities, CINVESTAV-IPN, México DF, V. TSUTSUMI and M. SHIBAYAMA, Department of
Experimental Pathology, CINVESTAV-IPN, México DF, México.
Amoebic liver abscess (ALA) is a common extraintestinal complication produced by the protozoan
Entamoeba histolytica. Susceptible rodents, such as hamsters and gerbils, have been used frequently for the
experimental production of ALA and the establishment of host cellular processes occurring during the
hepatic infection by the parasite. On the other hand, it is well known that healing of ALA after an
adequate and opportune treatment occurs without formation of scar tissue. ALA size reduces gradually
after metronidazole treatment, leaving only very few signs of organ collapse. As a result, liver regeneration in ALA after treatment has been considered as an optimal process occurring in the hepatic parenchyma, contrary to the frequently distorted liver healing observed in other hepatic pathologies, where
eventually the organ terminates in an irreversible fibrosis or cihrrosis. Currently, we studied the cellular
events occurring during the resolution of experimental ALA in hamsters treated with metronidazole.
Male adult hamsters of seven to eight weeks old, weighing approximately 100 g, were intrahepatically
inoculated with 1 x 106 E. histolytica trophozoites. ALA progression was left for three days (~25% of
lesion) before metronidazole treatment was started. A dose of 5 mg/100 g body weight was intraperitoneally injected every other day, for a total of 11 applications. Groups of eight hamsters each were sacrificed at different times post-treatment. Livers were dissected and processed for conventional paraffin
embedding for histology. Light microscopy analysis showed that the process ALA healing goes along
with a chronic inflammatory reaction with abundant foamy macrophages and gradual involution of
granulomas, presence of neoformed blood vessels and hepatocyte and bile ducts proliferation. Although
the role of foamy macrophages in the optimal healing of liver damage is suggested, a further knowledge
on the molecular mechanisms involved in hepatic regeneration is required and experiments currently are
being carried out in our laboratory.
235
Presence of Gastrointestinal Helminths in the Antillean Manatee (Trichechus manatus manatus) from
the State of Tabasco, México. A. HERNÁNDEZ-OLASCOAGA*, Departamento de Parasitología,
División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Villahermosa,
Tabasco, L.D. OLIVERA-GOMEZ, Conservación de Fauna Acuática, División Académica de Ciencias
Biológicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, and J.L. DOMINGUEZALPIZAR, Área de Salud, Escuela Superior de Ciencias Agropecuarias, Universidad Autónoma de
Campeche, Campeche, México.
Studies on parasite fauna of American sirenians is scarce. For the Antillean manatee (Trichechus manatus
manatus), which is considered a threatened subspecies all along its distribution range, just five species of
helminths parasites have been registered: (Chiorchis fabaceus, C. groschafti, Cochleotrema cochleotrema,
Moniligerum blairi and Heterocheilus tunicatus). To contribute to knowledge on parasite diversity on this
subspecies, 16 fecal samples, obtained from eight localities in the Mexican state of Tabasco (a hotspot of
manatee distribution in México) were analyzed by direct, spontaneous coproparasitologic sedimentation
(formalin–ether and warm water) and flotation (saline saturated and sacarose saturated solutions)
techniques in search of parasite eggs. Eleven samples (68.7%) were positive to the presence of at least
one species of helminth. Eggs of seven species of gastrointestinal parasites were found: two trematodes
(C. fabaceus and M. blairi), four nematodes (H. tunicatus, Contracaecum sp., Anisakis sp. and Ascaridae)
and one acanthocephalus (unidentified). The efficacy of the different techniques was observed; formaline-ether was the technique that allowed the largest number of species (six) to be registered, and it also
registered the largest percentage of samples with parasites.
236
Characterization of Vesicles with Fibrilar Content Present in Entamoeba histolytica Trophozoites
Recovered from Experimental Liver Abscess. N. SEGOVIA-GAMBOA*, Departamento de Patología
Experimental, CINVESTAV-IPN, Y. MEDINA-FLORES, INDRE, L. PÉREZ-CASTILLO, A. ANGEL, V.
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ABSTRACTS
HERNÁNDEZ-RAMÍREZ, B. CHÁVE-MUNGUÍA, A. MARTÍNEZ-PALOMO and P. TALAMÁS-ROHANA,
Departamento de Patología Experimental, CINVESTAV-IPN, México.
Entamoeba histolytica cysts, the infective stage of the parasite, have been poorly studied. E. invadens, a
reptile parasite that presents striking similarities with E. histolytica, has been used as model to study
encystation, due to the ease of inducing this process in axenic culture. Trophozoites, the vegetative phase
of the life cycle, produce damage when they are inoculated in the liver of experimental animals, similar to
that produced in humans. E. histolytica trophozoites recovered from experimental liver abscess showed,
by electron microscopy, the presence of vesicles with a characteristic fibrilar content. Their aspect and
consistency was similar to that present in encystations vesicles described in E. invadens and other parasites
such as Giardia and Acanthamoeba. It has been described that host–parasite interaction may modulate
gene expression and function, therefore, the aim of this work was to characterize these vesicles using the
B4F2 MAb that strongly recognizes the wall of E. invadens cysts. E. histolytica trophozoites were inoculated in the hamster liver, and parasites were recovered at different times post-infection and used when
they reached the first logarithmic phase of growth. Cells recovered at 72 h post-infection showed a
higher number of these vesicles. The immunofluorescence staining pattern in recovered trophozoites
showed abundant inner vesicles, which co-localized with calcofluor positive vesicles. These vesicles were
absent in long-term cultured trophozoites. On the other hand, Western blot analysis showed the presence
of a 57 kDa protein present in total extracts and pellet fractions from recovered E. histolytica and E.
invadens cysts, respectively. This protein was not present in total extracts from long-term cultured trophozoites, confirming immunofluorescence findings. These results strongly suggest that host–parasite
interactions exerts a strong influence in the parasite phenotype, inducing the presence of these vesicles in
the trophozoites, whose biological function will have to be further explored.
237
Detection of Secretory and Cytosolic Phospholipase A2 in Macrophages Stimulated with Entamoeba
histolytica Soluble Proteins. B.E. SÁNCHEZ-RAMIREZ*, H. CHAPARRO-REYES, M.D. GONZÁLEZHORTA, Lab. Biotecnologia, Fac. Ciencias Quimicas, UACh, and P. TALAMÁS-ROHANA, Dept.
Patología Experimental, CINVESTAV-IPN, México.
An increase in plasmatic and hepatic levels of prostaglandin E2 (PGE2) during liver abscess development
is mediated by induction of cyclooxygenase-2 (COX-2) in macrophages (MOs) and polymorphonuclear
cells. Synthesis of PGE2 is regulated by activation of phospholipases A2 (PLA2), which catalyzes the
hydrolysis of the sn-2 ester bond of membrane phospholipids to release arachidonic acid (AA). PLA2
family comprises a cytosolic (cPLA2), secretory (sPLA2), and a Ca+2-independent group IV (iPLA2)
enzymes. The aim of this study was to analyze expression of sPLA2 and cPLA2 enzymes in MOs interacted with Entamoeba histolytica soluble protein. COX-2, sPLA2, and cPLA2 enzymes were detected by
using specific rabbit polyclonal antiserums and FITC-conjugated goat anti-rabbit IgG, in J774A.1 MOs
challenged with soluble amoebic protein (SAP; 30 µg/ml) for 0, 4, and 8 h. Lipopolysaccharide stimulated (LPS; 0.1 µg/ml) and non-stimulated MOs were used as positive and negative controls respectively.
Although LPS and SAP induced COX-2 in MOs at early (0 and 4 h), and delayed phase (8 h), fluorescence with SAP was more intense. Translocation of COX-2 from nuclear envelope to cytosol was evident
and an enzyme-aggregated pattern was observed at 8 h. Expression of cPLA2 in MOs stimulated with
LPS and SAP was demonstrated, mainly in cytosol, at 0 and 4 h, with a decrease at 8 h. Contrarily,
cytosolic expression of sPLA2 was higher at 0 and 8 h than at 4 h. The results demonstrate that SAP
induces cPLA2 and sPLA2 expression at early and delayed phase, respectively, suggesting that both
enzymes could provide AA to COX-2, which was continuously expressed in those times, to sustain PGE2
production.
238
Chronic Psychosocial Stress-induced Down-regulation of Immunity: The Effect of Isolation in a Murine
Model of Experimental Cysticercosis Infection. G. FRAGOSO, Instituto de Investigaciones Biomedicas,
UNAM, Ciudad Universitaria, México DF, L. MAYAGOITIA, Instituto Mexicano de Psiquiatrìa Dr.
Ramon de la Fuente, Departamento de Etologia, México DF, L. PAVON, E. CASTILLO, Instituto Mexicano de Psiquiatrìa Dr. Ramon de la Fuente, Departamento de Psicoinmunologia, México DF, B.
HERNÁNDEZ, Facultad de Medicina, UNAM, Ciudad Universitaria, México DF, M. MAÑON, E.L.
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SCIUTTO* and G. ROSAS, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria,
México DF, México.
Environmental or metabolic stress could greatly affect the homeostasis in humans and livestock promoting chronic inflammatory disease and infection. This is a longitudinal study designed to evaluate the
effect of chronic stress on the susceptibility and the specific immunity against the experimental murine
cysticercosis caused by Taenia crassiceps. These parameters were compared between two groups of mice:
one in which each male was maintained isolated in each house (high stress) and a second group in which
each male was maintained with two females per cage (low stress). The level of stress was established
according to the behavior and the adrenal weight of the mice. A transient decrease in the T cell proliferation was found increased in animals under stress. This immune imbalance promoted an increase in the
susceptibility to the parasitosis. These data support the relevance of stress in the pathophysiology of this
parasitic infection.
239
Life Cycle of Triatoma pallidipennis (Stall,1872) and Other Aspects about Its Biology. J. TAY*, Departamento de Microbiología y Parasitología, Facultad de Medicina, UNAM, México DF, J.T. SÁNCHEZVEGA, Unidad de Medicina Familiar, Coyoacán, Instituto Mexicano del Seguro Social, México DF, L.
CALDERÓN-ROMERO, Departamento de Microbiología y Parasitología, Facultad de Medicina,
UNAM, México DF, R. ROMERO-CABELLO, Hospital General de México, O.D, México DF, D. RUIZSÁNCHEZ and J.A. GARCÍA-TAY, Departamento de Microbiología y Parasitología, Facultad de Medicina, UNAM, México.
Arthropods are important as transmitters of diseases to men. Transcending of triatomines as transmitters
of Chagas disease has been established in Brazil since 1909 by Carlos Chagas. According to the PAHO
informs, in Latin America, there are about 100 million people exposed to the infection. Because of this,
it is fundamental to study triatomines in México to define the biological aspects related with its capacity
of transmit Trypanosome cruzi to humans. Triatoma pallidipennis male and female adults originally from
Tutuapan del Oro, State of México, were allowed to copulate in order to establish a colony in the insectary of the Microbiology and Parasitology Department of the Faculty of Medicine, National Autonomous
University of México. Its oviposition capacity under variable temperature and environmental humidity
was determinated counting by each female; the capacity of nymph and adults for feeding and defecating
over the host in order to define the potential of transmission of Trypanosome cruzi to humans and the
capacity of feeding over different mammals and birds, and other aspects of the triatomines biology was
pointed out, too. T. pallidipennis is capable of ingesting blood until six times its corporal weight during
the first nymph stage and until eight times its weight during the third stage, because they are considered
as one of the most effective transmitters of T. cruzi.
240
Relationship of FREPs to Acquired Resistance in the Snail Biomphalaria glabrata. B.A. STOUT*, S.
ZHANG, C.M. ADEMA and E.S. LOKER, Department of Biology, The University of New Mexico,
Albuquerque NM, USA.
Several digenetic trematode species use the freshwater snail Biomphalaria glabrata as an obligatory
intermediate host. Previous exposure to trematode parasites may lead to acquired resistance in B. glabrata. Previous observations that prior exposure to radiation-attenuated miracidia of Echinostoma paraensei yields experimental induction of acquired resistance in B. glabrata were confirmed, and the involvement of fibrinogen-related proteins (FREPs) as candidate factors in acquired resistance was investigated.
Snails were exposed to irradiated E. paraensei miracidia, and then challenged eight days later with normal
miracidia. Only 10–30% of snails previously exposed to irradiated miracidia became infected following
the challenge, compared to 80–90% of snails exposed only to normal miracidia. Quantitative PCR using
mRNA from whole snail bodies revealed different transcription profiles of FREPs between first response
and acquired resistance. First exposure to miracidia resulted in an upregulation of FREP2, but not 3, 4
or 7. Induction of acquired resistance was associated with increased amounts of transcripts of FREP2, 3,
4 and 7. Preliminary immunoblot analysis of snail hemolymph with antisera raised against recombinant
IgSF domains from FREP3 and 4 revealed the presence of FREP3 protein in two of three snails exhibiting acquired resistance. Only one of nine snails that were exposed to normal miracidia and became
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ABSTRACTS
infected had FREP3-immunoreactive hemolymph proteins. The protein expression of FREP4 was
variable between the test groups with no obvious pattern. These mRNA and protein results suggest that
FREPs3 and 7 may play a role in B. glabrata’s acquired resistance to E. paraensei. (Supported by NIH
RO1 AI24340.)
241
Boophilus microplus Tick-transmission of Two Different Mexican Anaplasma marginale Strains. R.
PÉREZ-MUNOZ*, Escuela de Medicina Veterinaria y Zootecnia, Benemerita Universidad Autónoma de
Puebla, N.N. MORA-CONTRERAS, Division de Ciencias Biologicas y de la Salud, Universidad Autónoma Metropolitana, E.E. ROJAS-RAMIREZ, M.A. GARCIA-ORTÍZ, J.F. PRECIADO-DE-LA-TORRE, R.
HERNÁNDEZ-ORTÍZ and S.D. RODRÍGUEZ, Centro Nacional de Investigaciones Disciplinarias en
Parasitologia Veterinaria, INIFAP, SAGARPA, México.
The cattle tick Boophilus microplus is considered the main vector of the rickettsia Anaplasma marginale in
México, yet it is known that not all Anaplasma strains are tick-transmissible. In the present study, two
Mexican Anaplasma strains with different degrees of virulence were tested for their ability to be transmitted by B. microplus ticks. For the present study, Yucatán (Y) and Aguascalientes (A) Anaplasma strains
and B. microplus Media Joya strain were used. Each rickettsial strain was inoculated, respectively, in male
ELISA and msp5 PCR-negative Bos taurus steers (1 and 2), which were used as infection donors. These
bovines were simultaneously and stepwise infested with 15-day-old B. microplus tick larvae. When the
bovines presented patent rickettsemia (5–10%), meta-larvae and meta-nymphs were collected and
incubated for approximately 48 hr at 27°C and 80% relative humidity and then infested on splenectomized susceptible bovines (four and five, for Y and seven and eight for A strains, respectively) as
nymphs, and unsexed young adults. Young male adults of each strain were transferred to susceptible
bovines (six and nine for Y and A, respectively) immediately after collection. A bovine was infested with
ticks fed on susceptible steers as control of infection. Transmission evaluation in the bovines was performed by rectal temperature, Giemsa-stained blood smear and hematocrit. Blood samples were analysed
by PCR specific for msp5 and the msp1α variable region. All bovines replicated A. marginale of the
corresponding strain. In contrast, the control bovine remained negative during the duration of the
observation period. B. microplus ticks were capable of intrastadial and interstadial transmission. (Work
funded by Mexican SAGARPA-CONACYT, Grant 2002-1212.)
242
Different Endocytic Pathways for Human Holo–transferrin and Holo-lactoferrin Proteins in Entamoeba
histolytica. M. REYES-LÓPEZ*, Depto. de Biologia Celular, CINVESTAV-IPN, México DF, N. LEÓNSICAIROS, Depto. Investigacion del Hospital Pediatrico de Sinaloa, Culiacan, Sinaloa, A. CANIZALEZROMAN, Depto. de Biologia Molecular del Laboratorio Estatal de Salud Publica, Culiacan, Sinaloa,
and M. DE LA GARZA, Depto. de Biologia Celular, CINVESTAV-IPN, México DF, México.
Holo-transferrin (holo-Tf) and holo-lactoferrin (holo-Lf) are mammalian host proteins found in serum
and secretions, respectively. They share 65% similarity and bind two atoms of ferric iron. Holo-Tf
delivers iron to all body cells, then all cells possess a Tf receptor. Holo-Lf captures iron in mucosal tissues
in order to avoid its availability to pathogens. These proteins, however, can be used as a source of iron
for growth by some pathogenic microorganisms, including the parasitic protozoan Entamoeba histolytica,
the causal agent of amoebiasis, which has developed strategies to scavenge iron from the human host. In
this work, we followed the endocytic pathway of FITC–lactoferrin and FITC-transferrin in amoebic
trophozoites, using specific antibodies to different vesicular structures: clathrin, caveloin, antigen-1 for
early endosomes, manose-6-phasphate receptor for late endosomes, and Lamp-1 for lysosomes, in
confocal microscopy assays. Holo-Tf was endocytosed through constitutive clathrin–coated vesicles,
whereas holo-Lf internalization required caveolae-like vesicles, which need induction to activate this
pathway. At different times, both molecules reached the endosomal–lysosomal route and were found in
neutral and acidic vesicles, where some cysteine protease activities cleaved these proteins in order to be
used by the parasite. Apparently, iron from holo-Tf was released in early endosomes, a less acidic compartment, and Lf, which shows higher affinity for iron than Tf, released iron inside lysosomes where pH
is acidic enough for this purpose. The differential internalization pathways for these two structurally
similar proteins could be due to the protein function or activity, depending on its iron saturation and
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ABSTRACTS
location in the body. Knowing the vesicular traffic of host iron-binding proteins allow us understand its
survival inside the host and the endocytic mechanisms in this primitive eukaryote with characteristics of a
higher cell.
243
Co-expression of the TVLEGU-1 of Trichomonas vaginalis with Chaperones Favors Its Expression in a
Soluble Fraction. R. ARROYO*, Departamento de Patología Experimental, CINVESTAV-IPN, México DF,
N.A. RODRÍGUEZ-CABRERA, Departamento de Biotecnología y Bioingeniería, CINVESTAV-IPN,
México DF, L. BRIEBA-DE CASTRO, Departamento de Bioquímica, CINVESTAV-IPN, México DF, and J.
ORTEGA-LÓPEZ, Departamento de Biotecnología y Bioingeniería, CINVESTAV-IPN, México DF,
México.
TVLEGU-1 is an asparaginyl endopeptidase, the first cysteine proteinase (CP) of clan CD identified in
the 30 kDa region involved in the Trichomonas vaginalis cytoadherence. As with other cysteine proteinases involved in Trichomonas vaginalis virulence, gene expression and proteolytic activity of TVLEGU-1 is
regulated by iron concentrations, suggesting that it may participate in parasite virulence. The aim of this
work was to express a soluble recombinant TVLEGU-1 in order to realize functional and structural
studies. The 1.167 kb ORF of the Tvlegu-1 gene was cloned into the pCold I expression vector, and
expressed in Escherichia coli. To obtain the recombinant protease in soluble form, we expressed the
TVLEGU-1 through the co-expression of pCold I vector and the chaperone team plasmids pG-Tf2,
pTf16, pGro7 and pKJE7. By SDS-PAGE and Western blot assays with TVLEGU-1 antibodies a 41 kDa
band of the recombinant TVLEGU-1 was found only in the insoluble fraction when E. coli was transformed by the pCold I construct alone. The co-expression with GroEL-GroES-Tig (pG-Tf2) as well as
with Tig (pTf16) did not improve the soluble expression of TVLEGU-1. Interestingly, the co-expresion
of TVLEGU-1 with chaperones GroEL-GroES (pGro7) and DnaK-DnaJ-GrpE (pKJE7) greatly improved the expression of TVLEGU-1 in soluble fraction.
244
Anti-trematode Parasite Responses of the Snail Biomphalaria glabrata: Architecture of FREP Loci. C.
LUN*, T.M. MADRID, B. HANELT and C.M. ADEMA, CETI, Department of Biology, The University of
New Mexico, Albuquerque NM, USA.
The snail Biomphalaria glabrata reacts to infection by digenetic trematodes with increased expression of
fibrinogen-related proteins (FREPs). FREPs are hypothesized to function in non-self recognition by
binding parasites and precipitating parasite-derived molecules. This response is interpreted as part of a
“best effort response” by the snail aimed at immuno-elimination of parasites, whether it ultimately results
in success or failure (in susceptible snails). FREPs are remarkably diverse; this probably increases the
non-self recognition repertoire. FREP genes are thought to diversify somatically by recombinatorial
processes and point mutations. To further understand the diversification mechanism, we investigated the
arrangement of FREP gene loci in the genome of B. glabrata. Southern analysis indicated that the B.
glabrata-derived genomic insert of bacterial artificial chromosome (BAC) clone 0125N01 contains
multiple FREP genes. Sequencing (subcloning and primer walking) revealed clustering of four FREP
genes within a ~120 kbp region of the B. glabrata genome. Surprisingly, two FREPs displayed identical
5' sequences, while the 3’ termini differed considerably. This pattern and the clustering of loci concords
with the notion that sequence exchanges may contribute to FREP diversity. Analysis of intergenic regions
of clustered FREP genes for consensus regulatory sequences may provide insights into the regulation of
transcription of FREPs. (Supported by NIH RO1 AI052363.)
245
Parasitologic and Ultrasonographic Study in Dogs and Sheep from a Community in the State of
México. U.G. RODRÍGUEZ, P.J. MARAVILLA-CAMPILLO*, A. GUTIÉRREZ, P. MATA, Hospital General
“Dr. Manuel Gea González,” SSA, México DF, J.J. MARTÍNEZ, Facultad de Medicina Veterinaria y
Zootecnia, UNAM, and ANA FLISSER, Facultad de Medicina, UNAM, México.
Human infections, especially with helminth parasites, are emerging health issues, as the human environment is increasingly shared with infected animals as pets, livestock and wildlife. In the present study, the
presence of intestinal worms in dogs and cystic echinococcosis in sheep was evaluated using Faust and
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ultrasonographic techniques, respectively, in animals from a community in the State of México with a
recent report of human echinococcosis. The faecal samples of dogs were collected by rectal spoon, while
sheep’s viscera were revised in vivo and diagnoses were confirmed during some necropsies. Additionally, a
questionnaire was given to owners of animals to learn some risk factors. From 414 canine faecal samples,
39% were positive, and helminth´s eggs founded were: Ancylostoma sp. (31%), Toxocara sp. (6%),
Capillaria sp. (0.4%), Trichuris sp. (0.2%) and Taenia sp. (1%); also, mixed parasitosis: Toxocara–
Ancylostoma (3%), Trichuris–Ancylostoma (0.2%) and Capillaria–Ancylostoma (0.2%). Dogs positive
for Taenia eggs were treated with prazicuantel and with a purge saline; the stools were recovered and
sieved. In all cases, exclusively T. pisiformis adults were obtained. Regarding cystic echinococcosis, 81% of
the sheep were examined by ultrasound and no bovine with hydatidic cysts were founded; this data was
corroborated during some necropsies. The questionnaire showed that of 446 houses, 42% had at least
one dog and 18% let their canines have access to the residence area. The majority of inhabitants in the
community identified the hydatidic cyst by pictures and expressed that this parasite is found sporadically
in livestock viscera. Although no animal with E. granulosus was found, other parasites, pathogens potentially identified such as Ancylostoma and Toxocara, were found, suggesting that it is necessary to apply
some control and preventive measures to avoid new cases of these parasites.
246
Dermatophagoides sp. Close to D. farinae Mites in Commercial Hens that Cause Dermatitis and Loss of
Feathers. M.T. QUINTERO-MARTÍNEZ*, Department of Parasitology Medicine, Faculty Veterinary and
Zootecnia, National University of México, I.G. JUÁREZ-VEGA, A. ELENO-VILLA, Department of
Parasitology Medicine Faculty Veterinary and Zootecnia, National University of México, and E.
PLASCENCIA, Laboratories LAPISA, Michoacán, México.
Mites similar to those present in dust can cause respiratory allergies in farm workers dedicated to breeding hens for commercialization, as well as feather loss and dermatitis in these birds. In Mexico, Dermatophagoides pteronyssinus, D. farinae and D. evansi have been identified. Looking for D. pteronyssinus in the
dust of houses in México City, Mayagoitia identified D. pteronyssinus-like mites. In addition, Quintero
identified D. evansi and D. pteronyssinus in chicken farms. Castillo Mares isolated D. pteronyssinus from the
coat and habitat of dogs, and Montaño found these mites in the coat and habitat of cats. Here we report
the association of dust mites and chickens in Colima State, México. Mite samples were collected directly
from fertile, egg-producing hens. Mites were clarified with Kono solution (PreHoyer), mounted on slides
using Hoyer liquid, and observed under a stereoscopic microscope. Aproximately 50 mites/slide were
counted. Mites of the Pyroglyphidae family and the Dermatophagoides genus were identified, and all
stages of the life cycle were found: egg-loaded females, larvae, and nymphs (protonymphs and tritonymphs). Determination of the species of Dermataphagoides in the chickens showed that these mites
share characteristic with D. farinae and D. microcera; also, chickens showed dermatitis and loss of feathers.
247
Actin Cytoskeleton of MDCK Cells Was Modified by Toxoplasma gondii. S. MUÑIZ-HERNÁNDEZ* and
M. MONDRAGÓN, Biochemistry Department, CINVESTAV-IPN, México DF, S. GONZÁLEZ, Electron
Microscopy Unit, CINVESTAV-IPN, México DF, and R. MONDRAGÓN, Biochemistry Department,
CINVESTAV-IPN, México DF, México.
Toxoplasma gondii is an obligatory intracellular parasite that invades a broad range of cells and tissues.
Intracellular location of T. gondii induces association of mitochondria and intermediate filaments of the
host cell with the parasitophorous vacuole; until now, the events that regulate such association are not
known.The objective of this study was to determine structural and functional changes in MDCK cells
during invasion and parasite proliferation. Effects of Toxoplasma invasion on cytoskeleton, intracelular
junctions and the cytoplasm of MDCK cells were studied and characterized by TEM, SEM and confocal
microscopy. Distribution of F actin was determined with fluorescent fallacidin as a marker for actin
filaments. In confluent cells, actin filaments were enriched at the baso-lateral membrane. A modification
at the baso-lateral membrane was detected mainly in the desmosomes area, with the formation of lateral
elongations of the plasmamembrane, which became interdigitated with those from the nearby cells. It
does not seem that tight junctions were modified due to the parasite invasion. In concluent cells, filopo163
ABSTRACTS
dia at the apical membrane were distributed, limiting the region of the intercellular junctions, leaving the
apical membrane absent of such structures. These results suggest that T. gondii induces a redistribution of
the actin filaments, according to the parasite intracellular development, in order to facilitate subsequent
invasions or the intracellular development of the parasites.
248
Parasitosis in Chaetognaths in the North of the Mexican Caribbean Sea. H. LOZANO-COBO*, M.
GOMEZ DEL PRADO-ROSAS, Laboratorio de Parasitologia, Departamento de Biologia Marina,
Autónoma de Baja California Sur, La Paz, B.C.S, J.N. ALVAREZ-CADENA and A.R. ALMARALMENDIVIL, Instituto de Ciencias del Mar y Limnologia, Estacion Puerto Morelos, UNAM, Cancun,
Quintana Roo, México.
Monthly studies of parasitism for the North of Quintana Roo, Mexican Caribbean Sea, were carried out
in Chaetognaths in relation to hydrology from January to December 2004. Flora, fauna and environmental conditions allowed to characterize three environments: lagoon, oceanic, and reef related; and two
seasons: dry and rain. Zooplankton organisms were collected with a conic net (mesh 330µ) and temperature (°C), salinity (ups) and Oxygen (mg/l) were measured in situ. A total of 17,825 chaetognaths were
captured, from those 1,153 were parasitized (4,214 parasites were obtained). Ferosagitta hispida was the
most abundant chaetognath and also the most parasitized. Trematode metacercariae of Hemiuridae were
the most abundant parasites obtained. Seasonally, parasitism was heavier in the dry season and lowest
during the rains. Parasitism was heavier in the lagoon environment in contrast with the oceanic and reef
areas where parasitism was lower. It is suggested that human settlements and a lengthy residence of the
lagoon waters (ca. 3 years) are the main causes of heavier parasitism.
249
Induction and Characterization of the Conoid Extrusion in Toxoplasma gondii Tachyzoites. M.
GONZÁLEZ-DEL CARMEN*, M. MONDRAGÓN, Department of Biochemistry, CINVESTAV, México
DF, S. GONZÁLEZ, Electron Microscopy Unit, CINVESTAV, México DF, I. GALVÁN, Electro Microscopy
Unit, CINVESTAV, México DF, México, and R. MONDRAGÓN, Department of Biochemistry,
CINVESTAV, México DF, México.
Toxoplasma gondii is an obligate intracellular protozoan parasite that infects humans and a broad variety
of animals. In immuncompromised individuals, it causes a severe disease and death. T. gondii is able to
invade all cells in the organism through calcium-dependent dynamic mechanisms such as gliding motility,
conoid extrusion and molecular secretion. Conoid is a highly dynamic structure located at the apical end
of the tachyzoites (the invasive form of T. gondii). Conoid is projected against the host cell plasma
membrane during the active invasion, a process called conoid extrusion. Previous studies demonstrated
that exposure of tachyzoites to ethanol induces calcium dependent events related to the active invasion
and microneme secretion (a type of secretory organelles of the parasite). In this study we characterized
the induction of the conoid extrusion by incubation with ethanol as a reversible effect without modifying
the viability nor the invasive capability of the tachyzoites. By using these experimental approaches, we
achieved a pharmacological characterization in order to know and to evaluate the role of different
signalling pathways. By using a broad variety of drug inhibitors, western blot analysis and subcellular
distribution by confocal microscopy, we could determine that induction of conoid extrusion involves
activation and participation of phospholiphase C and protein kinase C (PKC) within the parasite.
250
Survival of Mycobacterium tuberculosis H37Rv Inside Entamoeba histolytica Strain HM1:IMSS. G.G.
SÁNCHEZ-CAÑAS, Lab. Biotecnología, Fac. Ciencias Quimicas, Universidad Autónoma de Chihuahua,
F.J. SOLÍS-MARTÍNEZ, L.G. CORDOBA-FIERRO, J. CARRAZCO-PALAFOX, Fac. de Medicina, Universidad Autónoma de Chihuahua, B.E. SÁNCHEZ-RAMIREZ*, V. NEVAREZ-MOORILLON and B.E.
RIVERA-CHAVIRA, Lab. Biotecnologia, Fac. Ciencias Quimicas, Universidad Autónoma de Chihuahua,
Chihuahua, México.
Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis and considered a worldwide
health problem. A characteristic of the bacterial infection is the interference of the microorganism with
the immune response, since it survives inside human macrophages. The main problem is the lack of
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ABSTRACTS
phagosome acidification, and the obstruction of phagosome and lysosome union. Various mycobacteria
species persist inside free-living amoebae; however, there are no reports on the interaction with pathogenic species, such as Entamoeba histolytica.Therefore the aim of this work was to evaluate the interaction
of both pathogens, to better understand their mechanisms of action. M. tuberculosis H37Rv and E.
histolytica trophozoites were incubated in controlled conditions, in a 1:10 relationship (amoeba:bacteria)
and samples were taken at different interaction times (0, 0.5, 1, 2, 3, 5 and 10 min). Mycobacterial
survival assay was carried out by Alamar blue test, growth in MGIT medium and bacilloscopy. Amoeba
viability assay was carried by culturing amoebas in TYI-S33 medium and viability was determined by
tripan blue. At all interaction times, optic and electron microscopy samples were processed. Mycobacteria
did not survive at any time of interaction as demonstrated by no evidence of metabolic activity as no
growth on MGIT, and absence of bacilli by bacilloscopy. The amoeba survived, since recovered amoebas
grew under the same conditions as the control. In microscopy, extra and intracellular bacilli were observed at 0, 0.5 and 1 min. At 2, 5 and 10 min, bacilli were not observed. On the other hand, amoeba
presented numerous phagocytic vesicles. E. histolytica showed active phagocytosis, with evidence of
intracellular bacilli and its degradation. Results suggest that M. tuberculosis was unable to survive inside
E. histolytica, which was not affected by the mycobacteria.
251
Community Helminth Parasites of Freshwater Fishes of Baja California Sur, México. O. MÉNDEZ* and
G. SALGADO-MALDONADO, Departamento de Zoología, Instituto de Biología, México DF, México.
The majority of studies of helminth parasites of freshwater fishes in México have been made in the
Neotropical region, while a few studies have been done in the Nearctic region. Until now, this last region
has not been explored for that kind of studies. The geographical isolation of the Baja California peninsula, its aridity, its weather conditions (Guzmán-Poo, 2004), its ictiofaunistic composition and the spatial
distribution of this fauna (Ruiz-Campos et al, 2002) make an important situation for testing some
hypotheses about helminth parasites of freshwater fishes; this will be useful to verify if knowledge of the
subject about the Neotropical region can be applied to the Nearctic region of México. The aim of this
project is the study of communities of helminth parasites of freshwater fishes of Baja California Sur that
constitute a biogeography province Nearctic (Morrone, 2006). Over one year, fishes will be caught in
different localization in BCS with fish register using crest nets or line fishing according the area. The
recollect of helminth parasites will become at moment with a stereoscopic microscopic. Recovered
helminth will be fixing and conserve according to specific techniques by group. In the laboratory, the
helminth parasites will be dehydrated, dyed and mounted for the taxonomic composition according to
primary bibliography and data base containing all the records of helminth parasites of fresh water fishes
of México. To date, 2,231 helminth of five species have been examined (Neoechynorhynchus sp., Gyrodactylus sp., Centrocestus sp., Nematodo sp. and Trematodo sp.) in different fishes (Poecilia reticulata, Eleotris
picta, Tilapia cf. zilli and Dormitator latifrons) localized in San Jose del Cabo B.C.S. The acanthocephalans Neoechynorhynchus sp. represent the highest prevalence (100%) in Dormitator latifrons and the
metacercariae of genera Centrocestus (145.8 and 189.6, respectively) in Eleotris picta, a host with the
greater wealth of helmintos with tour species (Trematodo sp., Centrocestus sp., Neoechynorhynchus sp. and
Nematodo sp.).
252
Comparing in vitro Effects of Antibiotics, Anthelmintics and Antifungal Agents on the Removal of
Microsporidia, Heterosporis anguillarum, and Survival of Fish Cells. S.R. MONAGHAN*, Department of
Biology, Wilfrid Laurier University, Waterloo, Ontario, Canada, C. LO, Department of Zoology, National
Taiwan University, Taipei, Taiwan, Republic of China, N.C. BOLS, Department. of Biology, University of
Waterloo, Waterloo, Ontario, Canada, and L.E. LEE, Department of Biology, Wilfrid Laurier University,
Waterloo, Ontario, Canada.
The EP-1 cell line is a persistently infected epithelial cell line derived from Anguilla japonica (Japanese
eel) with the microsporidia Heterosporis anguillarum (Kou GH et al., 1995, Aquaculture 132:161-173).
H. anguillarum was formerly known as Pleistophora anguillarum, but molecular evidence justified its
transfer to the genus Heterosporis (Lom J et al., 2000, Dis. Aq. Org. 43:225-231). Microsporidia are
obligate intracellular organisms believed to be protozoans, but current molecular findings suggest they
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ABSTRACTS
might be closer to fungi, thus we have coined the term mycoprotozoan in reference to the microsporidia,
and hence antimycotic agents are being tested. Infection in A. japonica results in myositis and eventual
destruction of muscle tissue. This also has been observed recently in some fishes inhabiting the Great
Lakes for which the causative agent has been identified as H. anguillarum, leading to this parasite’s
recent inclusion as an emerging Aquatic Invasive Species in North America. Therefore, in vitro investigation of the host–pathogen relationship is necessary to clarify conditions influencing transmission, infectivity and survival. This is done using light, confocal, and electron microscopy to study the effects of
broad-spectrum antibiotics, anthelmintics and antifungal agents such as ciprofloxacin, norfloxacin,
ofloxacin, albendalzole and amphotericin on H. anguillarum infection.
253
Clinical Study of Dogs Naturally Infected with Trypanosoma cruzi in Mérida, Yucatán, México. J.V.
CRUZ-CHAN*, Laboratorio de Parasitología, CIR, Universidad Autónoma de Yucatán, Mérida,
Yucatán, M. BOLIO-GONZÁLEZ, R. COLÍN-FLORES, Facultad de Medicina Veterinaria y Zootecnia,
Universidad Autónoma de Yucatán, Mérida, Yucatán, M.J. RAMIREZ-SIERRA and E. DUMONTEIL,
Laboratorio de Parasitología, CIR, Universidad Autónoma de Yucatán, Mérida, Yucatán, México.
Chagas disease is a antropozoonosis widely distributed in the Americas, with 100 millions infected
people and 50,000 deaths every year. Lineage 1 of Trypanosoma cruzi predominates in México, Guatemala
and the northern part of South America (Colombia, Ecuador and Perú). However, in spite of a relatively
high prevalence of infection in dogs, little is known about the features of T. cruzi 1 infected dogs. In this
study, we compared clinical, parasitological and immunological parameters from nine T. cruzi-seropositive dogs with 10 seronegative healthy mongrel dogs from the city of Mérida, Yucatán, México. Electrocardiograms from 6/9 seropositives animals showed alterations with sinusal arrhythmia in four dogs,
sinusal block in one and right bundle branch block in another dog. One of the seronegatives dogs
showed sinusal block and two presented sinusal arrhythmia. Gross pathology of the heart indicated some
ventricular dilatation (right or biventricular) in seropositive dogs. Leucograms showed no differences in
most cell types, except for lymphocytes, which were significantly higher in seropositive dogs. Further
parasitological and immunologial analysis should provide a complete clinical picture of Chagas disease in
naturally infected dogs, and these data would be of major usefulness for experimental infection studies.
254
Comparative Study of Muscular Histotropism of Five Mexican Trypanosoma cruzi Strains. O.R.
DOBROVINSKAYA*, Center for Biomedical Research, University of Colima, Colima, V.G. MELNIKOV,
F. ESPINOZA-GÓMEZ, O. NEWTON-SÁNCHEZ, F. GUZMÁN-RODRÍGUEZ, Faculty of Medicine,
University of Colima, Colima, F. FIERRO-VELASCO, Faculty of Medicine, Autonomous University of
Guadalajara, Guadalajara, Jalisco, B. ESPINOZA and I. MARTÍNEZ, Institute for Biomedical Research,
National Autonomous University of México, México DF, México.
Chagas´ disease is a significant public health problem in Latin America. Recently, due to intensive
migration and tourism, this illness became distributed worldwide to the areas where it was unknown
previously. The early diagnosis of new cases and the appropriate treatment will decrease the number of
chronic cases. For early diagnosis, the detailed description of characteristic pathomorphology in the acute
phase of disease is needed. It is well known that Mexican strains of T. cruzi possess cardiomyotropism
with predominant affection of myocardium. But cardiological lesions normally are revealed in the
advanced phases of infection when conventional treatment used in the clinic is already ineffective. Then
we addressed the question, if the lesions of skeletal muscles resulted in myositis in the acute phase of
infection might serve for the earlier diagnosis? Although the presence of amastigotigote nests and
resultant tissue damage in skeletal muscle during the acute phase, the question is described in numerous
studies, the information about special preferences in skeletal muscles is limited. In the present work,
parasitism and histopathology of diaphragm, abdominal, lumbar back and femoral muscles caused by five
T. cruzi strains isolated in different regions of México was studied and compared with myocardium. All
five strains were shown to affect predominantly myocardium. Four of five genetically related strains had
demonstrated the same muscle tissue preferences as following: myocardium > abdominal muscle >
lumbar back muscle> femoral muscle > diaphragm. The correlation between severity of parasitism in
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abdominal muscle and in myocardium was found. To predict the severity of lesions in the heart in
chagasic patients, we propose the examination of biopsy from abdominal muscle.
255
Effects of Taenia crassiceps Infection on the Estrus Cycle and Sexual Behavior Pattern in Female Mice.
M. ARTEAGA-SILVA*, Departmento de Biología de la Reproducción, Universidad Autónoma Metropolitana, Iztapalapa, México DF, M. RODRÍGUEZ-DORANTES, Departamento de Inmunología,
Instituto de Investigaciones Biomédicas, UNAM, México DF, and J. MORALES-MONTOR, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
Previously, we demonstrated that Taenia crassiceps cysticerci alter endocrine as well as behavioral aspects
of the male host during chronic infection. For instance, it has been shown that as infection advances,
serum estradiol levels increase to 200 times their normal values, while testosterone serum levels are 90%
decreased. This change in the levels of sex steroids is associated with a complete loss of the typical sexual
behavior in the male mice. However, so far in female mice, there are no studies demonstrating that
Taenia crassiceps infection has endocrine effects. Thus, the aim of this study was to correlate the time of
infection with Taenia crassiceps to the estrous cycle, serum steroids levels and sexual behavior in female
mice. The vaginal estrus cycle was monitored daily, in both control and 4, 8, 12 and 16 wk-infected
female mice. The tests of Female Sexual Behavior (FSB) were performed during this time, one test a
week. Immediately after the last behavioral test, the blood for steroid determinations was collected by
cardiac puncture in female mice. Histological analysis of the uterus and ovaries was performed; all the
cysts found inside the peritoneal cavity were collected after thorough rinsing with PBS and counted. The
estrous cycle showed alterations starting at the sixth week of infection. After that time, there was an
interruption in the cycles at 12 wk and 16 wk. The FSB decreased during the next weeks of infection. At
16 wk of infection, all parasitized female mice ceased to exhibit any sexual responses. Female mice of the
control group continued showing FSB and continued cycling throughout the observation period.
Infected female mice also showed a remarkable infiltration of inflammatory cells in their uterus and
ovaries in the week 12 and 16 post-infection. The values of serum estradiol showed a significant decrease
in these weeks. The changes in estrous cycle and the inhibition of FSB during the infection period could
be the result of a decrease in estradiol levels and the immune response of the host.
256
Sexual Dimorphism of Cytokines and Sex Steroid Receptors During Murine Cysticercosis. M.A. DE
LEÓN-NAVA*, J.A. VARGAS-VILLAVICENCIO, C. LARRALDE and J. MORALES-MONTOR, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
Parasites are able to provoke diverse consequences on their hosts, including alterations in immune and
neuroendocrine systems. In Taenia crassiceps cistecercosis, females sustain larger intensities of infection
than males, suggesting an important role of sex steroids in parasite establishment and reproduction.
Although we know that many aspects of immune system are modified by infection, there is little evidence about the influence of sex in cytokines and steroid receptors expression during infection. Cytokine
secretion is a crucial aspect in immune system modulation. Secretion pattern of these molecules determines the immune response that will confront a particular antigen. The aim of this work was to explore
the sex differences in cytokines and steroid receptors expression in spleen of mice infected with Taenia
crassiceps cisticerci. To answer this question, spleen of mice of both sexes, intact and gonadectomized
(GX), were extracted and gene expression of interleukin (IL)-2, IL-4, IL-6 and interferon (IFN)-γ;
estrogen receptors (ER), α and β; progesterone receptors (PR), A and B; and androgen receptor (AR),
were determined by real time RT-PCR. Results indicate that males mice infected express two-fold less IL2 than infected females; however, when mice were GX, there was no sex difference. IFN-g expression was
no different in intact mice, but GX females express three-fold more than males; IL-4 expression was
higher in intact and GX males than females, but mice infected expressed more IL-4 than controls; IL-6
expression was higher in infected animals than controls in both groups, intact and GX. Sex steroid
receptors also present differences, mainly in estrogen and progesterone receptors: expression of ER-α and
ER-β always increased in infected animals. RP-B expression also is affected by infection. These results
indicate that cytokines and steroids form a common chemical language effective to keep the balance
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between immune and endocrine systems; these interactions represent a fundamental consideration
regarding the maintenance of homeostasis and the development of disease during parasite infection.
257
Progesterone Receptor Expression in the Central Nervous System of Feminized Infected Male Mice. M.
RODRÍGUEZ-DORANTES*, Departamento de Inmunología, Instituto de Investigaciones Biomédicas
UNAM, México DF, M.A. CERBÓN-CERVANTES, Departamento de Biología, Facultad de Química,
UNAM, México DF, and J. MORALES-MONTOR, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
Progesterone participates in the regulation of developmental processes in the brain and controls the
function of distinct behaviors in mammals via its binding to intracellular progesterone receptors (PR).
The PR is expressed as two isoforms: a full-length form (PR-B) and the N-terminally truncated one (PRA). Experimental intraperitoneal Taenia crassiceps cysticercosis in mice exhibits the tendency of parasites
to grow faster in hosts of the female sex and the feminization process that the infection induces in
chronically infected male mice, characterized by their oestrogenisation, deandrogenisation and loss of
sexual and aggressive patterns of behavior. Hence, we suspected that changes in PR expression in the
brain could be involved in the feminization of the infected male mice and in the loss of the sexual and
aggressive behaviours. We have studied the expression of progesterone receptor (PR) isoforms in the
normal and infected male mouse brain. Transcripts of both receptor isoforms (PR-A and B) were detectable in normal and infected mice, but regulated differentially during infection and depending of the area
of the brain studied. Although the precise function of progesterone in the behavioral changes produced
during infection in the male mice is not fully understood, our data implicate a potential role for PR
signaling for the developing of the feminization process. Possibly, the host’s CNS activity is involved in
the network that regulates the oestrogenisation and deandrogenisation observed in chronically infected
male mice, as well as in the behavioural peculiarities observed in this parasitic infection.
258
Prevalence of Perkinsus marinus of the Eastern Oyster Crassostrea virginica, SW Gulf of México:
Environmental, Physiological and Immunological Factors Associated. M. GULLIAN-KLANIAN*, L.
AGUIRRE-MACEDO and R.D. RODRÍGUEZ-CANUL, CINVESTAV, Unidad Mérida, Mérida, Yucatán,
México.
Oysters living in tropical Lagoons are often subjected to harsh living conditions associated with frequent
changes in their aquatic environment affecting host–parasite interactions. The protozoan Perkinsus
marinus is considered the most important pathogen of the eastern oyster Crassostrea virginica, causing
high mortality in natural beds. Forty-five samples involving 945 oysters were tested in the dry, rainy and
north-wind seasons to describe the current state of the P. marinus prevalence in the Terminos Lagoon
related to environmental factors. In addition, the association of the infection with physiological and
immunological parameters was studied. Fluid Thioglycollate Medium technique and Polymerase chain
reaction were applied to determine the infection intensity and prevalence. The prevalence was different
(two-way ANOVA; F (6,2) = 109, p < 0.0001) among seasons with values of 70%, 23% and 7% in the
dry, rainy and north-wind seasons, respectively. Inter-season’s salinity, phosphorus and silica variation
showed a high correlation with prevalence. The oysters’ health comparison to assess seasonal effects
showed the rainy season as a stressful period. Redundancy analysis (RDA) showed that 34% of the
variation in the seasonal infection was explained by protein concentration (21%), lysozyme (12%), and
agglutination (1%). The data suggest the contention that freshwater input associated with high nutrient
concentrations have a strong effect on P. marinus replication and also influence the oysters’ physiology. It
is probable that this dynamic was influencing or controlling the occurrence of an epizootic event in the
Terminos Lagoon.
259
Preliminary Evidence and Pathogenic Effects of Panulirus argus Virus 1 (PaV1) in the Caribbean Spiny
Lobster from the Reef Lagoon, Puerto Morelos, México. J.P. HUCHIN-MIAN* and R. RODRÍGUEZCANUL, Departamento de Recursos del Mar, CINVESTAV-IPN, Unidad Mérida, Yucatán, E. LOZANOÁLVAREZ, P. BRIONES-FOURZÁN, Laboratorio de Crustáceos, UNAM, Unidad Puerto Morelos,
168
ABSTRACTS
Cancún, Quintana Roo, C. PASCUAL-JIMÉNEZ, Facultad de Ciencias, UNAM-Sisal, Puerto de Abrigo
Sisal, Yucatán, and E. ARIAS-BAÑUELOS, Departamento de Recursos del Mar, CINVESTAV-IPN,
Unidad Mérida, Yucatán, México.
In 1999, the first pathogenic virus, PaV1 (Panulirus argus virus 1), in the spiny lobster Panulirus argus
was reported. This virus infects mainly juvenile lobster and its clinical symptoms are: reddish cuticle,
lethargy, milky hemolymph, lack of clotting of the hemolymph with damage of two classes of hemocytes:
hyalinocytes and semigranulocytes. Later in 2004, some P. argus were found in the reef lagoon of Puerto
Morelos, México with the same symptoms caused by PaV1. The main pathogenic effects originated by
the virus infection were: eosinophilic Cowdry-type A inclusions, melanised nodules, tissue necrosis and
fibrosis in the hepatopancreas. The total hemocytes count (CTH) from infected lobsters was significantly
lower than in healthy lobsters (p < 0.05). The bacterial analysis showed that the majority of the strains
isolated from the hemolymph of diseased and non-diseased lobsters are within the family Vibrionaceae
(three spp.), Enterobacteriaceae (three spp.) and aerobic microaerophilic (four spp.). The protein profile
(SDS-PAGE) of hemolymph of infected lobster showed lower molecular weights bands: 3.7 KDa, 3.5
KDa and 2.4 KDa, some others were located up 8 KDa. The Caribbean lobster is considered an important fishing resource in southern México and the characterization of the pathogenic effects of this new
disease is relevant.
260
Coccidiosis Control in Poultry as a Model for the Control of Malaria. E.H. LEE, Vetech Laboratories Inc.,
Guelph, Ontario, Canada.
Coccidiosis is an endemic disease perpetuated by self-infection of chickens that pick up oocysts of
Eimeria spp. from the litter in crowded commercial barns. Like Plasmodium spp, Eimeria spp. are obligate
intracellular parasites and are similarly known to show “infection (concomitant) immunity” (Belkaid et
al., 2002) or “premunition,” where a small number of parasites were found to persist in the infection site
enabling the host to be protected from further infection. Coccidiosis, like malaria, requires a constant use
of medications for its control. This has led to the continuous emergence of drug-resistant coccidia. The
development of live coccidiosis vaccines as an alternative was spurred by the early realization that, in
crowded commercial barns, without efficient coccidiosis control, there would be no poultry industry.
Live vaccines of field isolates have been used for more than 50 years and more successfully for more than
20 years since the concept of uniform exposure was introduced (Lee, 1986). More than 10 billion
chickens and turkeys have been vaccinated to date, showing efficacy and sustainability of coccidiosis
control with live vaccines. The combination of vaccination and medication for the control of coccidiosis
(Lee, 2001), in particular, is most applicable to the control of malaria. With drug-sensitive strains of
Plasmodium spp. as a live vaccine, the risk of runaway vaccinations can be safeguarded with antimalarials.
In any event, use of live vaccines has been in practice for the past few years in the Intermittent Preventative Treatment in infants (IPTi) program with the goal of reducing the incidences of malaria and severe
anemia in Africa (Schellenberg et al., 2001). Last, but not least, affordability, the prime consideration in
the poultry industry, also is critical to the success here. of all the potential vaccine seeds, field isolates that
are readily available will bear the least cost.
261
Immunomodulatory Role of Pyrimethamine in Malaria-infected Mice. M. LEGORRETA-HERRERA* and
A. RAMOS-AVILA, FES Zaragoza, Posgrado en Ciencias Biológicas, UNAM, México DF, México.
Pyrimethamine (PYR) remains among the most commonly used antimalarial drugs, even in endemic
regions where the parasite has developed resistance. This drug is very versatile since it also is used
successfully for the treatment of some autoimmune disorders as lymphoproliferative syndrome. Although
its mechanism of action is only partially understood, their therapeutic effectiveness has been attributed to
its ability to increase apoptosis of T lymphocytes, which in turn contributes to the downregulation of
destructive inflammatory response. In view of the potential for immunomodulation during malaria
chemotherapy, we investigated the effect of PYR treatment on lymphocyte apoptosis and cytokine
mRNA expression during infection with Plasmodium yoelii 17XL. Groups of BALB/c mice were infected
iv with the parasite, on day 7 post-infection were treated with a single dose of pyrimethamine, 24 hrs
later mice were sacrificed, and the spleen cells were used to evaluate apoptosis and mRNA expression of
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ABSTRACTS
Fas, TNF-α and iNOS by RT-PCR. The results indicate that pyrimethamine treatment increases apoptosis and mRNA expression of iNOS, but does not modify the expression of Fas or TNF-α. These
findings suggest that apoptosis induced by PYR is independent of Fas or TNF-α mRNA expression;
however, iNOS expression is probably involved. This work provides information of how pyrimethamine
treatment modulates the immune response during a malaria infection. (Work supported by PAPIIT
IN214007 and PAPIME PE204105 Grants.)
262
Toxoplasma gondii-specific Classes and Subclasses in Mother/Newborn Pairs. I. CAÑEDO-SOLARES*,
Lab. Inmunología Experimental, Instituto Nacional de Pediatría, SSA, México DF, M. GALVÁNRAMÍREZ, Universidad de Guadalajara, Jal, H. LUNA-PASTÉN, Lab. Inmunología Experimental,
Instituto Nacional de Pediatría, SSA, México DF, L. RODRÍGUEZ-PÉREZ, Universidad de Guadalajara,
Jal, L.B. ORTÍZ-ALEGRÍA, C.P. RICO-TORRES, Lab. Inmunología Experimental, Instituto Nacional de
Pediatría, SSA, México DF, M. VELA-AMIEVA, M. PÉREZ-ANDRADE, Genética de la Nutrición, Instituto
Nacional de Pediatría, SSA, México DF, and D. CORREA, Lab. Inmunología Experimental, Instituto
Nacional de Pediatría, SSA, México DF, México.
Most cases of congenital toxoplasmosis are asymptomatic at birth. Immune control is mediated mainly
by the cellular arm, but antibodies (abs) of the IgG1 and IgG3 classes bind to phagocytes and natural
killer cells (NKs) through Fc receptors, which are effective in destroying the parasite. These abs, then, are
expected in mothers or newborns protected from vertical transmission or from parasite-induced damage.
Conversely, IgG2 and IgG4 are induced or enhanced by Th2 cytokines, and their presence could be
associated with a bad clinical outcome. Forty-seven mother/newborn pairs of sera were selected from
banks previously studied, which included cases from high-risk gynecology hospitals or screening programs. All newborns were of minutes to 40 days of age. They were classified according to infection
probability as non-congenitally infected or “infected,” by follow up and/or a serology panel of one, three
and two different techniques for IgA, IgM and IgG antibodies, respectively, and total abs, assayed by
capture and indirect ELISAs, IFAT, Immunoblot and dye test. All IgG subclasses were tested by indirect
ELISA against a crude antigen. The results of 41 negative control pairs were used to determine the cut
offs for each subclass. IgG1 was the most frequently recognized antibody in mothers and children;
among “infected,” its presence in the mothers was related to a bad clinical outcome in the offspring. All
mothers were negative for IgG3 antibodies, while there were three positive newborns, all “infected” and
with clinical symptoms. IgG2 was a marker of vertical transmission if present in the newborns sera, while
the presence of IgG4 in the mothers or children was associated to newborn clinical problems. Passive
transfer of IgG1 (mostly), IgG2 and IgG4 was supported by correlation of values between mothers and
offspring in some pairs of the non-infected group. The role of different subclasses in congenital infection
by Toxoplasma gondii could be different to that expected from their cytokine control and effector mechanisms. (Partially supported by Grant U-43079-M from CONACYT, México.)
263
Toxoplasma gondii Infection in Mothers Induces Changes in Lymphoid Organs of Neonatal Mice. M.A.
CABAÑAS-CORTES*, Laboratorio de Inmunología Clínica, Dpto. de Inmunología, Escuela Nacional de
Ciencias Biológicas, IPN, México DF, E.A. GARCÍA-LATORRE, Laboratorio de Inmunoquímica, Dpto.
de Inmunología, Escuela Nacional de Ciencias Biológicas, IPN, México DF, E. REYES-MALDONADO,
Laboratorio de Citología, Dpto. de Morfología, Escuela Nacional de Ciencias Biológicas, IPN, México
DF, and L.A. JIMÉNEZ-ZAMUDIO, Laboratorio de Inmunología Clínica, Dpto. de Inmunología, Escuela
Nacional de Ciencias Biológicas, IPN, México DF, México.
Primary Toxoplasma gondii infection during human pregnancy can lead to spontaneous abortion, neonatal
death, and severe congenital defects, such as hydrocephalus, chorioretinitis, blindness and mental retardation. Severity has been related to the time of the mother’s infection. Although several aspects of toxoplasmosis have been studied, alterations in the lymphopoietic system and its contribution are still poorly
understood. We studied the changes in the lymphoid organs in Balb/c mice neonates from mothers
infected with T. gondii at day 19 of gestation. Percentages of plasma cells were significantly increased,
while percentages of lymphocytes and monocytes were significantly decreased in bone marrow from the
same neonates. Weight of the thymus and the number of thymic cells were dramatically decreased and
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ABSTRACTS
basal apoptotic cells increased. Weight of the spleen was significantly decreased. CD4+CD25+ and
CD8+CD25+ subpopulations both in the thymus and in the spleen increased. Results indicate that
infection of the mother at day 19 of gestation primarily provokes in the neonates changes in the lymphoid organs. The decrease of lymphocytes in bone marrow could be the reason for the diminution on
the weight of the thymus, though other factors also could affect the arrival of lymphocytes to this organ.
The increase in plasma cells and CD4+CD25+ and CD8+CD25+ lymphocytes suggests an activation
of the immune response possibly due to the infection with T. gondii. Changes in the lymphoid organs can
contribute to the severity of the disease in early periods of the development.
264
Evaluation of the Immunogenicity of LYT1 Recombinant of Trypanosoma cruzi. C.E. ANGULO-ROJO*,
L. CEDILLO-BARRON, J. CABRERA-CORDERO and R.G. MANNING-CELA, Biomedicine Molecular
Department, CINVESTAV, México DF, México.
Trypanosoma cruzi is the causative agent of Chagas’ disease or American trypanosomiasis, which affects
more than 16 to 18 million of individuals, killing around 200,000 people annually, with another 100
million at risk of acquiring the disease. So far no effective treatment for chronic stage or effective vaccine
is available. The parasite undergoes a complex biphasic life cycle, comprised four distinct developmental
stages alternating between the Reduviid beetle vector and the mammalian host. During its intracellular
stage in mammal cells, the parasite invades diverse professional and non-professional host cells by a
complex infection process that involve diverse parasite and host cell molecules. Though many proteins
are undoubtedly important for T. cruzi infection and successful completion of the life cycle, surprisingly
few have been identified experimentally. We reported the genetic characterization of LYT1, which are
shown to have lytic activity in acid conditions and participate in the exit of the parasite form the parasitophorous vacuole. Also, we demonstrated its critical role during the infection process. As recombinant
LYT1 protein was recognized by serums of Chagasic patients by Western blot, we continue with the
immunologic characterization of LYT1. Then, in the present work we obtained and evaluated the
immunogenicity of the complete sequence of LYT1 and three different LYT1 domains by ELISA. Using
the different recombinant proteins, we will present the analyses of their recognition by serums of chagasic patients in the indeterminate phase, cardiopathy chagasic patients, cardiopathy not-chagasic patients,
patients with Leishmaniasis and health people and their capacity to induce protection in a murine model.
265
The Multiepitope Anticysticercosis Vaccine from Laboratory to the Field: Novel Delivery Systems and
Alternative Routes for Vaccine Administration. E.L. SCIUTTO*, M. HERNÁNDEZ, Instituto de Investigaciones Biomedicas, UNAM, Immunology Department, Ciudad Universitaria, México DF, J. MORALES,
Facultad de Medicina Veterinaria y Zootecnia, UNAM, Ciudad Universitaria, México DF, G. ROSAS, A.
TOLEDO, Immunology Department, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México DF, M. HUERTA, Benemerita Universidad Autónoma de Puebla, Facultad de Medicina,
Puebla, Pue. México, A. DIAZ, Centro de Investigacion Biomedica de Oriente, IMSS, Puebla, Pue.
México, J. CERVANTES, Immunology Department, Instituto de Investigaciones Biomedicas, UNAM,
Ciudad Universitaria, México DF, J.J. MARTÍNEZ, A. ALUJA, Facultad de Medicina Veterinaria y
Zootecnia, UNAM, Ciudad Universitaria, México DF, G. GEVORKIAN, G. ACERO, Immunology
Department, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México DF, L.
HERRERA-ESTRELLA, J.L. CABRERA-PONCE, CINVESTAV, Unidad de Biotecnologia e Ingenieria
Genetica, Irapuato, Gto. México, F. LÓPEZ-CASILLAS, Instituto de Fisiología Celular, Biología Celular,
Ciudad Universitaria, México DF, A. BLANCAS, Immunology Department, Instituto de Investigaciones
Biomedicas, UNAM, Ciudad Universitaria, México DF, K. MANOUTCHARIAN, Instituto de Investigaciones Biomedicas, Biologia Molecular, Ciudad Universitaria, México DF, G. FRAGOSO and C.
LARRALDE, Immunology Department, Instituto de Investigaciones Biomedicas, UNAM, Ciudad
Universitaria, México DF, México.
Taenia solium cysticercosis is a major parasitic disease that seriously and frequently affects human health
and economy in underdeveloped countries. Since pigs are indispensable intermediate hosts, transmission
can be interrupted by reducing pig cysticercosis through their effective vaccination. Three protective
peptides, namely KETc12 (8 aa), KETc1 (12 aa) and GK1 (18 aa), identified in a cDNA library from
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ABSTRACTS
Taenia crassiceps and present in T. solium composed the S3Pvac anti-cysticercosis vaccine. S3Pvac synthetically produced induced high levels of protection against naturally acquired porcine cysticercosis. A new,
low-cost version of S3Pvac delivered in filamentous phages has been developed and its massive production optimized to minimal costs. This new version has been tested successfully by experimental challenge,
as well as in the field, in naturally exposed rural pigs, and will be soon available on the market. Simultaneously, transgenic papaya clones expressing the vaccine’s peptides were developed. A group of transgenic clones that induced a high level of protection against murine T. crassiceps cysticercosis—our vaccine
candidates’ first hurdle to overcome systemically and orally administered—were identified. This oral
vaccine is now under evaluation in pigs naturally exposed to T. solium. Overall, these advances offer new
insights in cysticercosis prevention and in the development of new antigen delivery systems useful for the
design of more effective and affordable oral subunit vaccines to be feasible applicable in the endemic
countries stringent economies.
266
Neurocysticercosis: Immunological Predictive Markers for Treatment Prognosis. D. SAN JUAN, Dpto.
de Neurologia, Instituto Nacional de Neurologia y Neurocirugía, México DF, B.I. SAENZ, Dpto. de
Inmunologia, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México DF, A.
CHAVARRIA, Dpto. Medicina Experimental, Facultad de Medicina, UNAM, México DF, C. MÁRQUEZ,
Dpto. de Neurologia, Instituto Nacional de Neurologia y Neurocirugía, México DF, G. FRAGOSO, E.L.
SCIUTTO, Dpto. de Inmunologia, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México DF, and A. FLEURY*, Dpto. de Investigacion Clinica, Instituto Nacional de Neurologia y
Neurocirugía, México DF, México.
Neurocysticercosis (NC) is a clinical, immunological and radiological heterogeneous disease. Response
to cysticidal treatment also is heterogeneous: one single cycle of albendazole can lead to cysticercal
calcification in some patients, while more than five cycles can be necessary in others. Cysticerci localization in the central nervous system (CNS) is one of the main factors that contribute to these differences.
Parasite immunity that modulate the inflammatory response also could be involved. The purpose of this
study was to identify immunological features in relation to the success of the parasite destruction after
cysticidal treatment. Thirteen vesicular NC patients (five women and eight men, mean age: 36 ± 13.8)
were included before treatment between 1998 and 2002. The level of specific sera antibodies were
measured (IgG1, IgG2, IgG3, IgG4). The following cytokines (IL1β, IL4, IL5, IL6, IL10, IL12, IL13,
TNFα, INFγ) were also measured in the supernatants of peripheral cells specifically stimulated with
cysticercal antigens. Each treatment cycle was albendazole 30 mg/kg/day for eight days. Patients were
followed until the disappearance or calcification of the cysticerci. Responders were defined as those who
required only one cycle for the parasite destruction or disappearance. As expected, a significant lower
response to treatment was observed when parasites were located in the ventricles or in the subaracnoideal
space of the basal cisterns (P < 0.05). Interestingly, non-responders exhibited increased levels of IL1 (P
= 0.035), TNFα (P = 0.07), and IL6 (P = 0.07). After logistical regression, increased levels of IL12 (P
= 0.01) and parasite localization (P = 0.003) were the two prognostics factors related to non-response
to treatment. In summary, herein we report for the first time some prognostic immunological features
that could be of use for the better management of NC patients.
267
Exploring Different Systemic and Oral Antigen Delivery Systems to Improve the Anti-cysticercosis
Vaccine. J. CERVANTES and M. HERNÁNDEZ, Departamento de Inmunologia, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México DF, K. MANOUTCHARIAN, Departamento
de Tecnologia, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México DF, G.
GEVORKIAN, G. ACERO, Departamento de Inmunologia, Instituto de Investigaciones Biomedicas,
UNAM, Ciudad Universitaria, México DF, J.L. CABRERA-PONCE, L. HERRERA-ESTRELLA, Departamento de Ingeniería Genética de Plantas, CINVESTAV-IPN, Irapuato, Gto. México, N. AINCIART, F.A.
GOLDBAUM, Fundación Instituto Leloir, Universidad de Buenos Aires, Buenos Aires, Argentina, G.
FRAGOSO and E.L. SCIUTTO*, Departamento de Inmunologia, Instituto de Investigaciones Biomedicas, UNAM, Ciudad Universitaria, México DF, México.
172
ABSTRACTS
A highly effective vaccine against murine and porcine cysticercosis based on three synthetic peptides
(S3Pvac) has been developed. Its well-characterized components and the murine model offer the possibility of exploring different delivery systems and oral formulations of potential usefulness for subunit
vaccines improvement. In this study, one of the S3Pvac components, KETc1, was recombinantly expressed in transgenic papaya callus, in the decameric lumazine synthase enzyme from Brucella spp. and
displayed to the M13 filamentous bacteriophage pill coat protein. The protective and immunogenic
properties of the different constructions were tested on mice by oral and systemic immunization. The
immunogenecity and protective capacity was enhanced effectively depending on the vaccine formulation
and administration route. Results highlight the effectiveness of the transgenic papaya oral delivery
system, pointing its usefulness to effectively improve the anti-cysticercosis vaccine and bypassing the
logistic problems related to its massive and extensive application. Its usefulness for the improvement of
other subunit vaccines has to be considered.
268
The Use of Taenia solium Synthetic Peptides Derived from a 26 kDa Antigenic Region to Assess
Serodiagnosis of Porcine Cysticercosis. J.A. PÉREZ-VEGA *, R.D. RODRÍGUEZ-CANUL, Laboratorio de
Inmunologia y Biologia Molecular, F. CEN-AGUILAR, Departamento de Investigación, Mérida, México,
and P.S. CRAIG, Cestode Zoonoses Research Group. University of Salford, Salford, U.K.
Cysticercosis is a disease of the central nervous system caused by the larvae stage of the parasite Taenia
solium, which in its life cycle involves humans as the definitive and accidental host and pigs as intermediary hosts. Serodiagnosis of cysticercosis is based on detection of specific Taenia solium antibodies in pigs.
In this study, 10 T. solium synthetic peptides (TS1-10) were developed from a 26-kDa antigenic region of
a saline extract of T. solium metacestodes in immunoblot. The TS1-10 were evaluated individually in a
simple ELISA based format at 630 nm. The positive control group included 30 infected pig sera previously confirmed by immunoblot, tongue palpation and necropsy, compared to 30 healthy pig sera.
Likewise, a panel of sera with other parasitic infections was used as the heterologous group. The optimal
working concentration of each peptide was of 10 ng/well; sera dilution was of 1:40 and whole pig IgG
conjugate was of 1:45000. The cut-off value ranged from 0.3 to 0.55. The sensitivity of TS1-10 ranged
from 96% to 100% and a 100% of specificity was observed in each case. In a controlled infection, eight
pigs were challenged orally with 50,000 eggs of T. solium, and an specific T. solium antibody response was
detected at week 8. The use of TS 1-10 can be useful to assess diagnosis of porcine cysticercosis.
269
Expression of Group V Secretory PLA2 in Macrophages During Amoebic Liver Abscess Formation. B.E.
SÁNCHEZ-RAMIREZ*, M. MOGUEL-TORRES, Lab. Biotecnologia, Fac. Ciencias Quimicas, Universidad
Autónoma de Chihuahua, E. RAMOS-MARTÍNEZ, Depto. Anatomia Patologica, Fac. Medicina, Universidad Autónoma de Chihuahua, and P. TALAMÁS-ROHANA, Depto. Patologia Experimental,
CINVESTAV-IPN, México.
Prostaglandin E2 (PGE2) produced by macrophages (MOs) expressing cyclooxygenase-2 (COX-2) may
play an important role in promoting inflammation during hepatic infection with E. histolytica. Supply of
arachidonic acid for COX-2-dependent PGE2 production involves the activity of group V secretory PLA2
(sPLA2V). A specific coupling between certain PLA2 and COX isoforms has been reported. Catalytically
active sPLA2V is needed for the cells to produce PGE2, which in MOs involved exclusively COX-2. To
demonstrate sPLA2V expression in MOs, sPLA2V and COX-2 were immunolocalized in liver from
intrahepatically infected hamsters at 2, 4 and 7 d post-infection. Results demonstrated that at 2 d postinfection, sPLA2V was localized in the cytosol of MOs from areas near and far from the abscess. Furthermore, at 4 d the number of sPLA2V-positive MOs increased significantly in comparison with the amount
present at 2 d. At day 7, although necrosis area was larger than that seen at 4 d, sPLA2V-positive MOs
diminished. In addition, MOs coexpressing sPLA2V and COX-2 were localized in the necrosis area
surrounding clusters of trophozoites, suggesting that co-expression probably depends of continuous
interaction between MOs and the parasite and/or secretion products. MOs expressing only sPLA2V were
detected in necrosis area in the absence of trophozoites, linking the expression of this enzyme with cell
debris elimination function. These results demonstrate that amoebic trophozoites can induce the expres173
ABSTRACTS
sion of COX-2 and sPLA2V in MOs, and that these enzymes can contribute to initiate and sustain the
inflammatory process during liver infection.
270
Induction of Amoebic Liver Abscess in a IL-6 KO C57bl/6 Mice. M. ESQUIVEL VELÁZQUEZ*, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, E. ESTRADAVILLASEÑOR, Departamento de Patología, Instituto Nacional de Rehabilitación, Secretaría de Salud,
México, J. MORALES, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM,
México DF, E. RAMOS-MARTÍNEZ, M. NEQUIZ-AVENDAÑO, Facultad de Medicina, Departamento
de Patología Experimental, UNAM, México DF, and P. OSTOA-SALOMA, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
Amoebiasis is a disease that only affects naturally the human being and is caused by the parasite Entamoeba histolytica. In some cases, the normal intestinal infection disseminates to other organs as the liver in
which trophozoites establish, causing an abscess. This work reports the induction of hepatic abscess in an
IL-6 KO murine model of disease and assesses the possibility of using this model for the study of
immunological or another factors involved in the natural murine resistance to infection with E. histolytica. For the induction of the abscess, axenically grown amoebas were injected directly into the liver. The
formation of the abscess, as well as the inflammatory response, was assessed at several time-points. The
inflammatory response at the beginning of the infection (day 10) was composed predominantly by
eosinophils. Additionally, the cytokine response also was assessed. RT-PCR was performed to evaluate
the expression of IL-4, IFN-γ; and IL-10. No meaningful differences were found in the levels of expression of these cytokines between the control group and the KO group. The absence of IL-6 is, then, a
factor that confers susceptibility to the development of amoebic liver abscess in mice.
271
Malaria Parasites (Plasmodium) in Invasive Brown Anoles (Anolis sagrei) in Florida. S.L. PERKINS*,
Division of Invertebrate Zoology, American Museum of Natural History, New York NY, A.
ROTHSCHILD, Department of Biology, Brown University, Providence RI, and E. WALTARI, Division of
Invertebrate Zoology, American Museum of Natural History, New York NY, USA.
The malaria parasite, Plasmodium floridense, was described originally from Anolis carolinensis and Sceloporus
undulatus in Florida in 1944, and has since been reported from several islands in the Caribbean. The
invasive Brown Anole, Anolis sagrei, now has become widespread throughout Florida. Surveys showed
infections of P. floridense in A. sagrei, but parasite-positive sites were concentrated primarily in the
central–western and southwestern regions of the state. Tests of environmental factors revealed that
positive sites were significantly more likely to be close to fresh water, presumably because of the presence
of mosquito vectors. The distribution of parasites coincided with differences in the Cuban source
populations of A. sagrei; however, genotyping of hosts from several sites showed that this was not a
significant predictor of infection in each lizard. Broader phylogeographic and coevolutionary analyses
that combine data from Cuba, the Dominican Republic, and other Caribbean islands uncover a complex
history of this parasite.
272
Phenotypic Trade-offs Between Number and Size of Eggs: Are Parasites Different from Free-living
Organisms? V. HERRERAS, Marine Zoology Unit, Cavanilles Institute of Biodiversity and Evolutionary
Biology, University of Valencia, Valencia, Spain, F.E. MONTERO, Department of Animal Biology, Plant
Biology and Ecology, Autonomous University of Barcelona, Bellaterra, Spain, D.J. MARCOGLIESE,
Fluvial Ecosystem Research Section, Aquatic Ecosystem Protection Research Division, Water Science
and Technology Directorate, Science and Technology Branch, Environment Canada, St. Lawrence
Centre, Montreal, Quebec, Canada, J.A. RAGA and J.A. BALBUENA*, Marine Zoology Unit, Cavanilles
Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain.
Because egg number and egg volume compete for the limited energy budget and/or for the limited space
within a mother, a trade-off between both traits is expected. For a number of reasons, however, this
pattern is often not observed in nature. In parasites, it has been argued that because resources provided
by the host are in excess of the parasite needs, mothers can override any conflict in allocation between
174
ABSTRACTS
quantity and quality of eggs. We tested the existence of phenotypic trade-offs between number and size
of eggs in three populations of three anisakid nematode species: Anisakis simplex, Pseudoterranova decipiens
and Contracaecum osculatum. Body and uterine volumes (used as controls of female size) and egg number, mean egg volume and clutch volume (as descriptors of reproductive output) were measured in 50
females of each species. Evidence of a phenotypic trade-off was detected only in A. simplex, the first time
it has been found in a parasite population. A negative relationship between egg size and number arose
when uterine volume was fixed, whereas it was marginally significant when female volume was corrected
for. Thus, the trade-off is probably constructional rather than physiological, illustrating that even if host
resources are unlimited, the trade-off can still occur if physical space for the clutch is limited. Constraints
imposed by uterine volume seemed to operate also in C. osculatum, a species with relatively few and large
eggs, because uterine volume was the main predictor of both egg numbers and clutch volume. However,
the trade-off was not observed in this species, nor in P. decipiens, because interindividual variation in egg
volume was very low, which might indicate optimization of egg size. All this evidence suggests that
patterns relating number and size of eggs in parasites may not differ much from those observed in freeliving populations and thus their interpretation should rest on the same premises in both types of
organisms.
273
Disentangling Host Colonization and Hybridization Patterns in Human and Pig Ascaris: Is It Possible?
C.D. CRISCIONE*, Department of Genetics, Southwest Foundation for Biomedical Research, San
Antonio TX, J.D. ANDERSON, Perry R. Bass Marine Fisheries Research Station, Coastal Fisheries
Division, Texas Parks and Wildlife Department, Palacios TX, D. SUDIMACK, Department of Genetics,
Southwest Foundation for Biomedical Research, San Antonio TX, USA, W. PENG, Jiangxi Medical
Science Research Institute, Nanchang University, Nanchang, Jiangxi, China, M.E. ROMERO-ABAL,
Center for Studies of Sensory Impairments, Aging, and Metabolism, Guatemala City, Guatemala, J.
SUBEDI, Department of Sociology and Gerontology, Miami University, Oxford OH, D.R. RAI, R.P.
UPADHAYAY, Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio
TX, USA, B. JHA, Tribhuvan University Institute of Medicine, Majarajgung, Kathmandu, S. WILLIAMSBLANGERO and T.J. ANDERSON, Department of Genetics, Southwest Foundation for Biomedical
Research, San Antonio TX, USA.
Knowledge of cross transmission between parasites of humans and reservoir hosts is critical for understanding the evolution of the parasite and for implementing control programs. There is now consensus
that populations of pig and human Ascaris show significant genetic subdivision. It is unclear, however,
whether this has resulted from a single or multiple host shifts. Furthermore, the existence of shared
mitochondrial or nuclear polymorphisms, and observations of human infection with pig-derived parasites
in Denmark and the USA raise the possibility of frequent hybridization or host colonization events
between host associated populations. To disentangle patterns of host colonization and hybridization, we
used 23 microsatellite loci to conduct Bayesian clustering analyses of individual worms collected from
pigs (China and Guatemala) and humans (China, Guatemala and Nepal). We observed strong differentiation between populations that was primarily driven by geography, with secondary differentiation resulting from host affiliation within locations. This pattern is consistent with multiple host colonization
events. We note, however, that there is low support for the short, internal branches of the dendrograms.
In part, the relationships among clusters may result from current hybridization among sympatric human
and pig roundworms. We used three Bayesian methods to look for putative hybrids within sympatric
China and Guatemalan populations. All three methods suggest that between 4 to 10% of worms are
hybrids. Simulation tests, however, suggest that caution is required when interpreting these results. Thus,
whether the evolutionary history of Ascaris involves multiple hybridization or host-colonization events is
still an open question. However, the level of differentiation observed in our data set of multiple autosomal markers suggests that either one or both of these processes is preventing complete reproductive
isolation between the host associated populations of Ascaris .
175
ABSTRACTS
274
Global Warming and Disease: Effects on Trematode Cercariae. B.L. FREDENSBORG*, R. SANDOVAL,
K.D. LAFFERTY and A.M. KURIS, Department of Ecology, Evolution and Marine Biology, The University
of California, Santa Barbara CA, USA.
Climate is one factor that can greatly influence the production and transmission of parasite infective
stages. As a general rule, the production of parasite infective stages is positively related to temperature.
This raises concerns that global warming may have widespread effects on the transmission of infectious
diseases and the risk of epizootics within animal communities and ecosystems. This study investigated
the potential consequences of global warming on the transmission of trematode cercariae from the
California horn snail, Cerithidea californica, to fishes and benthic invertebrates in a California saltmarsh
ecosystem. In particular, we investigated temperature-mediated changes in cercarial emergence, survival
and transmission in five trematode species. Our results showed that increasing temperature generally had
a pronounced positive effect on cercarial emergence and a negative effect on cercarial survival. Overall,
more cercariae were transmitted at higher temperatures. Some trematodes, however, showed a much
more rapid increase in transmission with increasing temperature than others, indicating a species-specific
effect of temperature on cercarial transmission to second intermediate hosts. Hence, the predicted
outcomes of global warming on cercarial transmission are two-fold. First, temperature-enhanced cercarial
transmission to second intermediate hosts could affect host fitness, and potentially the structure of
saltmarsh animal communities. Second, species-specific temperature-mediated changes in transmission
could alter trematode communities by favoring species best able to optimize transmission to second
intermediate hosts at higher temperatures.
275
Disinfectant Activity of Three Commercial Formulations and Micronized Calcium Hydroxide Against
blastocystis Hominis. G. IBÁÑEZ-CERVANTES*, R.M. SÁNCHEZ-MANZANO, A. MÁRQUEZNAVARRO and B. NOGUEDA-TORRES, Departamento de Parasitología, Escuela Nacional de Ciencias
Biológicas del IPN, México DF, México.
Blastocystis hominis is a unicellular organism that in certain conditions can cause gut disease. Humans can
become infected by consumption of water and/or polluted foods with infecting forms of B. hominis. For
the above-mentioned, disinfection of water and/or foods is of interest, since there are communities where
the disposition of drinkable water is limited. In present work, the disinfectant effect of three commercial
products with antimicrobial proprieties and the micronized calcium hydroxide (Ca(OH) 2) in polluted
water with parasitic forms of B. hominis obtained from human feces was evaluated. The commercial
disinfectants were prepared and allowed to act according to the manufacturer’s instructions. Suspensions
of Ca(OH) 2 ranged 0.5 to 0.0019% were prepared and allowed to act during two minutes. Once
treated, the viability of B. hominis was determined, both by the neutral red staining method (Alexandre
method) and cultured in two-phase Boeck-Drbohlav medium. The determination of viability by the
neutral red method correlates at 100% with the culture in Boeck-Drbohlav. The commercial disinfectants
evaluated eliminate 92% of B. hominis parasitic forms present in fecal samples and those cultivated in
Boeck-Drbohlav medium. The calcium hydroxide eliminates 100% of B. hominis viable forms at concentrations from 0.0039%, so Ca(OH) 2 could be an alternative as a disinfectant, at least for the parasitic
forms of B. hominis communities where the disposition of drinkable water is limited.
276
Examination of Prezygotic Mating Barriers Between Schistosoma mansoni and Schistosoma rodhaini.
E.S. HATTON*, M.L. STEINAUER and E.S. LOKER, Department of Biology, The University of New
Mexico, Albuquerque NM, USA.
Schistosoma mansoni, a medically important digenetic trematode that causes human schistosomiasis, and
its sister species, Schistosoma rodhaini, are sympatric over parts of their geographic ranges in Africa. The
two species infect the same species of intermediate host and are capable of infecting the same species of
definitive host. Successful hybrids have been created in the laboratory and a natural hybrid has been
reported from the field, which calls into question the reproductive barriers that allow these two species to
exist in sympatry. We used experimental infections and molecular techniques to elucidate interspecific
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ABSTRACTS
interactions and mating behavior of parasites inside the host where direct observation is impossible. Mice
were co-infected with varying ratios of S. mansoni and S. rodhaini, which were allowed to mature and
mate for nine weeks. The worms were recovered by perfusion and genotyped at seven microsatellite loci
using established markers to discover the specific identity of pairs found in copula and of unpaired
worms. The results were compared against the null hypothesis of random mating (no reproductive
barriers) and the hypothesis that pairing will be homospecific unless homopsecific mates are unavailable
(strong reproductive barriers). Results show that mate choice plays a role in the reproductive isolation of
these species; however, it is imperfect and hybridization is likely to occur even when homospecific mates
are present.
277
Distribution and Abundance of Parasites of Kelletia kelletii, a Marine Whelk with a Recent Range
Expansion. J. LORDA*, J.V. HOPPER, C. WHITE, Department of Ecology, Evolution and Marine Biology,
University of California, Santa Barbara CA, S. KOCH, Department of Biological Science, California
State University, Fullerton CA, and A.M. KURIS, Department of Ecology, Evolution and Marine Biology,
University of California, Santa Barbara CA, USA.
High-latitude species-range expansions, often accredited to climate change, appear to be increasing.
These range extensions may influence ecosystem dynamics, including relationships between parasites and
their hosts. There is a lack of information on host–parasite relationships in expanded ranges, especially
for marine ecosystems. The subtidal gastropod, Kelletia kelletii, is historically native to southern California and Baja California. Recently, this snail has expanded its range northward to multiple coastal areas
between Point Conception and Monterey Bay. We quantified the prevalence and intensity of endoparasitic helminthes and nematodes as well as ectoparasitic shell borers throughout the historical and expanded range. We recovered larval nematodes (gnathostomatids) and larval cestodes (tetraphyllideans,
trypanorhynchs and diphyllids). Prevalence of all parasite taxa was lower in Kelletia’s expanded range
compared to its native range. Prevalence also varied within regions among its historical range. Our
results, however, suggest that marine organisms undergoing range expansion may escape parasitism in
ways parallel to the decrease in parasitism often exhibited by invasive species.
278
Integrating Parasite Community Analysis with Fisheries Oceanography: A More Comprehensive Look at
the Ocean Ecology of Juvenile Pacific Salmonids. K.C. JACOBSON*, Northwest Fisheries Science
Center, NOAA Fisheries, Hatfield Marine Science Center, Newport OR, R.E. BALDWIN, Cooperative
Institute for Marine Resources Studies, Oregon State University, Hatfield Marine Science Center,
Newport OR, D.C. REESE, Northwest Fisheries Science Center, NOAA Fisheries, Hatfield Marine
Science Center, Newport OR, and D.J. TEEL, Northwest Fisheries Science Center, NOAA Fisheries,
Seattle WA, USA.
Ocean conditions play an important role in the survival of Pacific salmonids. This, understanding the
ocean ecology of juvenile salmon is critical for better management of endangered salmonids. We analyzed
the macroparasite communities of juvenile salmon and associated fish nekton to study the effects of
spatial and temporal variability in the California Current on pelagic food web structure and fish habitat
use. We examined the parasite communities of 12 pelagic fish species collected during June and August,
2000 and 2002 between Newport, Oregon and Crescent City, California, USA. Multivariate analysis of
parasite communities separated the fish species into three groups: salmon, forage fish, and predator fish.
In both years, salmon had a greater parasite species richness (12 in 2000 and 17 in 2002) than either the
forage fish (1–4) or the predator fish (1–5). The macroparasite community analysis indicated differences
in diet between Chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) that were not
detected by stomach contents, and provided trophic information on salmon with empty stomachs. In
addition, the multivariate analysis of parasite communities of juvenile salmon reflected the genetic origin
of the salmon, as determined by microsatellite analysis of the hosts. The parasite communities showed no
indication that Cape Blanco, and the physical oceanographic features caused by the cape, separated fish
populations or altered the pelagic food web. We also found no difference in the parasite communities of
fish caught within and outside of areas identified as fish biological hotspots (areas of high ocean productivity). In contrast to the lack of association with spatial variability, there was a temporal variability in the
177
ABSTRACTS
parasite communities among the four sampling periods. These results show how parasite community
data can be incorporated into fisheries oceanography to provide a more comprehensive understanding of
biological responses to ocean productivity and climate variability.
279
A Single-sexed Gordiid (Nematomorpha: Gordiida) Species from Kenya: Its Implications for the
General Biology of the Phylum and for the Need for a Global Gordiid Survey. B. HANELT, Department
of Biology, The University of New Mexico, Albuquerque NM, USA.
Though incomplete, our general textbook knowledge of major taxa has been accepted to be adequate
enough to allow for the painting of an image depicting the real nature of these taxa. Considering the
movement of careers and funding over the last decades, the impression is that additions to this general
knowledge can be made only by way of molecular or biochemical studies. This trend has lead to the near
wholesale abandonment of alpha taxonomy, organismal biology, and other foundation-level areas of
study. The recent discovery of a single-sexed species of parasite within a phylum, always having been
considered dioecious, has highlighted the fact that our most basic understanding of some groups of
organisms is woefully inadequate. In this specific case, snails collected around the Lake Victoria basin in
Kenya were found to contain gordiid cysts morphologically and genetically similar to Paragordius sp.
Cysts were fed to crickets, which released female worms 90 days post-exposure. Within 8–10 hours,
isolated single worms produced viable larvae. Males were never seen, including within the host’s body
after releasing the female(s). The exact method of egg production (mitosis or meiosis) has yet to be
determined. Several species of Paragordius have been noted from Africa. Most of these species descriptions are based only on the female form, since no corresponding males were found, allowing for the
tantalizing speculation that numerous gordiid species have evolved to function as a single sex. These
intriguing observations will force the rethinking of gordiid biology and hopefully will inspire young
scientists to once again consider careers in organismal parasitology. Furthermore, these observations
highlight the need for a global survey of understudied taxa. Since no more than a few percent of goriid
species have been discovered and properly described, the information yet to be revealed about this
enigmatic phylum seems limitless.
280
Removal of the Infective Stages of Giardia and Cryptosporidium Species from Animal Waste Streams
Using Thermophilic Anaerobic Digestion. T.R. RUHNKE*, Department of Biology, West Virginia State
University, Institute WV, USA, and V. CARRASCO, Chapingo University, México.
Previous studies have shown that Thermophilic Anaerobic Digestion (TAD) renders inviable certain
prokaryotic pathogens and helminths. This work centered on the use of a 1-liter experimental anaerobic
digester, and digester effluent incubated in 15 ml centrifuge tubes demonstrates substantially decreased
viability of species in the protozoan genera Cryptosporidium and Giardia. In 20-day feeding experiments,
daily destruction of Cryptosporidium muris oocysts was as high as 96%, and as high as 94% for the cysts
of Giardia muris. Dye exclusion assays indicate the loss of viability for Cryptosporidium parvum and
Giardia lamblia at thermophilic temperatures. Animal infectivity studies were not completely consistent
with the results of the dye exclusion experiments. In addition, Giardia lamblia was more sensitive to the
action of TAD than Cryptosporidium parvum. (Work supported by a USDA administrative grant to West
Virginia State University.)
281
Nematode and Trematode Life Cycle Strategies in Structuring Amphibian Helminth Communities.
M.G. BOLEK* and J. JANOVY, JR., School of Biological Sciences, University of Nebraska, Lincoln NE,
USA.
Previous studies on helminth communities of amphibian hosts indicate that most amphibian parasites are
not host specific and are associated with host habitat. Aquatic amphibian species are dominated by
trematodes, whereas terrestrial amphibian species are dominated by nematodes, and semi-terrestrial
amphibian species are infected with a combination of trematodes and nematodes. Larger individuals and
larger species of amphibians harbor higher helminth species richness and intensities than do smaller host
species. We examined the helminth communities of aquatic, semi-terrestrial, terrestrial, semi-arboreal,
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ABSTRACTS
and arboreal amphibian species from two different ecological habitats differing in their amphibian species
composition and amount of annual precipitation. Our results indicate that in a moist environment
amphibian helminth communities were dominated by trematodes and direct life cycle nematodes that
develop in the soil, whereas amphibian helminth communities in a dry environment were dominated by
trematodes and nematodes that utilize intermediate hosts. In order to understand how amphibians
become infected with different helminth species, we completed the life cycles of three species of trematodes and a two species of nematodes in four and six species of hosts, respectively, to determine their
host specificity and life cycle plasticity. Our study shows that a particular life cycle variant will be favored
by regional environmental conditions and definitive host species composition where factors influence
probabilities of transmission at one or more stages during their life cycle. This conclusion allows us to
generate hypotheses about the mechanisms that drive evolution of parasite life cycles.
282
Larvicidal Potentials of Eucalyptus camaldulensis (Schlect) and Eucalyptus citriodora (Hook) on Culex
quinquefasciatus (Say) Larvae. H.S. IDRIS* and S.B. LAWAL, Department of Biological Sciences,
University of Abuja, Abuja, Nigeria.
The larvicidal activity of leaf and bark extracts of Eucalyptus camaldulensis and Eucalyptus citriodora on
juveniles of Culex quinquefasciatus was determined.One hundred sixty-two batches of 25 larvae each were
treated with 3.90, 15.63, 62.50, 250 and 1000 mg per litre of the plant extract in three replicates, for 24
hours to record mortalities, and for up to 96 hours to record feeding and fecundity of the larvae. There
was an increase in the percentage of mortality with an increase in the concentration in petroleum ether
extract. There was a statistically significant difference between extracts (P < 0.05) used in the bioassay
and mortality of larvae, but there was no significant difference (P > 0.05) between the two plant species
used. Statistical analysis of average mortality figures using the Probit analysis for the extracts gave the L
of 245.47 (26.89 ± SE 10.13) and 316.23 (22.89 ± SE 8.95) for the crude extracts, the petroleum
C50
ether extract had LC50 of 97.72 (44.95 ± SE 12.89) and 223.87 (29.17 ± SE 9.56), methanol extract
LC50 was 162.18 (30.7 ± SE 11.16) and 257.04 (26.47 ± SE 9.28). For the portions, pet-ether portion
had an LC50 of 100.0 (42.17± SE 12.02) and 169.82 (33.67± SE 8.49), methanol portion had an LC50
of 190.55 (30.0 ± SE 9.43) and 398.11 (26.47± SE 9.28). The butanol portion had an LC50 of 416.87
(18.22 ± SE 7.2) and more than 1000 (7.5 ± SE4.59), the aqueous portion had an LC50 of 251.19
(25.36 ± SE 8.98) and 275.42 (23.37 ± SE 9.27) for E. citriodora and E. camaldulensis. The bark
extracts LC50 was 251.19 (27.78± SE 8.39) and 398.11 (20.7 ± SE 7.17) for methanol. Hexane extract
had an LC50 of 302.0 (21.56 ± SE 8.11) and 630.96 (13.56 ± SE 6.4) for E. citriodora and E. camaldulensis. Both plant species exhibited anti-feeding properties against larvae of Culex quinquefasciatus.
283
Schistosome Genetic Diversity and Structuring in a Brazilian Village. E.A. THIELE*, Department of
Biological Sciences, Purdue University, West Lafayette IN, R.E. SORENSEN, Department of Biological
Sciences, Minnesota State University Mankato, Mankato MN, and D.J. MINCHELLA, Department of
Biological Sciences, Purdue University, West Lafayette IN, USA.
The digenean trematode Schistosoma mansoni is responsible for chronic schistosomiasis worldwide, and in
Brazil alone an estimated 35 million people are at risk. In order to evaluate epidemiological patterns
among human definitive hosts, we assessed genetic diversity and population subdivision of S. mansoni
infrapopulations in patients from a highly endemic village in the state of Minas Gerais, Brazil. Parasite
eggs were isolated from fecal samples collected from 30 patients. Following passage through lab-strain
Biomphalaria glabrata snails and BALB/c mice, adult worms were acquired and genotyped at nine
microsatellite loci. Genetic diversity of parasites was relatively high (HS 0.632) and standard measures of
inbreeding indicated that the population is panmictic (FIS -0.008). Furthermore, there was no significant
isolation-by-distance of parasite infrapopulations (r2 0.53, p = 0.25) and measures of population subdivision indicated significant, but very low levels of population partitioning (FST 0.052; F’ST 0.15). We
conclude that patients within this village are sampling a broad range of schistosome genetic diversity and
are effectively acting as ‘genetic mixing bowls’ for the parasites. These results contrast with those previously observed in another Brazilian village, and thus provide the opportunity for comparisons of environ179
ABSTRACTS
mental and epidemiological differences that are likely to influence host–parasite coevolution and parasite
transmission.
284
Molecular Characterization and Evidence of Genetic Exchange in U.S. Isolates of Trypanosoma cruzi.
D.M. ROELLIG*, Department of Infectious Diseases and Southeastern Cooperative Wildlife Disease
Study, Department of Population Health, The University of Georgia, Athens GA, A.W. FUJITA, M.Y.
SAVAGE, Southeastern Cooperative Wildlife Disease Study, Department of Population Health, The
University of Georgia, Athens GA, E.L. BROWN and M.J. YABSLEY, D.B. Warnell School of Forestry and
Natural Resources and Southeastern Cooperative Wildlife Disease Study, Department of Population
Health, The University of Georgia, Athens GA, USA.
Trypanosoma cruzi, the causative agent of Chagas disease, has a broad host and geographic range, leading
to many questions concerning its epizootiology. In particular, it is imperative to understand the association between the genetic type, virulence, and primary reservoir hosts of the parasite. While molecular
characterization of South American isolates of T. cruzi has demonstrated homologous recombination and
nuclear hybridization, as well as the presence of two phylogenetic lineages (Type I and II), few studies
have investigated extensively such exchange events and genetic diversity in North American isolates. In
the current study, we characterized genetically U.S. isolates from wildlife reservoirs (raccoons, opossums,
armadillos, skunks), dogs, humans, nonhuman primates, and reduviid vectors. To determine genotype,
the mismatch repair (MSH2) and glutathione-s-transferase (TC52) genes were amplified and sequenced
from parasite cultures. To investigate genetic exchange, nuclear and mitochondrial gene targets, dihydrofolate reductase-thymidylate synthase and the NADH dehydrogenase subunit I-cytochrome oxidase
subunit II region, respectively, were amplified and sequenced. Sequences were compared to each other
and strains available in GenBank. Initial sequence typing of these genes from selected isolates from five
states (CA, FL, GA, MD, LA) showed single nucleotide polymorphisms and support for the existence of
the two primary genotypes. Upon further investigation of ecologically and geographically distinct T.
cruzi isolates, we expect to observe additional genetic variability between N. and S. American isolates.
Further, confirming previous evidence of a single genetic exchange event in a Florida isolate, we have
observed genetic exchange in several U.S. isolates as demonstrated by incongruent mitochondrial and
nuclear genes phylogenies.
285
Clonal Diversity of the Malaria Parasite, Plasmodium mexicanum: Alterations in Life History Traits,
Virulence and Transmission. A.M. VARDO* and J.J. SCHALL, University of Vermont, Burlington VT,
USA.
Within the vertebrate host, infections of a malaria parasite (Plasmodium)could include a single genotype
of cells (single-clone infections) or two to several genotypes (multi-clone infections). Clonal diversity of
infection plays an important role in the biology of the parasite, including its life history, virulence and
transmission. We determined the clonal diversity of P. mexicanum, a lizard malaria parasite, at a study
region in northern California using variable microsatellite markers, the first such study for any malaria
parasite of lizards. Natural infections captured over a 10-year period (1996–2005) were used to examine
the genetic structure of the parasite metapopulation. Multi-clonal infections were common (50–88% of
infections) at both high- and low-prevalence field sites and heterozygosity estimates were high, even after
a period of overall low prevalence (H = 0.64–0.91). Induced infections were used to examine alterations
in parasite life history traits, virulence and transmission success for single and multi-clonal infections.
Multi-clonal infections produced more gametocytes and at a faster rate than infections harboring a single
genotype (P = 0.04), supporting that established clones compete for transmission opportunities.
Competition for establishment was examined by challenging naturally infected lizards with new parasite
genotypes. Infections with higher gametocytemia (i.e., older infections) were more successful at inhibiting establishment of new clones (P= 0.007). Multi-clonal infections were less virulent than single-clone
infections, having higher glucose and hemoglobin concentrations (P = 0.002 and 0.007, respectively).
Preliminary data on transmission success to the insect vector (Lutzomyia spp.) determined by oocyst
burden on day 5 was greater for single-clone infections than for those harboring three or more clones (P
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= 0.02). These studies suggest that multiple clones within an infection for a malaria parasite results in
complex alterations in life history strategies, virulence and transmission efficiency.
286
Evaluating Whole Genome Amplification for Small Parasites: Typing Hundreds of Microsatellite Markers
from Single Miracidia of Schistosoma mansoni. C.L. VALENTIM*, P.T. LOVERDE, Department of
Virology and Immunology, Southwest Foundation for Biomedical Research, San Antonio TX, T.J.
ANDERSON and C.D. CRISCIONE, Department of Genetics, Southwest Foundation for Biomedical
Research, San Antonio TX, USA.
Obtaining large quantities of DNA from individual parasites is often difficult due to their small size.
Low yields of DNA template preclude the use of multiple molecular markers, thus restricting the types of
questions that can be addressed about the population genetics and epidemiology of parasites. For
example, several studies have genotyped miracidia of S. mansoni to avoid the need for laboratory animals
to acquire adult worms. These studies, however, have been limited to 6–10 microsatellite loci because
DNA is limiting. Furthermore, the genotyping error rate is difficult to assess without the ability to do
repeat genotyping or knowledge of the true genotype. Here, we describe the development of primers for
376 microsatellite loci for S. mansoni and show that these can be genotyped from single miracidia. More
than 90% percent of the first 94 examined amplified cleanly and were highly variable (He = 54–70%) in
studies of adult worms from two strains. To amplify genomic DNA from single miracidia, we used
Multiple Displacement Amplification (MDA), a method that uses the high processivity and fidelity of
phi-29 DNA polymerase and random primers to amplify the entire genome. To investigate the fidelity
with which MDA copies miracidial DNA, we set up a cross between worms from two divergent parasite
isolates, and compared genotypes from single miracidia after MDA with those from parental worms. At
fully informative loci (i.e., no alleles are shared between parental adults), F1 offspring will be heterozygous. Thus, we can test directly the error rate of MDA by genotyping F1 miracidia. Our initial results are
encouraging and suggest that MDA accurately copies DNA, thus allowing genome-wide typing of single
miracidia using hundreds of genetic markers.
287
Modeling of a Potentially Unique Sylvatic Cycle for Trypanosoma cruzi in the Southeastern United
States. E.M. PIERCE*, C.A. HALL, Department of Biology, Berry College, Mount Berry GA, C. KRIBSZALETA, Departtment of Mathematics, University of Texas, Arlington TX, A.N. WIMSATT, J.B. MEERS,
Department of Biology, Berry College, Mount Berry GA, and K. NEWCOMB, Department of Biology,
Centre College, Centre AL, USA.
Although Trypanosoma cruzi is commonly found in sylvatic reservoir species throughout the southeastern
United States, the incidence of autochthonous transmission to humans is rare. Surveys of sylvatic
reservoirs have demonstrated a correlation between host species and the T. cruzi strain, with opossums
(Didelphis virginiana) predictably infected with Type I strains and raccoons (Procyon lotor) with Type IIa.
Despite similar environmental niches and behavior, the prevalence of T. cruzi is frequently higher in
raccoon populations than in opossums from the same area. To test whether vertical transmission may
play a role in this dichotomy, we experimentally tested the ability of different T. cruzi strains to be
transferred from mother to offspring at different rates. In outbred mice, a regional Type IIa isolate was
transferred to 66% of progeny born to infected females, as opposed to 33% of those infected with a Type
I strain. Consistent with theories of virulence management, the Type IIa strain has proven to be of low
pathogenicity, manifesting lower overall replication rates in vitro and in vivo. Infection and challenge
experiments showed that the Type IIa strain also imparted significant protection against challenge with a
more virulent Type I strain. Further support for the likely importance of vertical transmission was found
in vector surveys of areas supporting high T. cruzi prevalence in reservoir populations. An extensive
survey and trapping effort for Triatoma sanguisuga in a peri-domestic site with a 70% prevalence of
infection in the raccoon population failed to provide any evidence of vector presence. We have developed
a novel epidemiological model designed to address the relative contributions of vertical and horizontal
transmission in this potentially unique endemic system.
181
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288
Components of Host Epidermis Reduce Infectivity of Trematode Cercariae. C.T. JAMES*, Department
of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada, B.D. WISENDEN, Biology
Department, Minnesota State University, Moorhead MN, USA, and C.P. GOATER, Department of
Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada.
The epidermal club cells of many Teleost fishes contain specialized epidermal cells that release alarm
substances (e.g., ‘Schreckstoff ’) when damaged. Tests of hypotheses that emphasize the role of alarm
substance as an anti-predator defense have had mixed results. Alternative hypotheses are rarely tested.
Here, we provide an initial test of the hypothesis that alarm substances may play an anti-parasite role.
Most fathead minnows, Pimephales promelas, are exposed to cercariae of the trematode Ornithodiplostomum sp. within their first few weeks following hatching. The cercariae must penetrate the host’s epidermis,
potentially leading to the release of alarm substance. We prepared extracts of minnow epidermis, containing club cells, and exposed cercariae to high and low concentrations of the extract in the laboratory.
Cercariae infectivity was evaluated as the number of metacercariae in the body cavity at four weeks postinfection. Cercariae immersed in the high concentration of skin extract contained 17.0% and 18.1%
fewer encysted metacercariae, respectively, than the control and low concentrations. These results show
that a component of skin extract, possibly released by damaged alarm cells, reduces cercariae infectivity.
289
Detection of Novel Lineages of Malaria Parasites in African Bats. E. STINER, Department of Invertebrate Zoology, American Museum of Natural History, New York NY, USA.
The phylogenetic relationships among malaria parasites from different vertebrate hosts have been
ephemeral from study to study, and there are entire orders of mammals for which phylogenetic relationships of their malaria parasites have not been investigated. For instance, malaria species from chiropteran
hosts have been reported in the literature for nearly as long as the parasites have been known, but their
taxonomy and phylogenetic relationships within the group has garnered relatively little attention from
parasitologists. Previous treatments based on morphology grouped bat malaria parasites into four natural
genera: Plasmodium, Nycteria, Polychromophylus and Hepatocystis. The present study screened tissue
samples from bats that had been collected in the Central African Republic with malaria parasite-specific
primers. Phylogenetic analyses using sequences of the cytochrome b, cytochrome oxidase I and clpc
genes of these eight chiropteran parasites along with 20 additional parasites from rodent hosts were
performed. The analyses yielded two broad clades, one that grouped with rodent Plasmodium species and
one that was similar to previously reported primate and bat Hepatocystis parasites. These findings bring
into question the validity of previous taxonomic designations and the monophyly of malaria clades that
have been based traditionally on morphology and host specificity. These results also suggest that at least
one host switch between rodents and bats has occurred.
290
Immunization of Goldfish with Recombinant Parasite β-tubulin Confers Protection Against trypanosoma Danilewskyi Infection. B.A. KATZENBACK*, Department of Biological Sciences, University of
Alberta, Edmonton, Alberta, D.A. PLOUFFE, NRC, Institute for Marine Biosciences, Halifax, Nova
Scotia, G. HADDAD and M. BELOSEVIC, Department of Biological Sciences, University of Alberta,
Edmonton, Alberta, Canada.
Trypanosoma danilewskyi (syn T. carassii) is a blood-borne protozoan parasite of bony fishes that is transmitted by freshwater leaches. While T. danilewskyi is not highly pathogenic, the prevalence in aquaculture
settings can reach 100% as a result of stress induced by crowding, causing high mortality in fish. Longterm resistance of the fish to secondary infection with T. danilewskyi is antibody-mediated, since passive
transfer of immune serum or IgM from previously infected fish protected naïve fish from a challenge
infection. This study focused on identifying key parasite antigens responsible for eliciting a protective
antibody response. Previous experiments in our lab have shown that immunization with parasite excretory–secretory (E-S) products conferred significant protection against infection. We found that the major
antigen in the E-S of T. danilewskyi was tubulin, which is the structural component of microtubules in
eukaryotic cells. We cloned, sequenced and expressed recombinant α- and β-tubulin of T. danilewskyi
182
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using a prokaryotic expression system, and produced affinity-purified rabbit anti-tubulin IgG, which
recognized both α- and β-tubulin in a Western blot and ELISA. The exposure of cultured trypanosomes
to different concentrations of anti-tubulin IgG caused significant dose-dependent lysis of the parasites in
vitro. Goldfish immunized with 40 or 80 µg of β-tubulin were significantly protected against a challenge
infection. Immunized fish had significantly lower (> 2.5 log) parasitemia on days 3 and 7 after challenge, which was related to the anti-tubulin antibody response in immunized fish. Our findings indicate
that one of the major antigens of T. danilewskyi is tubulin and that fish are capable of mounting a protective antibody-mediated response against this infection.
291
Humoral Antibody Response of the Tilapia Oreochromis niloticus Against Cichlidogyrus spp. J.J.
SANDOVAL-GÍO*, R.D. RODRÍGUEZ-CANUL and V.M. VIDAL-MARTÍNEZ, Laboratorio de Inmunología y Biología Molecular, Departamento de Recursos del Mar, CINVESTAV, Mérida, Yucatán, México.
The humoral immune response of the tilapia, Oreochromis niloticus, was evaluated using a direct ELISA
with sera from fishes infected with Cichlidogyrus spp., sera from non-infected fishes and from fishes
injected intraperitoneally with the Cichlidogyrus spp. antigenic extract: 150 µl of the Cichlidogyrus spp.
saline extract diluted in Freund´s complete adjuvant (1:1) were inoculated intraperitoneally at day 0,
followed by two dosages of 50 µl of the same Cichlidogyrus spp. saline extract diluted in Freund’s incomplete adjuvant (1:1) at wk 2 and 4, respectively. This humoral response also was evaluated by the Double
Immunodiffusion Test (DID) and by serum protein and Total Immunoglobulins (Ig’s) determinations.
The IgM OD values in the hyper-immune fishes were significantly higher than in the infected and noninfected fish groups. In the DID test, a precipitation (antigen–antibody) band was observed between the
Cichlidogyrus spp. saline extract and the hyper-immune sera, but not with the other groups. Increases in
serum protein concentration and Total Ig’s were observed at wk 2 and 10 post-injection in the immunized fish. Results from this study suggest that tilapia is capable of producing an induced humoral
immune response against an antigenic extract of Cichlidogyrus spp.
292
First Report on Population Structure for the Leishmania major Vector, Phlebotomus papatasi Sandfly,
Using Microsatellite Loci. O. HAMARSHEH*, W. PRESBER and G. SCHÖNIAN, Institut für Mikrobiologie und Hygiene, Humboldt Universitaet, Charité Universitätsmedizin, Berlin, Germany.
Although many methods have been applied so far to characterize populations of Phlebotomus papatasi
sandfly, still their genetic structures are not well understood. This widely distributed sandfly species is the
principal vector of Leishmania major, which causes cutaneous leishmaniasis in the Old World. Multilocus
microsatellite typing (MLMT) was used to infer population structure of these sandflies and assign
individuals to populations. This approach used five microsatellite loci and 188 P. papatasi individuals
originating from 35 populations distributed in 15 countries. Unique microsatellite signatures were
observed for some populations analyzed and 114 different genotypes were found in total. Analysis of the
data set showed comparable results using model and distance-based methods. Individual-based analyses
split the data set into two distinct genetic clusters; ‘A’ and ‘B,’ with further sub-structuring among each.
Within ‘A’ group, five sub-groups had geographical correlations with large numbers of alleles. The genetic
differentiation (FST) of the five sub-groups within ‘A’ cluster ranged from 0.816 to 0.403. The degree of
genetic isolation was relatively high and statistically significant (P < 0.005). There was no correlation
between linearized genetic distance and geographic distance as a whole. Understanding the genetic
structure of P. papatasi populations is important for the implementation of efficient measures for sandfly
control.
293
Probiotics: Is This the Way of the Future in Coccidiosis Control? J.L. McPHERSON-KOMOROWSKI*
and J.R. BARTA, Department of Pathobiology, The University of Guelph, Guelph, Ontario, Canada.
Coccidiosis is a major parasitic disease of poultry caused by protistan parasites that invade and inhabit
the gut. Probiotics (defined or undefined commensal enteric bacteria, e.g., lactobacilli) could contribute
to successful coccidiosis control since microflora are an important first line of defence against enteric
infections. To assess this, groups of chickens were orally challenged with E. tenella and were either
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ABSTRACTS
administered a probiotic or sham inoculated. Growth rate and food conversion efficacy of the birds was
calculated over the challenge period and lesions resulting from the parasite were scored blindly using a
qualitative scale. Messenger RNA was isolated from cecal tonsils and spleen to detect differences in
cytokine gene expression to characterize the nature and intensity of any immune response. These experiments will examine the complex interactions among protistan pathogens, beneficial gut microflora and
the immune system of the chicken and may lead to more successful and widespread use of live coccidiosis
vaccines in the broiler industry, thereby reducing the industry’s reliance on in-feed prophylactic medications.
294
RNA Polymerase III Transcription Complex in Leishmania major. S. MARTÍNEZ-CALVILLO*, UBIMED,
FES Iztacala, UNAM, Tlalnepantla, Edo. de México, México, P.J. MYLER, Seattle Biomedical Research
Institute, Seattle WA, USA, L.E. FLORENCIO-MARTÍNEZ, D.E. VELEZ-RAMIREZ, C. FLORES-PÉREZ
and E.E. FIGUEROA-ANGULO, UBIMED, FES Iztacala, UNAM. Tlalnepantla, Edo. de México, México.
Leishmania and other members of the Trypanosomatidae family possess distinctive mechanisms of gene
expression, such as polycistronic transcription and trans-splicing. Although transcription initiation has
been studied extensively in this group of parasites, the process is still poorly understood. Even though all
the subunits that are common to the three RNA polymerases (Pol) have been identified by in silico
analysis, some of the polymerase-specific subunits have not been found. Moreover, most of the general
transcription factors have not been identified in trypanosomatids, which indicates either that they are not
present or that their sequences have diverged considerably. Our research interest is focused mainly in the
study of transcription by Pol III, involved in the synthesis of small essential RNAs, like tRNAs, 5S
rRNA and snRNAs. In order to identify the components of the Pol III transcription complex in L. major,
we performed the Tandem Affinity Purification (TAP-tag) method. The experiments were performed
using one of the two isoforms of ABC23 present in L. major as a target. Mass spectrometry analyses of
the purified complexes led to the identification of 11 different Pol III subunits, as well as several other
proteins of unknown function. To try to identify other components of the Pol III complex, currently we
are making new TAP-tag constructs with Pol III-specific subunits and putative transcription factors. In
some of the vectors, we are using a new tag, the PTP-tag, which is reported to improve the amount of
purified proteins.
295
Monoxenic Growth of Entamoeba histolytica with Escherichia coli 055 Modulates Amoebic Virulence
and Gene Expression. C.L. MENDOZA-MACÍAS*, M.P. BARRIOS-CEBALLOS, L.P. CÁRDENAS-DE LA
PEÑA, F. ANAYA-VELÁZQUEZ and F. PADILLA-VACA, Instituto de Investigación en Biología Experimental, Facultad de Química, Universidad de Guanajuato, Guanajuato, Gto, México.
E. histolytica is the causative agent of amoebiasis, an invasive disease that mainly affects intestinal and
occasionally extra-intestinal tissues. The E. histolytica virulence has been related to a number of amoebic
components such as lectins, cystein proteinases and amebapore. The relative virulence of different strains
of E. histolytica has been shown to vary as a result of changes in conditions of in vitro cultivation, and it is
possible that some virulence factors are expressed only during exposure of the parasite to the host factors
such as bacterial flora. A number of studies suggest that the amoebae–bacteria association has a profound
effect on the amoebic behavior, which ultimately influences its virulence properties. As was reported
previously, we found that E. histolytica trophozoites grown on monoxenic culture with E. coli serotype
055 lose their virulence, and it is recovered after several months of growth with the same bacteria;
meanwhile, short-term interaction with the same E. coli cells increase the cytophatic activity of this
parasite. In order to identify genes that are expressed differentially in E. histolytica strain HM1:IMSS as a
consequence of monoxenic growth with E. coli, the GeneFishing® technology was used. PCR amplification using a number of arbitrary oligonucleotides resulted in the detection of differentially amplified
fragments ranging between 150 to 800 bp. The results indicate that some differentially expressed genes
codifying for metabolic enzymes, ribosomal proteins, transcription factors, and molecules related with
virulence. Macroarrays constructed with this genes collection show that they are differentially expressed.
The identification of those genes opens the way for further study of molecular mechanisms controlling
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ABSTRACTS
gene expression related with the amoebae–target cells interactions and help to decipher the cross talk
between E. histolytica trophozoites and the host factors that ultimately either trigger or prevent disease.
296
Babesia bovis Merozoites and Kinetes Differentially Express MSA-2c and HSP-20. J. MOSQUEDA*,
CENID-PAVET-INIFAP, Jiutepec, Morelos, Y. RIVERA, College of Biological Sciences, Autonomous
University of Morelos State, Morelos, A. FALCON, J.A. RAMOS, J.V. FIGUEROA, J.A. ALVAREZ, CENIDPAVET-INIFAP, Jiutepec, Morelos, México, J. NORIMINE and W.C. BROWN, Department of Veterinary
Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman
WA, USA.
Bovine babesiosis caused by B. bovis is an important disease of cattle in the Americas because of the costs
associated with death, control and treatment measures. Heat shock protein 20 (HSP-20) and merozoite
surface antigen 2c (MSA-2c) are two proteins considered as candidates to be included in vaccines or
diagnostics methods for the control the disease. Expression of hsp-20 and msa-2c have been shown in
sporozoites and merozoites of Babesia bovis, suggesting that both genes have a function in the cellular
physiology of erythrocyte-infecting stages. It is not known if they are expressed and therefore have a
functional role in tick stages, specifically kinetes. The objective of this work was to analyze whether HSP20 and MSA-2c are expressed in kinetes of B. bovis. Kinetes were obtained from the hemolymph of R.
microplus females seven days after feeding on a B. bovis-infected bovine. For the transcription analysis,
cDNA was analyzed by PCR with specific primers for hsp-20 or msa-2c. Expression analysis was carried
out using western blot and indirect immunofluorescence (IFAT) with an antibody against a synthetic
peptide from HSP-20 and an antibody against recombinant MSA-2c. Results obtained by RT-PCR
showed amplicons of the expected size and sequence for hsp-20 in kinetes, as well as for erythrocytic
stages used as positive control. No transcription was observed for msa-2c when cDNA from kinetes was
analyzed compared with merozoites used as control. A positive band of the expected size was detected by
western blot when kinetes were analyzed with specific antibodies for HSP-20; positive signals also were
detected by IFAT for HSP-20 in intraerythrocytic stages. No band was observed by western blot when
anti-MSA-2c anti-antibodies were incubated with kinete proteins or by IFAT. Positive signals were
observed by western blot and IFAT in merozoites used as controls. This is the first report of a differential
transcription and expression of any Babesia gene, and suggests that MSA-2c could only be important
during the erythrocytic cycle, emphasizing its role during invasion.
297
Ancylostoma Caninum DAF-16 Binds to a Conserved DAF-16 Family Member-binding Element. X.
GAO and J.M. HAWDON*, Microbiology Immunology and Tropical Medicine, The George Washington University Medical Center, Washington DC, USA.
The Forkhead/FOXO transcription factor DAF-16 plays an essential role in the regulation of development in the free-living nematode Caenorhabditis elegans. In response to adverse environmental changes,
DAF-16 enters the nucleus and positively regulates genes involved in the formation of the developmentally arrested dauer larva. Insulin-like signaling in response to improved conditions negatively regulates
DAF-16, resulting in resumption of reproductive growth. The infective third stage larva (L3) of hookworms is remarkably similar to the developmentally arrested dauer stage of C. elegans. DAF-16 orthologs
have been identified and sequenced from Ancylostoma caninum and A. ceylanicum. We hypothesized that
Ac-DAF-16 would bind to the C. elegans conserved DAF-16 binding element (DBE) to regulate hookworm gene transcription. The entire coding sequence of Ac-DAF-16 was cloned into a mammalian
expression vector to generate pCMV4-Daf16, and the FLAG tagged recombinant DAF-16 (rDAF-16)
expressed in HEK293T cells. Western blots of cell lysates probed with anti-FLAG antibody and Ac-DAF16 antiserum confirmed DAF-16 expression. A streptavidin bead pull-down assay was performed to
investigate the interaction between the recombinant Ac-DAF-16 and the biotin-labeled DBE. Recombinant DAF-16 strongly bound to the C. elegans DBE, and more weakly to a DBE-like sequence located in
the promoter of the Ac-dao-1 gene, which encodes an ortholog of a C. elegans FKBP-like protein.
Recombinant DAF-16 failed to pull-down a labeled random primer, indicating that the interaction with
DBE is specific. Additional experiments to determine if rDAF-16 can drive expression from the DBE
promoter sequence are underway. Our data indicate that Ac-DAF-16 interacts with the conserved DBE,
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ABSTRACTS
and will allow us to identify DAF-16 regulated genes in hookworms. (Supported by NIAID
5R21AI062857.)
298
Changes in Expression of Heat Shock Response Genes During Ancylostoma caninum Larval Activation.
A. LORSONG, X. GAO, L. JENNELLE, A. DELANEY and J.M. HAWDON*, Microbiology Immunology
and Tropical Medicine, The George Washington University Medical Center, Washington DC, USA.
During infection, third stage larvae (L3) of hookworms undergo a temperature shift between the
environment and the host. This temperature change can be large, and may stimulate a heat shock response (HSR) in L3. Using an in vitro activation assay, we examined the expression of six HSR genes
(heat shock proteins 90, 70, 12.6, 16.1, 16.49, and heat shock binding protein) by real time PCR over
the course of activation of Ancylostoma caninum L3. About 15,000 L3 non-activated (NA, RPMI medium alone) and activated (ACT, serum filtrate + S-methylglutathione) were incubated at 37°C, 5% CO2
for 2, 6, 12, and 24 hrs. Untreated L3 were maintained at 22°C. Total RNA was isolated, and mRNA
converted to cDNA using Super SMART™ PCR cDNA Synthesis Kit. Primer sets amplifying 200–300
bp fragments were designed for each gene, and expression levels determined using SYBR Green qPCR.
Target concentration in each template was determined from standard curves using plasmids containing
the cloned amplicon. Concentrations were normalized to starting cDNA concentration, and the fold
change from untreated cDNA calculated. Results indicate that hsp-70 is down-regulated nearly threefold, and hsp-90 almost two-fold, in both NA and ACT L3 by 2 hrs incubation, and levels remain low
through 24 hrs. Transcript levels of the small heat shock protein hsp-12.6 are down-regulated almost
four-fold by 2 hrs, and remain down-regulated, in ACT L3 compared to untreated, but levels are unchanged in NA L3. Transcripts of heat shock binding protein (HSB-1), a negative regulator of the HSR
in C. elegans, remain unchanged in ACT L3, but are down-regulated two-fold at 12 and 24 hrs of
activation. In L3 exposed to a 43°C heat shock for 1 or 3 hrs, hsb-1 transcripts are down-regulated more
than two-fold, and hsp-12.6 levels are down-regulated more than three-fold. Hsp-70 levels are slightly
elevated and hsp-90 levels slightly down-regulated, by at 3 hrs of heat shock. While expression of some
hsps mimic changes that occur during heat shock, our data suggest that activation does not fully stimulate the HSR. (Supported by NIAID 5R21AI062857.)
299
Babesia bagemina Glycoprotein 45: In silico Comparative Analysis of a Vaccinal Strain and Field Isolates
from México and Argentina. J. MOSQUEDA*, CENID-PAVET-INIFAP, Jiutepec, Morelos, L.A. CASTRO,
Facultad de Ciencias Agropecuarias, Universidad Juarez Autónoma de Tabasco, Tabasco, A. FALCON,
J.A. RAMOS, CENID-PAVET-INIFAP, Jiutepec, Morelos, D. BENITEZ, E. ALCARAZ, EEA-Mercedes;
INTA, Mercedes, Corrientes, Argentina, J.V. FIGUEROA and J.A. ALVAREZ, CENID-PAVET-INIFAP,
Jiutepec, Morelos, México.
In the Americas, bovine babesiosis is caused by two species: Babesia bovis and Babesia bigemina. Although
B. bovis is traditionally considered more important, B. bigemina can cause acute disease, too, characterized
by the presence of hemoglobinuria and hemolytic anemia. To date, there is no synthetic vaccine against
bovine babesiosis, and it has been hypothesized that this vaccine should include Babesia antigens located
on the surface of the parasite. In B. bigemina, there are two reported glycoproteins and of these two, a
glycoprotein of 45 (GP45) kilodaltons is the most studied. GP45 is exposed on the surface of merozoites
and it has been proposed that it has a role in erythrocyte invasion. However, it is not a conserved protein
showing genetic and antigenic polymorphism. Despite the high degree of variability for this protein in
isolates from different parts of the world, the degree of variability or conservation of GP45 within
endemic regions in the same country is unknown. Knowing the extent of conservation or variability of
this protein at the level of regions or within countries is important because it allows us to predict the
success of a future synthetic vaccine based on these type of antigens in those regions or countries.
Consequently, the objective of this work was to isolate, sequence and compare the gen gp45 of B. bigemina as well as the predicted protein sequence in seven strains and isolates: five field isolates (Veracruz,
Nayarit, Jalisco, Guerrero and México) and a vaccinal (Seed) strain from México, and a field strain from
Argentina (Corrientes). The comparative nucleotide and amino acid sequence analysis revealed a high
percentage of homology between the vaccinal strain and the Argentinean and Mexican field strains. There
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was no phylogenetic relationship between isolates geographically closer or between the vaccinal and the
virulent México strains. These results, although preliminary, suggest that GP45 is not as variable as
thought before; therefore, it should be considered when developing control tools against bovine babesiosis.
300
Serial Analysis of Gene Expression (SAGE) Identifies Stage-associated Gene Transcripts During Larval
Schistosoma mansoni Larval Development. A.S. TAFT* and T.P. YOSHINO, PBS, University of Wisconsin, Madison WI, USA.
The transformation of the free-swimming miracidia stage to the molluscan sporocyst stage is associated
with a multitude of gene expression changes and alterations in parasite morphology and physiology. Our
goal is to determine genes involved in the penetration, transformation and growth of larval schistosomes.
We have utilized SAGE to assess transcriptional changes during larval schistosome development. SAGE
provides a snapshot of mRNA populations in a given sample. Short sequence tags (21 nt) are generated
and mapped to a unique position on an mRNA. The source gene can be identified by the tag sequence
and the transcriptional abundance can be measured by the amount of times this tag appears in a given
sample. This technique requires no a priori knowledge of expressed genes in a given sample. In addition,
previously unknown genes may be identified and isolated using the sagetag sequence. SAGE analysis was
performed on miracidia, and 6-and 20-day in vitro cultured sporocysts. Miracidia associated gene transcripts include some previously described soluble egg antigens (SEA), genes with unknown functions
and some unknown gene transcripts. SEA gene transcripts associated with miracidia include SME16 (a
16kDa calcium binding protein), phosphoenolpyruvate carboxykinase (PEPCK), p40 egg antigen (a
small heat-shock like protein with two alpha-crystallin domains) and IPSE/Alpha-1 (a glycoprotein
carrying the Lewis-X motif). We will focus on SME16, a previously described protein containing four efhand calcium binding domains. SME16 transcript abundance rapidly decreases in newly hatched and
actively transforming miracidia. A recombinant protein has been expressed and polyclonal antibodies
have been generated. Protein expression has been assessed and immunocytochemistry has localized the
protein in the miracidia and developing sporocyst.
301
Molecular Evidence of Perkinsus marinus in the Eastern Oyster Crassostrea virginica from the Gulf of
México. J.P. EK-HUCHIM*, R. RODRÍGUEZ-CANUL, R. VARELA-VALENCIA, V.M. VIDAL-MARTÍNEZ,
R. SIMÁ-ÁLVAREZ and L. AGUIRRE-MACEDO, Laboratorio de Inmunología y Biología Molecular,
CINVESTAV-IPN, Unidad Mérida,Yucatán, México.
The eastern oyster Crassostrea virginica is one of the major mollusc resources from the Gulf of México;
the protozoan Perkinsus marinus has been reported as the most important pathogen for this resource. P.
marinus has been studied since it was first reported in 1949 in oysters from the Chesapeake Bay, USA. It
is widespread and, since 1974, it has been reported from the Mexican coast of the Gulf of México to the
Yucatán Peninsula. In previous studies, P. marinus was detected by histology and by the Fluid Thioglycollate Medium (FTM). These techniques have proven to be effective for the detection of P. marinus.
Their sensitivity and specificity, however, can be variable and sometimes lower than 50%. Apart from
that, their performances are time consuming and they cannot distinguish among several species of
Perkinsus. In this paper, we standardized a PCR specific for P. marinus and then compared it with the
FTM in oysters collected in Tabasco Lagoon, México and in Terminos Lagoon in Campeche. In Tabasco,
the sensitivity of the PCR was 98.7% and 85.3% for TTM; the specificity was 100% and 78%, respectively. In Terminos Lagoon, the sensitivity of the PCR was 100% and 11% for TTM; the specificity was
100% and 32%, respectively. PCR can be useful to detect P. marinus in cultured areas.
302
Anthelmintic Effects of Tannin-rich Plants on Parasitic Nematodes of Small Ruminants: Possible Modes
of Action Against the Infective Third-stage Larvae. H. HOSTE*, S. BRUNET, INRA/DGER, Ecole Nationale Vétérinaire de Toulouse, Toulose, France, I. FOURASTE, IRD/UPS Faculté des Sciences Pharmaceutiques, Toulouse, France, G. VILAREM, INRA/ENSIACET, Tolouse, France, F.J. JACKSON, Morendun
Research Institute, Bush Loan, Penicuik, Edinburgh, U.K. M.A. ALONSO-DÍAZ, and F.J. TORRES187
ABSTRACTS
ACOSTA, Faculdad de Medicina Veterinaria y Zootecnia, Univerisdad Autónoma de Yucatán, Mérida,
Yucatán, México.
The search for alternative solutions to chemical treatments has been prompted by the rapid emergence
and widespread diffusion of resistance to anthelmintics in populations of gastrointestinal nematodes in
sheep and goats. Nowadays experimental evidence is accumulating to suggest that tannin-rich plants
have anthelmintic properties and thus may represent a possible alternative option for the control of
nematodes. However, a better understanding of the mode of action of tannins against the parasites is
required to permit the pertinent application of these nutraceuticals in farm conditions. Results from both
in vitro and in vivo studies using tropical and/or temperate tanniniferous plants will be presented to
illustrate the effects on the initial stage of host infection, i.e., the establishment of third-stage larvae (L3).
The hypothesis that tannin-rich extracts interfere with the two successive biological larval processes that
are crucial to successful host invasion will be discussed, based on recent experimental data obtained in
vitro and/or in vivo. The first key process liable to disruption is the exsheathment of infective third-stage
larvae, and the second is the ability of those exsheathed larvae to closely associate with the mucosal
surface and enter into the digestive mucosae.
303
An Overview of Parasitological Research on the Spotted Rose Snapper, Lutjanus guttatus: Implications
for Aquaculture in México. E.J. FAJER-ÁVILA*, F. GARCÍA-VARGAS, R.M. MEDINA-GUERRERO,
Laboratorio de Parasitología, and M. BETANCOURT-LOZANO, Laboratorio de Ecotoxicología, Centro
de Investigación en Alimentación y Desarrollo, A.C, Unidad Mazatlán en Acuicultura y Manejo
Ambiental, Sinaloa, México.
The recent technological advances regarding the culture of the spotted rose snapper, Lutjanus guttatus,
have shown that this fish species could be a promising aquaculture candidate in México. However,
parasites pose a real, yet unquantified, risk for the culture of this species. Forty parasites species (four
protozoans, 33 helminthes and three crustaceans) have been found on wild and cultured fish. The
protozoans Amyloodinium ocellatum, Cryptocaryon irritans and Brooklynella hostilis resulted pathogenic for
snappers cultured in tanks, causing high mortalities, spreading their distribution and impact, and hampering their control. The most prevalent and abundant monogeneans belong to the family Dactylogyridae (genus Haliotrema and Euryhaliotrema), infect gills, and result in epithelial hyperplasia of gill lamellae
and anorexia. Others monogeneans, such as the capsalid Neobenedenia sp, recently was observed causing
hemorrhage of the caudal fin, emaciation and mortality in juveniles reared in tanks, whereas Microcotyloides incisa was observed frequently on wild fish. The copepods Lernanthropus sp. and Caligus sp.
were present at low levels on both wild and floating cage cultured fish. The effectiveness of different
chemicals and naturals treatments against protozoan and monogenean parasites using in vitro and in vivo
assessments has been evaluated. Repetitive freshwater and formalin baths were effective against B. hostilis
and dactylogyrid adults, but also removing trophonts of A. ocellatum, which allowed the control of mixed
infections by protozoan and monogeneans. Sodium hypochlorite completely suppressed the viability of
dactylogyrids eggs. Praziquantel baths showed the strongest effect against dactylogyrid species, but their
use in floating cages is impractical due to costs and possible environmental contamination. Research
continues to evaluate the effect of therapeutic alternatives such as praziquantel, garlic and immunostimulators orally administered aimed at implementing the most environmentally friendly practices
against the most pathogenic parasites.
304
Novel Bencimidazole Derivates Against Toxocara canis Second-stage Larvae and Hymenolepis nana. A.
MÁRQUEZ-NAVARRO*, Departamento de Parasitología, Escuela Nacional de Ciencias Biológicas, IPN,
México DF, J.P. MARTÍNEZ-LABAT, Laboratorio de Parasitología, UNAM, FESC, México, B. NOGUEDATORRES, Departamento de Parasitología, Escuela Nacional de Ciencias Biológicas, IPN, México DF,
M.A. HERNÁNDEZ-CAMPOS, Departamento de Farmacia, Facultad de Química, UNAM, CU, México
DF, L. YÉPEZ-MULIA, Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias,
IMSS, México DF, R. CASTILLO-BOCANEGRA and F. HERNÁNDEZ-LUIS, Departamento de Farmacia,
Facultad de Química, UNAM, CU, México DF, México.
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ABSTRACTS
Helminth parasites infect a quarter of the world’s total population, and are a major cause of morbidity
and the most important cause of productivity losses in livestock worldwide. The discovery of broadspectrum anthelmintic activity associated with different 2,5-disubstituted benzimidazoles is a landmark
in the chemotherapy of parasitic diseases. A requirement for their action is that the substituted benzimidazole bears a hydrogen atom at the 1-position and a methylcarbamate group at the 2- position. In order
to obtain information about the structural requirements for antiparasitic activity, one set of benzimidazole derivatives has been developed against Toxocara canis and Hymenolepis nana. Compounds 4-9 were
designed as albendazole prodrugs without hydrogen at 1-position. Compound 11 was designed as
triclabendazole bioisoster. Compounds 10, 12-14 were prepared as 11 analogues. Compound 10 and 11
have a SH and CF3 instead SCH3, respectively. Compound 13 and 14 have a methyl group at 1-position,
but 14 has 2-naphtol at 5-position instead of 1-naphtol. Compounds 15 and 16 were designed as proalbendazole. All compounds (range 100–0.01 µg/mL) were assayed on T. canis J2 stage in 96 wellculture plates at 37ºC/24 h with RPMI 1640, and the biological activity was evaluated using the Relative
Motility (RM) criteria. Mice were infected with 800 H. nana eggs by the oral route. They were treated
with a dosage of 160 mg/kg for three consecutive days. The mice were sacrificed at 10 days after the
treatments, and H. nana adults in gut were counted. Prodrugs 15 and 16 did not exert biological activity
against T. canis and H. nana. Compounds 10, 11 and 14 (non-carbamates) had a significantly weak
activity compared with albendazole (RM 20%). Compound 9 were the most active against T. canis (RM
70%), followed by the 7, although without parasiticide effect. Compounds 10 and 13 (non-carbamates)
were active on H. nana, reducing the number of adults (80 and 79%, respectively). Conclusion: three
novel benzimidazole derivatives with anthelmintic activity against T. canis and H. nana were developed.
305
New Nitroderivates Against Trypanosoma cruzi Trypomastigotes. J.C. VILLALOBOS-ROCHA*, B.
NOGUEDA-TORRES, A. MÁRQUEZ-NAVARRO, Departamento de Parasitología, Escuela Nacional de
Ciencias Biológicas, IPN, México DF, and E. CORTÉS-CORTÉS, Instituto de Química, UNAM, CU,
México DF, México.
Trypanosoma cruzi is the protozoan parasite that causes Chagas disease. The drugs most frequently used
for the treatment of Chagas disease are nitroheterocyclic compounds: nitrofuran (nifurtimox) and
nitroimidazole derivative (benznidazole). Treatment options for T. cruzi infections are suboptimal due to
their toxicity and the presence of resistant strains. For the above-mentioned, 10 new derivates were
developed from 1-{[(5-R1-tiophen)-2-il]-methylen}-2-(o;p-R2) phenyl hydrazone with structural
similarities to Nifurtimox, and their in vitro activity was evaluated against blood trypomastigotes, with
the aim of keeping their parasitic action and diminishing collateral effects. All derivates bear different
moieties such as chlorine, bromine, fluorine, NO2 and hydrogen in R2 position; five derivates bear a
nitro (NO2) group and five with hydrogen in R1 position. Two T. cruzi Mexican strains (NINOA and
INC.5) were used. Blood trypomastigotes (1 x 106 parasites/mL) were placed in 96-well plates with the
corresponding compounds and were maintained at 4°C for 24 hours. The lysis of trypomastigotes was
determined as a percentage compared with the negative controls. The NINOA strain was more sensitive
to the reference drugs, compounds with the best trypanocide activity against INC-5 strain, bear hydrogen and halogens. Compounds with the best tripanocidal activity for the NINOA strain bear hydrogen
and bromine; the compound that bears hydrogen in R1 and Br in R2 showed the best trypanocidal
activity in both stains. Thus, we conclude that the presence of the group NO2 in the phenyl hydrazone
derivates developed is not necessary to obtain a trypanocidal effect.
306
Anthelmintic Activity of Nine New Synthetic Derivatives of 4-Hidroxiphenil Ethyl Carbamate Chemicals
Against Haemonchus contortus: An in vitro Model. J.P. MARTÍNEZ-LABAT*, Laboratorio de Parasitologìa, Facultad de Estudios Superiores Cuautitlàn, UNAM, E. ANGELES-ANGUIANO and N. PERERIRAZULUAGA, Nacional Autònoma de Mèxico, México.
This work identified antihelmintic activity of nine synthesis products of 4-hidroxifenil ethyl carbamate in
an H. contortus model. For this purpose, H. contortus eggs were obtained from induced infested ovines.
The eggs were recovered from supernatant and centrifuged with saline solution for immnediate use. Each
assay was done in a 12-well poliestirene plate, placing 200 µl of physiological saline solution containing
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ABSTRACTS
100 H. contortus eggs plus 40 µl of each chemical, using concentrations of 5, 10, 20, 50 and 100 mg/ml
for each one. All aliquots were added with 160 µl of a bacterial suspension derived from mouse feces.
Albendazole at concentration of 20 mg/1000 ml and water as a negative control were included in each
assay. The plates were incubated for four days in a humid chamber. Each assay was performed in triplicates as described by Ibarra and Jenkins (1984). The codes of the chemicals tested are: IRE1A, IRE2A,
IRE2B, IRE5A, IRE6A, IRE6B, IRE7B, IRE8A and IRE8B. The samples were evaluated during four
days at 10x using an optical microscope to record the development and hatching of the larvae stages in
order to stablish an inhibition percentage (dead eggs). The main inhibition percentage were: 88.7% for
IRE1, 88.3% for IRE2A, 89.4%, for IRE2B, 91.1% for IRE5A, 92% for IRE6A, 90.1% for IRE6B,
91.9% for IRE7B, 93% for IRE8A and 91.7% for IRE8B at a concentration of 5 mg/kg. A 100%
inhibition in the remaining concentrations from all chemicals tested was found. The albendazole control
showed 98.8% inhibition, while in the water negative control, only the 5.4% inhibition was observed.
The data were analyzed with an hypothesis test (α = 0.05) for independent sample differences among
media. A critical value of Z = 1.96 was obtained and the calculated value for the concentration of 10
mg/ml from all chemicas tested was of 2.8998, which showed a significant difference. Taken together, the
findings confirmed antihelmintic activity of the nine chemicals tested, with a 100% inhibition from the
concentration of 10 mg/ml.
307
Effect of Different Ivermectin Dosages on Encysted Larvae of Toxocara canis in White Mice. J.P.
MARTÍNEZ-LABAT* and N. ACOSTA-SEVILLA, Laboratorio de Parasitologìa, Facultad de Estudios
Superiores Cuautitlàn, UNAM, México.
Toxocariosis is a common intestinal nematode in puppies with extraintestinal larvae forms in adult dogs
that is transmitted easily to other animals and humans. Ivermectin has been used indiscriminately against
this nematode and other parasites since the 1980s in dogs. Taking into account the impact this parasite
has on animal health, its zoonotic potential, and the fact that currently there is no active chemical with
the capacity to eliminate larvae phases 100%, this study evaluated the performance of single, increasing
dosages of ivermectin against encysted larvae of T. canis. For this purpose, 72 CD-1 male white mice
were distributed randomly into eight groups of nine mice each. Six groups were infested with 500 larvae
eggs by gastric gavage and the remaining two groups were uninoculated. Thirty days post-inoculation,
four groups were administered with single, increasing dosages of ivermectin as follows: 4 mcg/kg (Group
1), 50 mcg/kg (Group 2), 800 mcg/kg (Group 3), and 1000 mcg/kg (Group 4). The remaining inoculated groups were treated with ivermectin vehicle (6:4 propilenglicol–glicerinformal) or left untreated
(Groups 5 and 6, respectively). Groups 7 and 8 were used as non-inoculated, non-treated controls.
Thirty days post-treatment, groups 1–7 were euthanized and dissected to obtain samples of kidney, liver,
heart, lungs brain and 1g of striated skeletal muscle. The tissues samples were digested to quantify larvae
microscopically. In brain and muscle, the larvae decreased in an orderly fashion as the dosages increased.
The lowest efficacy levels were at 4 and 50 mcg/kg dosages (11.83% and 20.34%, respectively), which
are below the regular standard dosages (200 mcg/kg). The most efficient dosages were seen at 400, 800
and 1,000 mcg/kg, which decreased the larvae findings 51.34%, 61% and 68.74%, respectively. The
brain and muscle values were found statistically significant, showing in a direct fashion dosage/efficacy. It
is important to stress that this findings exhibited a marked decrease compared to previous reports in
México, even with higher dosages of up to 1 mg/kg.
308
Giardial Cysteine-containing Proteins as Possible Targets of Thioallyl Compounds from Garlic. R.
ARGÜELLO-GARCÍA*, M. DE LA VEGA-ARNAUD, I.J. LOREDO-RODRÍGUEZ, A.M. MEJÍA-CORONA,
E. MELGAREJO-TREJO, E.A. ESPINOZA-CONTRERAS, Departamento de Genética y Biología Molecular, CINVESTAV-IPN, México DF, A. GONZÁLEZ-ROBLES, Departamento de Patología Experimental,
CINVESTAV-IPN, México DF, N. PÉREZ-HERNÁNDEZ, Facultad de Medicina, Universidad Autónoma
del Estado de Hidalgo, Pachuca, Hidalgo, and M.G. ORTEGA-PIERRES, Departamento de Genética y
Biología Molecular, CINVESTAV-IPN, México DF, México.
Fresh garlic extracts (FGE) and several thioallyl compounds from garlic (sulfides, thiosulfinates [allicin]
and cysteine derivatives) have an important antimicrobial activity that may be due to its interaction with
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ABSTRACTS
exposed sulphur/thiol groups in proteins. Giardia duodenalis trophozoites have a plethora of cysteine-rich
proteins including intracellular enzymes and cell surface proteins as potential targets for these compounds. We initially evaluated the mode of action of these compounds by in vitro susceptibility assays
using methods based on different criteria of cell viability (re-growth, membrane permeability, glycolytic/
diesterase enzyme activity). FGE impaired viability of trophozoites by a cytolytic mechanism that also
affected glycolytic and diesterase enzymes. Giardicidal activity of seven garlic’s thioallyl compounds
maintained a good relation with the molecular descriptor HOMO energy and also with their reactivity
on free cysteine or cysteine-containing proteins in trophozoite extracts. of all the thioallyl compounds
tested, allicin showed the highest antigiardial and cysteine-modifying activities. Allicin also displayed a
cytolytic mechanism on trophozoites but, interestingly, diesterases were affected before glycolytic enzymes. Electron microscopy studies showed a marked destruction of plasma membrane and endomembranes in allicin-treated trophozoites, but no effect was observed in cytoskeletal elements. When
gerbils were infected experimentally with G. duodenalis and given an intragastric administration of FGE
or allicin at single dose, low parasite numbers were recovered from infected animals. All together these
data give insights on sulfur-containing proteins and their metabolism as potential targets of thioallyl
compounds from garlic.
309
Differential Drug Metabolization and Expression of an Antioxidant Peroxiredoxin Between Albendazole-sensitive and Resistant Clones of Giardia duodenalis. R. ARGÜELLO-GARCÍA*, M. CRUZ-SOTO,
R. GONZÁLEZ-TREJO and M.G. ORTEGA-PIERRES, Departamento de Genética y Biología Molecular,
CINVESTAV-IPN, México DF, México.
Albendazole (ABZ) is a drug of common use for treatment of giardiasis, and drug resistance in Giardia
duodenalis is a problem of increasing concern. The molecular bases of resistance to ABZ in Giardia are
unknown. In some cellular models, it has been suggested that ABZ may cause a cytotoxic process of
oxidative stress. Giardia trophozoites are capable of metabolizing albendazole into albendazole sulfoxide
(ABZSO), which has significant anti-parasitic activity and further into albendazole sulphone (ABZSOO)
that exhibits lower activity. In our group, several albendazole-resistant cloned cultures have been obtained
by exposing the parasites to increasing sub-lethal drug concentrations (1.35, 5.6, 8 and 250 micromolar). Initially, using high-performance liquid chromatography, we tested the conversion of ABZ to
ABZSO/ABZSOO in ABZ-sensitive and resistant trophozoites after different times of exposure to ABZ.
Intracellular concentrations of ABZ were similar between sensitive and resistant cultures; however, the
levels of both ABZSO and ABZSOO were higher in sensitive cultures at different times of exposure to
ABZ (i.e., 24–48 hrs. and 6–48 hrs, respectively). Further studies of the proteome of ABZ-sensitive and
resistant cultures were performed by one and two-dimensional gel electrophoresis and some differential
bands/spots were identified by mass spectrometry. A peptide from an over-expressed spot corresponding
to giardial thioredoxin peroxidase was identified in the resistant cultures and confirmed based on the
correlation of its expected and observed MW/pI values (22.5 kDa/5.6). This enzyme, together with the
cysteine pool, may constitute a major antioxidant resource in Giardia. Taken together these data suggest
that a lower level of ABZ metabolization and over-expression of antioxidant enzymes may contribute to
the ABZ resistance in this parasite.
310
Analysis of the Cytotoxic Activity of Recombinant Scorpine on Bacteria, Malaria Parasites and Dengue
Virus. R. CARBALLAR LEJARAZU*, CISEI-INSP, Cuernavaca, Morelos, M.H. RODRÍGUEZ LÓPEZ, INSP,
Cuernavaca, Morelos, L.D. POSSANI POSTAY, Molecular Medicine Department, IBT-UNAM, Cuernavaca, Morelos, F.D. HERNÁNDEZ-HERNÁNDEZ, Experimental Pathology Department, CINVESTAVIPN, México DF, R. HERNÁNDEZ, Molecular Biomedicine, CINVESTAV-IPN, México DF, and H. LANZ
MENDOZA, CISEI-INSP, Cuernavaca, Morelos, México.
Transgenesis is a tool for insect transformation not only for making refractory mosquitoes, but also to
understand vector–parasite interactions. In recent years, important advances in the field of mosquito
vectors genetic manipulation have occurred, including the successful transformation of germinal lines,
yielding viable strains of transformed mosquitoes as well as the characterization of tissue-specific promoters for the expression of refractory genes. Nevertheless, identification of new molecules able to eliminate
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ABSTRACTS
invader microorganisms (effectors) is still necessary. It is desirable that toxic molecules cover a broad
spectrum of action that could block the transmission of diverse pathogens. Here, recombinant scorpine,
a peptide isolated from the venom of the scorpion Pandinus imperator was tested as a potential versatile
toxic molecule. Tha plasmid MinSEscp containing the full sequence of scorpine was constructed and
used to transfect Anopheles gambiae (Sua 5.1) and Aedes albopictus (C6/36) cells. The cytotoxic activity of
recombinant scorpine recovered from cell cultures was tested. Scorpine showed antibacterial activity
against Bacillus subtilis and Klebsiella pneumoniae at 5 µM and 10 µM, respectively. Scorpine was toxic to
sexual stages of Plasmodium berghei with 72% mortality of ookinetes and 98% mortality of gametes at 30
µM. It also was toxic to Plasmodium falciparum asexual stages with a 100% reduction in parasitemia at 40
h with a 5 µM concentration. Finally, we observed that scorpine inhibits virus dengue-2 assembly with
no production of NS3 virus protein, avoiding a C6/36 infection. These results show that scorpine could
be an effective toxic molecule against different pathogens and it may be used for refractory mosquito
generation by mean of transgenesis.
311
Ancient Migrations Based on Paleoparasitology. A. ARAUJO*, Escola Nacional de Saude Publica,
Fundação Oswaldo Cruz, Rio de Janeiro, Brasil, L.F. FERREIRA, de Publica, Fundação Oswaldo Cruz,
Rio de Janeiro, Brasil, A. IÑIGUEZ, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro,
Brasil, D. LELES, de Publica, Fundação Oswaldo Cruz, Rio de Janeiro, Brasil, and K.J. REINHARD,
University of Nebraska, Lincoln NE, USA.
Some human parasites were inherited from human ancestors and others acquired along human biological
and social evolution. Trichuris trichiura, Ascaris lumbricoides, Enterobius vermicularis and hookworms are
intestinal worms that infect humans. They are considered as heirloom parasites. Hookworm and whipworm eggs need special environmental conditions to complete their life cycles. A. lumbricoides eggs are
very resistant to soil variations. E. vermicularis is independent of environmental conditions to mature and
may infect human host directly. Infection dispersed out of Africa accompanying human hosts wherever
soil and climate conditions were favorable. Therefore, ancient migrants who crossed the cold region of
Beringia to people the Americas would have lost these parasites. However, hookworm and whipworm
eggs were found in human coprolites dating up to 7,230 years ago in South American archaeological
sites. Transpacific contacts or costal migrations were proposed to explain the introduction of these
parasites. Pinworm infection was recorded in archaeological sites all over the world. Recent molecular
biology studies found differences in strains recovered from South American archaeological sites, suggesting multiple migration origins for the parasite and its human host. A. lumbricoides infection was considered to be absent or rare during pre-Columbian times, but recently roundworm ancient DNA was
recovered from Amerindian coprolites. Paleoparasitological record shows that American indigenous
inhabitants were parasitized by the common intestinal parasites. Prevalence rates were low and seemed
never to have reached the high levels registered in mediaeval times in Europe. Therefore, it was only after
the coming of Europeans and Africans that intestinal parasites turned to be a public health problem, with
increasing prevalence rates.
312
Chagas Disease: From the Past to the Present. K. DITTMAR*, Department of Molecular Biology,
University of Wyoming, Laramie WY, K.J. REINHARD, School of Natural Resource Sciences, Lincoln
NE, USA, A. FERNANDEZ, A. ADAUTO, Instituto Oswaldo Cruz, ENSP, Rio de Janeiro, Brazil, M. FINK,
Arizona Department of Health Services, Phoenix AZ, USA and A. JANSEN, Instituto Oswaldo Cruz, Rio
de Janeiro, Brazil.
Chagas disease (American Trypanosomiasis) is still one of the most debilitating diseases in the Americas.
Every year the disease kills around 50,000 people, and roughly 25% of the population in the Americas is
at risk. The causative agent, Trypanosoma cruzi, a flagellate protozoan, is not a genetically uniform
parasite, and several subgroups have been identified. All of them have intricate and often poorly understood transmission cycles, involving various mammal hosts. Evolutionary age estimations of splits
between major T. cruzi groups, and its closest ancestor vary; however, it is clear that once humans
introduced themselves into the New World, they too became a target of Trypanosoma cruzi. Recent
archaeological, molecular and ecological evidence confirms this. This presentation will focus on findings
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from both the past (mummies) and the present in the Texas/Coahuila border region and in Brazil. We
will bring forward a comprehensive body of evidence based on molecular data, dating schemes, transmission cycles and life style of human hosts to elucidate the distribution of Trypanosoma cruzi in the Americas from prehistoric times until the present. Results from this research might be informative for future
studies, especially in the wake of upcoming climate changes.
313
Prehistoric Pathoecology of Ancestral Pueblo and Archaic Peoples. K.J. REINHARD, School of Natural
Resources, University of Nebraska Lincoln NE, USA.
Pathoecology is a term applied to the exploration of the effects of culture and environment on prehistoric
parasitism. More than 1,000 coprolites have been studied from the states of Utah, Arizona, New México
and Colorado. Dietary, environmental and parasitological data from these coprolites reveal how environmental collapse during times of drought resulted in an increase of intestinal parasitic disease. Comparative analysis of parasite prevalence in coprolites with village architecture shows that parasitism was more
common in large villages built in caves. The crowding of people in such villages resulted in contamination of the environment with helminth eggs. Certain parts of villages such as granaries, ceremonial rooms
and sleeping areas became nidi for endoparasites and ectoparasites. These details of parasite pathoecology
can be recovered from my multidisciplinary studies of coprolites in context with archaeological and
paleoenvironmental data. The emergence of human-specific and zoonotic parasitism has been documented in the nearly 10,000 years of time represented by coprolite studies. For nearly 8,000 years,
hunter–gatherers were infected with zoonotic parasites with occasional pinworm infections. Later, after
agriculture was established, human specific parasites emerged in Ancestral Pueblo peoples, possibly from
contact with advanced Mesoamerican cultures. The health impacts of parasitism and malnutrition can be
seen in skeletal symptoms of severe anemia that physical anthropologists have long identified in the
region. The variation of anemia ranges from 46% to 94% of infants. This can be related to the emergence of giardiasis, amoebiasis, and helminthiasis combined with declining nutrition in periods of
drought.
314
Helminth Parasites in Paleofeces from Cueva de los Muertos Chiquitos, Rio Zape Valley, Durango,
México. F.A. JIMÉNEZ*, The Harold W. Manter Laboratory of Parasitology, University of Nebraska State
Museum, Lincoln NE, and K.J. REINHARD, School of Natural Resources, University of Nebraska,
Lincoln NE, USA.
The analysis of coprolites (paleofeces) was originated with the study of samples from México. In the
1950s, the first dietary reconstruction of Mesoamerican societies was based on the analysis of coprolites
from the valley of Tehuacán. This reconstruction addressed more than 8,000 years of Mexican indigenous
cultural development. However, the study of parasites was not included in that research. Subsequently,
the techniques to perform parasitological analyses of coprolites were developed in Peru, Chile, Brazil and
the USA. We present the results of the parasitological study of coprolites from Cueva de los Muertos
Chuiquitos in the Rio Zape Valley, Durango This rocky valley has a series of caves that preserve corpolites. The coproltes revealed an interesting spectrum of helminth parasites at 600 AD, which signify a
contribution to the knowledge of helminth infections suffered by the people in the zone.
315
Where Rodent Pests and Reservoirs Meet: A Geographical Analysis of Agriculture Risk Areas for
Transmission of Chagas Disease in México. V. SÁNCHEZ-CORDERO*, Instituto de Biología, UNAM,
México DF, J. RAMSEY, Centro de Investigaciones sobre Enfermedades Infecciosas (CISEI), Instituto
Nacional de Salud Pública, Cuernavaca, Morelos, C. IBARRA, Instituto de Biología, UNAM, México DF,
México, and T. PETERSON, Natural History Museum, The University of Kansas, Lawrence KS, USA.
Rodents constitute agricultural pests as well as natural reservoirs for many diseases affecting humans
worldwide. In México, rodent pest species such as the cotton rat, Sigmodon hispidus, reach high densities,
imposing severe damage to widely distributed and economically important crops such as sugarcane, rice
and sorghum. Both rodents also are known to be reservoirs of Trypanosoma cruzi, the parasitic protozoan
responsible for Chagas disease, transmitted by blood-feeding insects of the Triatoma species group. It is
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estimated that Chagas disease affects two million people in México, being 57% resident of rural communities (Ramsey et al., 2003). We modeled the ecological niche of the species and then developed potential
geographical distributions, using a computer genetic algorithm (Garp, Genetic algorithm for rule-set
prediction; Stockwell and Peters, 1999) of both rodent pests (reservoirs), and species of the tratomine
Triatoma pallidipennis and Triatoma dimidiata (vectors), recognized as important vectors for transmitting
Chagas disease. Garp uses species’ point localities and environmental variables as input data to generate
the distributional predictions. We overlaid rodent and triatomine distributions to map agricultural areas
for potential transmission of Chagas disease. Rural communities living in these regions are likely to suffer
from both crop losses and high infection risk for Chagas disease. Our approach can serve to: (i) identify
potential host relationships for stratifying Chagas disease risk areas, and (ii) assist with planning of the
operational aspects of an integrated pest management program that will include a vector control program.
316
The Biomass of Parasites and the Energetics of Ecosystems. A.M. KURIS, Department of Ecology,
Evolution and Marine Biology, University of California, Santa Barbara CA, USA.
There is a physics of proportionality such that that effect (energy) should be proportional to mass. Many
empirical studies indicate that infectious agents often have great impacts at all levels—host individuals,
populations and communities. Yet infectious agents are perceived as having negligible mass. To resolve
this paradox, we quantified the weight-specific abundance of the free-living organisms in three salt
marshes along the coast of California and Baja California. For all potential hosts, we also estimated the
biomass of all infectious agents amenable to detection, and the daily productivity (cercariae) of the most
substantial infectious component (trematode parthenitae) in these ecosystems. (1) Larval trematode
biomass exceeded the biomass of the avian predators; (2) cercarial productivity averaged more than one
trillion/day; and (3) parasitic castrators exceeded the standing crop of other types of infectious agents.
Considerable energy flows through the infectious process. Finally, I consider the relevance of this evaluation to other ecosystems and to human infectious diseases.
317
Spatial Analysis of Boophilus microplus Resistance to Acaricides in Southeastern México. A.L. RIVAS*
and R.I. RODRÍGUEZ-VIVAS, College of Veterinary Medicine, UADY, Mérida, Yucatán, México.
The resistance (or susceptibility) displayed by Boophilus microplus strains to several acaricides (amidines or
Am, synthetic pyrethroids or SP, and organo-phosphates or OP) was investigated in 217 southeastern
Mexican cattle ranches located in the states of Yucatán, Quintana Roo, and Tabasco. Three questions
were asked: (1) whether acaricide profiles varied at random and, if not, which one(s) explained more (or
less) cases than expected; (2) whether the spatial distribution of acaricide profiles is randomly or nonrandomly distributed; and (3) whether acaricide profiles may be associated with farm-related covariates
(frequency of annual treatments, herd size, and farm size). Three acaricide profiles explained 73.6 % of
the data, representing at least twice as many cases as expected (P less than 0.001): (1) Am– SP–, 2)
Am+ SP+, and (3) (among ranches that dispensed acaricides 6 or more times/year) Am– OP+ SP+.
Because ticks collected in Yucatán ranches tended to be susceptible to Am, those of Quintana Roo
ranches displayed, predominantly, resistance to OP/SP, and Tabasco ticks tended to be resistant to Am (all
with P less than 0.05), acaricide profiles appeared to be non-randomly disseminated over space. Across
states, two farm-related covariates were associated with resistance (P less than 0.02): (1) high annual
frequency of acaricide treatments, and (2) large farm size. Findings supported the hypothesis that spatial
acaricide profiles followed neither random nor homogeneous data distributions, being partially explained
by agent- and/or farm-specific factors.
318
The Alien Helminth Parasites of Mexican Freshwater Fish. G. SALGADO-MALDONADO*, UNAM,
México, and T. SCHOLZ, Academia de Ciencias de la República Checa.
A total of 19 alien helminth species have been introduced into Mexican freshwater fish. They are distributed in 13 genera and six families from two taxonomic groups: Platyhelminthes (three trematodes, 13
monogeneans, and two cestodes); and Nematoda (one species). Alien helminths have been introduced
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through the importation and captive production of Asian carps, African tilapias and North American
bass during the 20th century and mostly within the last 50 years. Introduction of fish species is responsible for the presence of most alien helminth species in México, although two were introduced with their
first intermediate host, the snail Melanoides tuberculata. The current geographical distribution of these
alien species can be explained by the management methods used for freshwater fish established in
México. Each hydrological basin or state analyzed has only a few alien helminth species. Most of the alien
species have been recorded in Tabasco, the Yucatán Peninsula and the Río Lerma basin, and are present
in just one basin or state, though Centrocestus formosanus and Bothriocephalus acheilognathi have the widest
spatial distribution and presence in the most host species. Almost all of the alien monogenean species
have been recorded in ponds and some natural bodies of water in Tabasco and the Yucatán Peninsula, and
are mainly associated with the presence of African tilapias. Alien helminth infection is frequently quite
acute in the neotropical freshwater fish families Cichlidae and Poeciliidae and is especially marked in the
endemic Atherinidae and Goodeidae families. Anthropogenic activity has been a more important factor
than the biological characteristics of alien helminth species, aiding in their successful introduction and
establishment.
319
Coccidiosis Vaccination in Combination with the Use of an Ionophore in the Grower Feed Improved
Performance When Compared to a Traditional Coccidiosis Vaccination Program. M. QUIROZ*, J.
DIBNER, C. KNIGHT, Novus International Inc., St. Louis MO, USA, B. SÁNCHEZ, Novus International
de México, México, and T. CHERRY, Stephen F. Austin State University, Nacogdoches TX, USA.
Field experience indicates that broiler performance and skin pigmentation may improve when using a
combination of a coccidiosis vaccine followed by a coccidiostat in the grower feed. Traditionally, coccidiosis control programs include either a vaccination program or the use of anticoccidials in the feed. Today,
several broiler companies in México are using a “Bioshuttle program” that consists of the use of a
coccidiosis vaccine at one day of age, followed by anticoccidials in the feed after 10 days of age, with a
variable withdrawal period. The purpose of the present study was to compare commercial performance
parameters of two Coccidiosis Vaccine control programs: ADVENT® Coccidiosis vaccine, and ADVENT Coccidiosis vaccine with a low level of Monensin in the grower feed. (All birds received BMD-60
and 3-Nitro.) ADVENT contains sporulated viable oocysts from the three commercially relevant species
in broilers, E. acervulina (strain VND-A10), E. maxima (strain VND-M27), and E. tenella (strain VNDT49). Screening for anticoccidial drugs resistance confirmed the sensitivity of the strains to ionophores
and chemical drugs. The study compared performance parameters on a commercial broiler farm. The
placement of birds was in four tunnel-ventilated, commercial broiler houses. Houses 1 & 2 (Farm 1)
were the ADVENT Coccidiosis Vaccine with low level of Monensin in the grower feed (from day 18 to
day 35), and houses 3 & 4 (Farm 2) were the ADVENT Coccidiosis Vaccine treatments. Farm 1 resulted
in seven points better adjusted feed conversion vs. Farm 2. Farm 1 also exhibited 16 points adjusted feed
conversion advantage over the complex average, which was on a regular anticoccidial shuttle program
(Nicarbazin + Monensin). Farm 1 birds weighed 77 grams greater than those on Farm 2, and 218 grams
more than the balance of the complex. These data provide evidence that a Bioshuttle program combining
a live coccidia vaccine followed by anticoccidials in the feed may improve broiler performance when
compare to the use of traditional coccidiosis control programs with either vaccine or anticoccidials in the
feed.
320
The Gel Spray Delivery of Coccidiosis Vaccine. E.H. LEE*, A. SUNNUCKS, S. ANDRESS and T.
COSSTICK, Vetech Laboratories Inc., Guelph, Ontario, Canada.
For the last two decades, uniform exposure (Lee, 1986) has been accepted generally as the basis for
successful delivery of live coccidiosis vaccines to commercial poultry. The delivery method to achieve
uniform exposure now is generally by water spray. Although we were the first to try water spray more
than 10 years ago (Danforth et al, 1997), we felt that the gel spray method could overcome some of the
shortcomings of water spray. Water cannot suspend the oocysts, thus explaining why a constant stirring
of the vaccine is needed before water spray delivery. The suspension of coccidial oocysts in the gel spray
delivery, once mixed, will last for hours without further agitation. As shown here, the droplets of water
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spray average only one tenth to one fifteenth the volume of those of gel spray, both delivered under the
same conditions. Gel droplets can sustain oocyst uniformly for several hours, even though the actual time
for the consumption of gel droplets by the birds is only two to three minutes. Because of this, the gel
spray method can be delivered either by a hand-held sprayer or an automated sprayer with a specially
designed header through the conveyor belt. More than 90% was the usual take, demonstrated by the
colored beaks and tongues of the hatchlings inspected 10 to 15 minutes after vaccination. Commercial
results so far appear to show that this method performed as well as our water diluent or gel puck
method. Both methods have been shown (Dasgupta and Lee, 2000) to provide uniform exposure to
vaccinated hatchlings. Features that distinguish gel spray from water spray are the gel spray system
provides assured uniform exposure; sustained suspension of oocyst vaccine mixtures in droplets; and with
droplets of a visible size that stick to the feathers, easy pick-up by the hatchlings.
321
Coccivac–Eimeria maxima Protected Against Field Isolates. S.H. FITZ-COY, Schering-Plough AH,
Summit NJ, USA.
In a series of tests, the antigenicity of recent field isolates of E. maxima were compared against that in
Coccivac. Field isolates were collected from 80 broiler and breeder pullet farms across the USA. The
chickens were inoculated per os with one dose of Coccivac-B or Coccivac-D during the first week of life.
Inoculated birds were placed into floor pens on clean wood shaving, then grown to approximately 30
days of age. Following immunization, the birds were tagged and placed into assigned treatment groups.
Attempts were not made to purify the inocula, but the E. maxima levels were standardized at 100,000
sporulated oocysts per bird. Birds from the immunized group and their un-immunized hatch-mates were
challenged with inocula of field isolates. The un-immunized hatch-mates served as the positive controls.
The challenge phase lasted between 144 to 156 hr, followed by euthanasia and necropsy, with intestines
examined grossly for coccidial lesions using a 0 to 4 scoring system. Mucosal scrapings taken from the
duodenal loop, jejunum and ileum then were placed on microscope slides for microscopic evaluations.
Microscopic evaluations (scored 0 to 4) were taken using a compound light microscope. Severity of
infection (0 = no parasite, 1 = 1 to 10 per field, 2 = 11 to 20 per field, 3 = 21 to 40 per field, and 4 ≥
50 per field for E. maxima). Birds immunized with Coccivac and challenged with field isolates demonstrated substantial immunity, as determined by the level of parasitisms in the immunized birds vs. the
non-immunized groups. Data showed the E. maxima antigen in Coccivac provided good protection
against field isolates.
322
Biologic and Molecular Tools in the Use of Live Oocyst Vaccines. M.C. JENKINS* and K.B. MISKA,
APDL, ARS, USDA, Beltsville MD, USA.
With the increasing use of live oocyst vaccines to control avian coccidiosis, there is a need for sensitive
methods to estimate the relative prevalence of Eimeria species in poultry operations. These methods
should provide data on the relative numbers of different Eimeria oocysts in litter, and be able to distinguish field strains from vaccine strains of the parasite. A technique was developed that rapidly isolates
Eimeria oocysts directly from litter. The oocysts are then extracted for DNA, which is then subjected to
species-specific polymerase chain reaction (PCR). The utility of this technique recently was shown by a
comparison of Eimeria oocysts populations in litter from high-performance and low-performance poultry
farms in three different U.S. broiler regions. All operations used a combination of drug treatment and
vaccination to control coccidiosis. Although oocyst concentrations in litter were similar between all
poultry operations, higher numbers of E. maxima often were associated with low-performance farms.
Also, E. acervulina and E. praecox often were found at high concentrations irrespective of broiler operation type. E. praecox oocysts were isolated, and pathogenicity studies were conducted on this infrequently
identified Eimeria species.
323
Iron Regulation in Trichomonas vaginalis. R. ARROYO*, C.D. LEÓN-SICAIROS, Departamento de
Patología Experimental, CINVESTAV-IPN, México DF, E. SOLANO-GONZÁLEZ, Departamento de
Biotecnología y Bioingeniería, CINVESTAV-IPN, México DF, J.C. TORRES-ROMERO, Departamento de
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ABSTRACTS
Patología Experimental, CINVESTAV-IPN, México DF, and J. ORTEGA-LÓPEZ, Departamento de
Biotecnología y Bioingeniería, CINVESTAV-IPN, México DF, México.
Iron is an essential nutrient for the growth, metabolism and expression of virulence factors for many
pathogens, including Trichomonas vaginalis. In trichomonads, iron modulates the differential expression
of surface antigens, hydrogenosomal proteins, and virulence factors, affecting the parasite virulence. For
example, iron up-regulates parasite resistance to complement lysis, the levels of cytoadherence, and
relocalization of the trichomonad adhesins. Iron down-regulates the levels of cytotoxicity by negatively
affecting the gene expression of CP65, one of the CPs involved in cellular damage. Transcription of some
virulence genes and others also is modulated by iron; i.e., four of the five reported adhesins and the
tvlegu-1 genes are transcribed in the presence of iron, whereas the p270, flp-1, flp-2, tvcp65 and tvcp12
genes are transcribed in its absence. All these data show that iron could have a dual effect in T. vaginalis
gene expression, suggesting a very fine-tuned mechanism of iron regulation at transcriptional and
posttranscriptional levels. The transcriptional iron regulation is mediated by an iron regulatory promoter
element found at the 5r untranslated region (UTR) of the positively-regulated ap65 gene, and by MYBlike proteins. The post-transcriptional regulation is mediated by an IRE/IRP-like system. It involves
stem-loop iron regulatory elements (IRE) found at the 5r or 3r UTR’s of target mRNAs, and iron
regulatory proteins (IRP-1/IRP-2-like proteins) that specifically bind to the hairpin structures at low iron
concentrations. Depending of the IRE location, these interactions will block protein synthesis or stabilize
the mRNA. Examples of this type of iron regulation are observed in the positively-regulated tvcp4
mRNA, which has an IRE-like hairpin at its 5r end; and in the negatively-regulated tvcp12 mRNA,
which shows an IRE-like structure at its 3rUTR. Both IRE-like RNA structures bind the human IRP-1
and trichomonad IRP-like proteins, suggesting that an IRE/IRP-like mechanism of iron regulation is
present also in this ancient parasite.
324
Field Research on Intestinal Parasites in Malnourished Children—Is this Type of Project for You? M.E.
SCOTT, Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada.
Many graduate students are excited about the possibility of doing research that “makes a difference,” and
are thus drawn to opportunities to study parasitic infections in human communities in developing
countries. Using examples where Canadian graduate students have conducted research involving Mexican
and Panamanian children, I will review the challenges associated with such research, highlight the
personality traits and experience that allow students to succeed, and give examples of some of the
insights that can emerge from such research.
325
New Tools for the Control of Chagas Disease and Leishmaniasis. E. DUMONTEIL, Laboratorio de
Parasitología, CIR, Universidad Autónoma de Yucatán, Mérida, Yucatán, México.
Leishmania sp. and Trypanosoma cruzi are protozoan parasites responsible for leishmaniasis and Chagas
diserase, respectively. Both diseases remain important public health problems, in part due to limited
control tools. Thus, we have been investigating new alternatives for the control of these diseases. Studies
of the biology and ecology of Chagas disease vector Triatoma dimidiata, using a combination of theoretical, field and laboratory approaches, led us to design new vector control strategies that are now been
implemented with Health Authorities for their validation. On the other hand, we have been developping
prophylactic and therapeutic vaccines against both parasites. Extensive studies in mouse models have
allowed us to identify promising DNA vaccine candidates that are now being evaluated in advanced preclinical trials in hamsters, dogs and monkeys. These studies will provide the basis for the development of
veterinary vaccines and future clinical trials in humans. We also are using funtional genomics to identify
new vaccine candidates from the genome sequence of these parasites, and an initial screening of Leishmania major genome allowed the identification of 11 new vaccine candidates. Taken together, these approaches should lead to the development of novel control alternatives for these neglected diseases.
326
Effects of Selective Logging and Forest Fragmentation On Primate–Parasite Interactions. T.R.
GILLESPIE*, Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana
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IL, E.C. GREINER, College of Veterinary Medicine, University of Florida, Gainesville FL, USA, and C.A.
CHAPMAN, Department of Anthropology, McGill University, Montreal, Canada.
There is a growing recognition of the importance of land-use change and human–wildlife linkages in
disease emergence and ecosystem health. Recently, we completed a series of investigations demonstrating
that certain disturbance-related features of degraded forests are excellent predictors of infection rates in
primates and of the prevalence of parasites shared among primates, people and livestock in and around
Kibale National Park in Uganda. In this five-year study, we compared patterns of gastrointestinal parasite
infection and infection risk among metapopulations of multiple monkey species inhabiting undisturbed
forest, selectively logged forest, and a series of forest fragments. Our results demonstrated that forest
fragmentation and selective logging increased parasite prevalence and infection risk, and that certain
attributes of forest fragments were strongly associated with infection patterns. These results suggest that
the degree and nature of anthropogenic disturbance to forests significantly affect the dynamics of infection by gastrointestinal parasites.
327
Can the Common Brain Parasite, Toxoplasma gondii, Influence Human Culture? K.D. LAFFERTY,
Western Ecological Research Center, USGS, Marine Science Institute, University of California, Santa
Barbara CA, USA.
The latent prevalence of a long-lived and common brain parasite, Toxoplasma gondii, explains a statistically
significant portion of the variance in aggregate neuroticism among populations, as well as in the “neurotic” cultural dimensions of sex roles and uncertainty avoidance. Spurious or non-causal correlations
between aggregate personality and aspects of climate and culture that influence T. gondii transmission
could also drive these patterns. A link between culture and T. gondii hypothetically results from a behavioural manipulation the parasite uses to increase its transmission to the next host in the life cycle, a cat.
While latent toxoplasmosis is usually benign, the parasite’s subtle effect on individual personality appears
to alter aggregate personality at the population level. Drivers of the geographic variation in the prevalence of this parasite include the effects of climate on the persistence of infectious stages in soil, and the
cultural practices of food preparation and cats as pets. Some variation in culture, therefore, may ultimately be related to how climate affects the distribution of T. gondii, though the results only explain a
fraction of the variation in two of the four cultural dimensions, suggesting that if T. gondii does influence
human culture, it is only one of many factors.
328
The Role of Sex Steroids in the Host–Parasite Neuroimmunoendocrine Network: Consequences to the
Host and the Parasite. J. MORALES-MONTOR, Departamento de Inmunología, Instituto de Investigaciones Biomédicas de la UNAM, México DF, México.
We discuss here the role that sex steroids play in experimental intraperitoneal Taenia crassiceps cysticercosis of male and female BalbC/AnN mice. Briefly, estrogens favor and androgens hinder the reproduction
of cysticerci by at least two main mechanisms: (1) through estradiol tilting the TH2/TH1 immune
system balance towards parasite-permissive TH2 responses, accomplished by way of TH2 dependent IL6 mediating P450-aromatase over expression, shunting testosterone towards estradiol and thus creating a
positive feed-back loop that progressively favors TH2, blocks TH1 responses and furthers parasite
growth; and (2) in vitro estrogens and androgens act directly upon the cysticercus reproductive system,
favoring or hindering, respectively, its asexual reproduction. Late in infection, when parasite loads are
immense, male mice become estrogenized, deandrogenized and diminish their copulative, aggressive and
social behaviors in association with P450-aromatase overexpression. Changes in c-fos and progesterone
receptor expression in different areas of the brain of the infected mice point to the additional connection
of the brain with the infection-driven events, which senses and perhaps reacts to infection with behavioral changes. This complex immuno-neuro-endocrine network management of parasite loads in murine
cysticercosis, and its physiological and behavioral consequences upon the host, may be operative in other
infections of mammals. Such complexity also may help to explain the often conflicting results observed
between infections with respect to the role of the hosts sex, and hints to other avenues of research and
strategies for their treatment and control.
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329
A Galectin from Hemocytes of the Oyster (Crassostrea virginica) Is a Potential Receptor for the Parasite
Perkinsus marinus. G.R. VASTA* and S. TASUMI, Center of Marine Biotechnology, University of
Maryland Biotechnology Institute, Rockville MD, USA.
Although the Eastern oyster (Crassostrea virginica) is endowed of efficient innate immune recognition
and effector mechanisms that are successful in fighting most potentially pathogenic microbes, they
become readily infected when exposed to Perkinsus marinus, a protozoan parasite responsible for mass
mortalities in native and farmed oyster populations in the Atlantic and Gulf coasts of the U.S.A. We have
cloned and characterized the cDNA and the gene organization of a galectin of unique domain organization present on the surface of the oyster hemocytes that may function as a receptor for the protistan
parasite P. marinus. The 1668 nucleotides-long transcript, encoding 555 amino acid residues (CvGal),
revealed the presence of four galectin-like carbohydrate recognition domains (CRDs). The CvGal gene is
composed of 12 exons divided by 11 introns, none of which are present within the regions encoding each
CRD. CvGal is mostly expressed in hemocytes, and its binding activity is strongly inhibited by lactose,
N-acetyllactosamine and thiodigalactose, and several glycoproteins, including lactoferrin, laminin,
thyroglobulin, and asialofetuin. Comparative binding studies that included bacteria, algae and the
Perkinsus spp. revealed that CvGal binds very efficiently to the surface of Perkinsus spp trophozoites, and
that the binding is carbohydrate-mediated, This evidence, together with the observation that P. marinus
efficiently abrogates the respiratory burst elicited upon phagocytosis, suggests that this recognition
system may have been possibly subverted as an infectivity mechanism by the parasite P. marinus. (Supported by NIH Grant R01 GM070589-01 and NSF Grant MCB-00-77928.)
330
Development of Cryptosporidium parvum in Avian Embryos. K.M. WOODS, C. NORRIS and S.J.
UPTON*, Division of Biology, Kansas State University, Manhattan KS, USA.
We examined development of calf-derived Cryptosporidium parvum (KSU-1 isolate) in White leghorn eggs
at 37°C and attempted to optimize several parameters in order to gain maximum oocyst production. Age
of embryos at time of inoculation, number of inoculations per embryo, and age of embryos at harvesting
were all factors taken into consideration. Studies revealed variability between embryos to be quite high,
similar to mammalian in vivo models. Preliminary results, however, revealed 11 day old embryos, harvested seven days later, yielded the highest number of oocysts per egg. Oocysts were found both in the
CAM and urates. Three inoculations per egg was somewhat superior to one inculation per egg in
successfully establishing infections. The optimal number of viable oocysts inoculated per egg was 10,000,
and oocyst yields tended to vary per batch of eggs and batch of oocysts. Oocysts harvested from eggs
were infective to new batches of eggs at levels similar to calf-derived oocysts. Several techniques were
developed or modified to simplify and streamline the process, and drawbacks to the technique will be
discussed. (Supported by NIH grant R21 AI052730.)
331
Characterization of Plasmodium falciparum Erythrocyte-binding Ligand EBL-1. G.D. MAYER*, L.
MENDOZA, Department of Biology, Virginia Commonwealth University, Richmond VA, and L.H.
MILLER, Laboratory of Malaria and Vector Research, National Instiyutes of Health, Bethesda MD, USA.
The malarial parasite lives within erythrocytes and depends on the binding of parasite ligands to erythrocyte surface receptors for invasion. Plasmodium falciparum uses multiple ligands of the Duffy binding-like
family of erythrocyte-binding proteins (DBL-EBP) for binding to human erythrocytes. Each ligand of
the DBL-EBP family recognizes and binds to a distinct erythrocyte receptor. This family is composed of
five members, all of which have been characterized except for Erythrocyte Binding ligand 1, EBL-1. Like
other members of the DBL-EPB family, it is expressed late in schizogony. We have studied EBL-1 to
determine its localization, its erythrocyte receptor specificity, and its possible role in invasion. By confocal
immunofluorescence microscopy, we find that, in contrast to the other members of the DBL-EBP family,
EBL-1 localizes to the rhoptries. Region II, the erythrocyte-binding domain of the DBL-EBP family, was
expressed on the surface of CHO-K1 cells and found to bind to human erythrocytes. We tested its
binding to trypsin-, chymotrypsin- and neuraminidase-treated human erythrocytes. We found that EBL-1
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bound to trypsin-treated, but not to chymotrypsin or neuraminidase-treated human erythrocytes,
suggesting that the erythrocyte receptor for EBL-1 is a sialoglycoprotein. We tested the binding of EBL1 to genetically mutant human erythrocytes lacking glycophorin B, a trypsin-resistant sialoglycoprotein,
and found that EBL-1 bound these cells, indicating that glycophorin B alone was not the receptor. P.
vivax has disappeared from West Africa because it relies solely on the Duffy blood group antigen. On the
other hand, P. falciparum may have persisted in all endemic areas because EBL-1, one the ligands of the
Duffy binding-like family, creates redundancy in the invasion pathways. These ligands also may be
responsible for P. falciparum’s ability to invade all aged human erythrocytes.
332
Neuron Specific Enolase (NSE) and S-100b Protein in the Serum of Toxoplasma gondii Congenitally
Infected Children. J. HERNÁNDEZ-ISLAS*, Instituto Nacional de Pediatría, SSA, M. GALVÁNRAMÍREZ, Universidad de Guadalajara, D.N. SOLÍS-RIOS, I. CAÑEDO-SOLARES, H. LUNA-PASTÉN,
E. CALDERÓN-SEGURA, M. VELA-AMIEVA, M. PÉREZ-ANDRADE, P. GUTIÉRREZ-CALDERÓN and D.
CORREA, Instituto Nacional de Pediatría, SSA, México.
Most newborns with Toxoplasma gondii congenital infection are subclinical at birth, but may develop
sequels later in life, in some cases in spite of drug therapy. Destruction of cells and tissues before they
cause clinical problems could partially explain this phenomenon. The neuron specific enolase (NSE) and
S-100b protein (specific of astrocytes) have been used to predict clinical outcome in stroke, cranial
trauma and open heart operated persons after resuscitation. By means of monoclonal-based antigen
capture ELISAs, in this study we quantified the levels of NSE and S-100b in the serum samples of
newborns and infants with symptomatic and subclinical congenital toxoplasmosis, as well as in noninfected control babies born by women with and without chronic infection. We separately analyzed those
samples positive for IgM and/or IgA anti-T. gondii antibodies from those presenting IgG only (i.e.,
“chronic”). The levels of both proteins were significantly higher in newborns with subclinical infection
and IgM/IGA antibodies, as compared to the rest of the groups. Although these results are preliminary,
they suggest that, like for other non-infectious disorders, NSE and S-100b are elevated in cases with
tissue damage caused by T. gondii, yet are subclinical and thus these molecules could have a potential
importance in prognosis. (This work was partially supported by Grant U-43079-M from CONACYT,
México.)
333
Trypanosoma cruzi in Mesomammals from Arizona and Georgia. M.J. YABSLEY*, E.L. BROWN, Warnell
School of Forestry and Natural Resources and the Southeastern Cooperative Wildlife Disease Study,
College of Veterinary Medicine, The University of Georgia, Athens GA, K.M. WENNING, Animal Plant
Health Inspection Service, Wildlife Services, USDA, Phoeniz AZ, and D.M. ROELLIG, Department of
Infectious Diseases and the Southeastern Cooperative Wildlife Disease Study, College of Veterinary
Medicine, The University of Georgia, Athens GA, USA.
Trypanosoma cruzi, the causative agent of American trypanosomiasis (Chagas disease), is a substantial
public health problem in Latin America. In the U.S., wildlife are the primary hosts, although some
domestic animal and human cases have been reported. A wide range of mammals are naturally infected
with T. cruzi, but little is known about which species serve as primary reservoirs from different geographic regions of the U.S. Serum samples from 109 mesomammals from two ecologically distinct states
in the U.S. (Georgia and Arizona) were tested for anti-T. cruzi antibodies using the indirect immunoflourescent antibody test. In Georgia, 14 of 40 (35%) raccoons and 10 of 26 (38%) opossums were
seropositive for T. cruzi at a 1:40 titer cutoff. The similar prevalence in raccoons and opossums from
Georgia suggests that the exposure level of raccoons and opossums is similar. However, these data are in
contrast to previous studies based on culture, which indicated that the T. cruzi prevalence was lower in
opossums compared with raccoons. This is the first study to investigate the seroprevalence of T. cruzi in
Virginia opossums. In northern Arizona, all tested striped skunks (n = 36) and raccoons (n = 4) were
seronegative. From southern Arizona, serum samples were available from three mammals (one each from
a ringtail, striped skunk, and raccoon); all three were seropositive. These data suggest that transmission is
less common in northern Arizona compared with southern Arizona. Once complete, this study will bring
insight into the seroprevance in these and additional hosts from multiple states in the U.S, potential
200
ABSTRACTS
temporal changes in seroprevalence, and differences in seroprevalence between urban and rural mammal
populations.
334
Modeling of a Potentially Unique Sylvatic Cycle For Trypanosoma cruzi in the Southeastern United
States. C.A. HALL*, Department of Biology, Berry College, Rome GA, C. KRIBS-ZALETA, Department
of Mathematics, University of Texas, Arlington TX, E.M. PIERCE, A.N. WIMSATT, J.B. MEERS and K.
NEWCOMB, Department of Biology, Berry College, Rome GA, USA.
Although Trypanosoma cruzi is found commonly in sylvatic reservoir species throughout the southeastern
United States, the incidence of autochthonous transmission to humans is rare. Surveys of sylvatic
reservoirs have demonstrated a correlation between host species and the T. cruzi strain, with opossums
(Didelphis virginiana) predictably infected with Type I strains, and raccoons (Procyon lotor) ) with Type
IIa. Despite similar environmental niches and behavior, the prevalence of T. cruzi is frequently higher in
raccoon populations than in opossums from the same area. To test whether vertical transmission may
play a role in this dichotomy, we tested experimentally the ability of different T. cruzi strains to be
transferred from mother to offspring at different rates. In outbred mice, a regional Type IIa isolate was
transferred to 66% of progeny born to infected females, as opposed to 33% of those infected with a Type
I strain. Consistent with theories of virulence management, the Type IIa strain has proven to be of low
pathogenicity, manifesting lower overall replication rates in vitro and in vivo. Infection and challenge
experiments showed that the Type IIa strain also imparted significant protection against a challenge with
a more virulent Type I strain. Further support for the likely importance of vertical transmission was
found in vector surveys of areas supporting high T. cruzi prevalence in reservoir populations. An extensive survey and trapping effort for Triatoma sanguisuga in a peri-domestic site with a 70% prevalence of
infection in the raccoon population failed to provide any evidence of vector presence. We have developed
a novel epidemiological model designed to address the relative contributions of vertical and horizontal
transmission in this potentially unique endemic system.
335
First Report of Autochthonous Transmission of the Chagas Parasite, Trypanosoma cruzi, in Louisiana and
Sixth in United States. P.L. DORN*, L. PERNICIARO II, Department of Biological Sciences, Loyola
University New Orleans, New Orleans LA, M.J. YABSLEY, D.M. ROELLIG, Department of Population
Health, College of Veterinary Medicine, University of Georgia, Athens GA, G. BALSAMO, Louisiana
Office of Public Health, Metairie LA, J. DIAZ, Louisiana State University Health Sciences Center, New
Orleans LA, and D. WESSON, Department of Public Health and Tropical Medicine, Tulane University
Health Sciences Center, New Orleans LA, USA.
An astute pest-control operator identified kissing bugs (Family Reduviidae, Subfamily Triatominae)
while treating a house following numerous bites suffered by one resident. The residents realized the risk
for Chagas disease and contacted a local health sciences center. We investigated and found many triatomines and identified them as Triatoma sanguisuga using the key of Lent and Wygodzinsky. One of the
two residents tested positive by immunofluorescent antibody test and an experimental dipstick assay
(InBios, International) and negative by PCR. T. cruzi parasites were obtained by co-culture with canine
macrophages from her blood (confirmed by amplification of Trypanosoma cruzi-specific 24Sα-rRNA
gene). Fifty-seven percent (21/34 bugs that successfully amplified) of T. sanguisuga collected were
positive for T. cruzi by PCR. The infected resident has a very limited travel history to endemic areas, no
other risk factors and has lived in this rural house, surrounded by woods, with many access points for
insects for 29 years. Therefore, it is quite likely the resident acquired the parasite in rural New Orleans.
Although occasional triatomines had been found previously in the house, a large influx was noted
following hurricane Katrina. This is the sixth case of autochthonous transmission of the Chagas parasite
in the United States and first described in Louisiana.
336
Seroprevalence of Antibodies Against Trypanosoma cruzi in Pregnant Women in México. R. GAMBOALEÓN*, Laboratorio de Parasitología, CIR, Universidad Autónoma de Yucatán, Mérida, Yucatán, N.
PADILLA-RAYGOZA, Facultad de Enfermería y Obstetricia de Celaya, México.O. ALMENDARES, M.
201
ABSTRACTS
CAFFERATA, M. JAMES, School of Public Health and Tropical Medicine, Tulane University, New
Orleans LA, USA, E. DUMONTEIL, Laboratorio de Parasitología, CIR, Universidad Autónoma de
Yucatán, Mérida, Yucatán, México, and P. BUEKENS, School of Public Health and Tropical Medicine,
Tulane University, New Orleans LA, USA.
Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and is the most important cause of
heart disease in Latin America. Endemic countries should consider congenital T. cruzi infection as a
public health problem, but in México, only a single case has been reported. The objectives of this study
were (1) to determine the seroprevalence of anti-T. cruzi antibodies in pregnant women, (2) to validate
the use of a rapid immunochromatographic test compared to a commercial ELISA test, and (3) to
validate the detection of T. cruzi-specific antibodies in cord blood samples versus maternal blood. Venous
blood was collected from a total of 1,000 pregnant women at the time of delivery, as well as matched
cord blood samples, in the Hospital Materno Infantil, Mérida, Yucatán, and the Hospital General de
Celaya, Guanajuato. Anti-T. cruzi antibodies were detected using Chagas Stat-PakTM (Chembio Diagnostic Systems Inc., New York NY) rapid test and a recombinant ELISA test (Ver. 3.0, Wiener Lab,
Argentina). Stat-PakTM tests indicated a seroprevalence in pregnant women of 0.8%, with a concordance
of 498/500 between venous and cord blood samples. Stat-PakTM diagnostic from 180/180 venous blood
samples were confirmed by ELISA, and from 179/180 cord blood samples. These preliminary results
seem to validate the use of Stat-PakTM rapid test in pregnant women as well as the use of cord blood
samples for the study of congential Chagas disease.
337
Interrelationships and Host Associations of the Onchobothriid Cestodes of Carcharhiniform Sharks. J.N.
CAIRA*, Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs CT, K.
JENSEN, Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence KS, USA, A.
WAESCHENBACH and T.J. LITTLEWOOD, Department of Zoology, The Natural History Museum,
London, England.
The onchobothriid cestode genera that parasitize carcharhiniform sharks generally exhibit strict specificity at the family level. The monotypic Erudituncus, three species of Biloculuncus, and 12 species of
Calliobothrium are restricted to the Triakidae (Houndsharks), the two species of Megalonchos to the
Hemigaleidae (Weasel sharks), and the 26 species of Phoreiobothrium and 18 species of Platybothrium
parasitize the Carcharhinidae (Requiem sharks) and Sphyrnidae (Hammerhead sharks). The monophyly
of these cestode genera, their interrelationships, and the degree to which their phylogenetic relationships
reflect host phylogeny were addressed by sequencing ~1200 bp of nuclear 28S rDNA for ~40 species
representing all but the first two genera. Phylogenetic analyses support the monophyly of each genus.
The results further support two distinct clades of Phoreiobothrium, one parasitizing the Sphyrnidae and
one the Carcharhinidae. Less well supported was the existence of two such clades in Platybothrium. The
existence of two distinct groups of Callibothrium, one comprised of small, non-laciniate species, and one
of large, laciniate species, was confirmed. It is interesting that, whereas most species of carcharhinid and
sphyrnid sharks are parasitized by species of Phoreibothrium and one species of Platybothrium, each
species of triakid shark is parasitized by representatives from each of the two Calliobothrium clades. The
relationships among these four genera were found to be fairly stable relative to one another in these
restricted analyses; Phoreiobothrium and Platybothrium generally grouped as sister taxa, followed by
Megalonchos, with Calliobothrium hypothesized to be the earliest divergent lineage. These relationships
are consistent with the current notion that carcharhinid and sphyrnid sharks are each others’ closest
relatives, but they are inconsistent with the hypothesis that hemigaleid sharks diverged earlier than
triakid sharks. In broader analyses, however, that include non-hooked taxa, these onchobothriid genera
are not necessarily monophyletic with respect to one another.
338
Morphological and Molecular Evidence for Patterns of Diversity and Host Specificity of Rhinebothrium
(Cestoda: Tetraphyllidea) from South American Freshwater Stingrays. F.B. REYDA*, Department of
Ecology and Evolutionary Biology, University of Connecticut, Storrs CT, USA, and F.L. MARQUES,
Departamento do Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
202
ABSTRACTS
Neotropical freshwater stingrays (Potamotrygonidae) host a diversity of metazoan parasites. Within this
parasite assemblage, the cestodes are the most speciose, consisting of 22 species of six genera of the
elasmobranch cestode orders Tetraphyllidea and Trypanorhyncha. Among these cestode genera, Rhinebothrium was potentially the most poorly understood until the current study. Previously, only one species
of this predominantly marine genus had been described from potamotrygonids; Rhinebothrium paratrygoni had been reported from eight potamotrygonid species. Recent collections of nearly 500 stingray
specimens representing as many as 29 species of potamotrygonids in the Amazon and Rio de la Plata
River basins facilitated morphological and molecular study of Rhinebothrium diversity in the Potamotrygonidae. Histology, light and scanning electron microscopic analyses revealed numerous new species of
Rhinebothrium. These species differed in size, and in discrete morphological features of the cirrus, vagina,
and bothridia, as well as in patterns of proglottization. These varied in their degree of host specificity.
Molecular sequence data of nuclear 28s rDNA and mitochondrial cytochrome oxidase I supported the
species boundaries determined based on discrete morphological characters. The sequence data, however,
revealed low levels of divergence between species that had been distinguished based solely on continuous
features, such as total length and number of proglottids. A preliminary phylogenetic hypothesis for the
freshwater species and selected marine species of Rhinebothriumsuggests that Rhinebothriummay have
colonized South America on more than one occasion. The sister taxon of these groups, however, remains
unclear. This study provides evidence that the diversity of Rhinebothrium in freshwater stingrays is greater
than previously documented, and that the host specificity of Rhinebothriumspecies, while greater than
previously documented, is more relaxed than that observed in marine tetraphyllideans.
339
Host Phylogeny as an Explanation of the Diversification of Tetraphyllideans in Neotropical Freshwater
Stingrays: A Case Study with Rhinebothroides. F.P. MARQUES*, N.M. LUCHETTI and V.M. BUENO,
Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
The derivation of neotropical freshwater stingrays (Potamotrygonidae) from marine ancestors resulted in
a complex fauna of parasites mainly represented by tetraphyllideans. While some of the parasite genera in
potamotrygonids, like their hosts, clearly represent lineages of marine groups that have colonized freshwater (e.g., tetraphyllidean cestode genera Acanthobothrium and Rhinebothrium), the relationships of
other endemic genera that diversified within potamotrygonids (e.g., Potamotrygonocestus and Rhinebothroides) remain unclear. Tetraphyllideans are known to exhibit high host specificity in marine elasmobranchs, a pattern that has been expected for freshwater stingrays in the Neotropics. Although there are
19 valid species of potamotrygonids, recent surveys in South America suggest that the diversity of
potamotrygonids has been greatly underestimated. The large number of undescribed species of potamotrygonids encountered during surveys has generated the expectation of a parallel increment of tetraphyllidean diversity. Despite the recognition of new lineages of tetraphyllideans in potamotrygonids, the
pattern of diversification does not parallel what has been reported for marine elasmobranchs; multiple
species of tetraphyllideans per elasmobranch species, each of which are strictly host specific. Here we
address our preliminary results of the search for new lineages of Rhinebothroides within two presumed
species complexes: Rhinebothroides glandularis and Rhinebothroides freitasi. A phylogenetic hypothesis
based on three mitochondrial genes for more than 100 terminals of potamotrygonids, including most of
the nominal species and some undescribed ones, is presented. Our results concerning morphological
diversification within Rhinebothroides are discussed on the basis of host phylogeny. Recent diversification
and possible introgression of host lineages seem to be the best explanation for the patterns we have been
found in tetraphyllideans inhabiting freshwater potamotrygonids.
340
Tapeworms (Cestoda: Proteocephalidea) of Firewood Catfish Sorubimichthys planiceps (Siluriformes:
Pimelodidae) from the Amazon River: A Survey of Species and Key to Their Identification. A. DE
CHAMBRIER, Département des Invertébrés, Muséum d’Histoire Naturelle, Geneva, Switzerland, and
T. SCHOLZ*, Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská,
„eské Bud•jovice, Czech Republic.
On the basis of examination of type-specimens and material recently collected in the Amazon River in
Brazil and Peru, a survey of proteocephalidean cestodes found in the pimelodid firewood catfish Sorubi203
ABSTRACTS
michthys planiceps (Spix and Agassiz) is provided and their taxonomic status is discussed. It is concluded
that Woodland (1933, 1934), who described five species of conspecific cestodes from “peixe lenha,”
designated as long-whiskered catfish Platystomatichthys sturio (Kner), apparently misidentified the fish
host, which was almost certainly S. planiceps. The following taxa have been described from this fish host:
Monticellia lenha Woodland, 1933; Nomimoscolex lenha (Woodland, 1933) (syn. Proteocephalus lenha
Woodland, 1933); Peltidocotyle lenha (Woodland, 1933) (syns. Othinoscolex lenha Woodland, 1933 and
Othinoscolex myzofer Woodland, 1933); and Monticellia megacephala Woodland, 1934. In addition, two
species, one of Chambriella and one of Choanoscolex, which may be new for science, were also found in S.
planiceps, which thus hosts as many as six species of proteocephalidean cestodes.
341
Epidemiology Test in Pregnant Mothers and Their Newborns Who Live in Endemic and Non-endemic
Zones of Chagas Disease. J.C. BARRERA-ORTÍZ*, L.V. JIMÉNEZ-ROJAS, G. CAMPOS-VALDEZ, R.
SÁNCHEZ DE LA LUZ, M.L. CABALLERO-GARCIA and E. JIMÉNEZ-CARDOSO, SR., Laboratorio de
Investigacion en Parasitologia, Hospital Infantil de México Federico Gomez, México DF, México.
Introduction: T. cruzi has three ways of transmission, of which one is congenital, with an incidence of
6%, and 17% of those pregnant living in endemic areas positives for Chagas. Newborns are symptomatic
in 20%; the most frequent symptoms are: an Apgar score of less than seven in a minute, low birth
weight, premature birth in 45%, hepatoesplenomegaly, and a decrease in the newborn’s cranium diameter. Objective: To know the most frequent symptoms in newborns living in the endemic zones for this
disease related to Chagas pathology. Material and Methods: Sixty blood samples of pregnant woman and
their newborns at 32 gestational weeks were obtained in the National Perinatoloy Institute in México
City, and 60 and 70 samples of mothers and newborns with the same characteristics were obtained from
Oaxaca, Oaxaca and from Guadalajara, Jalisco, respectively. Information regarding age, origin zone,
number of previous pregnancies, week of the present pregnancy, placental membrane rupture and blood
transfusion were obtained. In the newborns: sex, Apgar score, Capurro age, weight, body size, cranium
diameter, hepatic, and splenic, digestive and cardiac alterations. Three ml of umbilical cord blood was
used for PCR to search for T. cruzi; 5 ml of maternal blood was used to determine by ELISA IgG
antibodies to T. cruzi. Results: Of all mothers from the three zones, the most common details were:
maternal age 21–25 years old (22.1%), rural zone (91.4%), one previous pregnancy (23.2%), 38–39
weeks gestation (23.2%), no placental membrane rupture (76.3%), negative blood transfusion (88.4%).
In the newborns: masculine sex (57.8%), Capurro age 38–39 weeks (32.6%), Apgar score less than
seven in one minute (11.1%), weight to 3–3.5 Kg (36.8%), body size 50 cm (49%), cranium diameter
33–35 cm (48.9%), hepatic, splenic, digestive and cardiac alterations (100%). PCR for T. cruzi was
positive for three newborn samples (1.6%) and 30 positive ELISA samples (15.7%). Conclusions: The
positive newborns present clinical details compatible with Chagas, and the mothers of the three positive
children were seronegative, probably due to an acute infection.
342
Presence of T. cruzi in Pregnant Women and Newborns in Endemic Regions of México. G. CAMPOSVALDEZ*, J.C. BARRERA-ORTÍZ, L.V. JIMÉNEZ-ROJAS, R. SÁNCHEZ DE LA LUZ, M.L. CABALLEROGARCIA and E. JIMÉNEZ-CARDOSO, SR., Laboratorio de Investigación en Parasitología, Hospital
Infantil de México Federico Gomez, México DF, México.
Introduction: In endemic regions of Latin American, the congenital transmission of Trypanosoma cruzi
affects up to 10% of pregnant infected women. In México, the prevalence of vertical transmission has
been poorly studied; only one case of congenital infection was published in 1998. It is important to
detect the T.cruzi congenital cases in endemic regions of México because early recognition is essential for
effective treatment. Methods: Randomly, 165 mother and their delivered babies in two hospitals of
endemic regions (the states of Guadalajara and Oaxaca) and one hospital of a non-endemic region
(México City) were studied. Umbilical chord blood from newborns was used to search for circulating
parasites by microhematocrit and PCR with primers specific for T. cruzi. Each mother was analyzed
serologically for anti-T. cruzi antibodies by ELISA and Chagas Stat Pack Kit. Results: We detected 21.2%
(35/165) of the mothers as seropositive by ELISA and 11% (19/165) by Chagas Stat Pack Kit; both
methods only agreed 7.3% (12/165) were seropositive. Furthermore, we detected 1.8% (3/165) new204
ABSTRACTS
borns by PCR positive, although they were negative in microhematocrit. Conclusions: A high relative
seroprevalence of T.cruzi infection in pregnant women was detected, and congenital cases were 1.8%.
343
Seroprevalence of Gnathostomosis in Guerrero, México. M. CABALLERO-GARCIA*, Laboratorio de
Investigación en Parasitologia, Hospital Infantil de México Federico Gomez, México DF, S. LÓPEZSILVA, Laboratorio Estatal del Estado de Salud Pública Dr. Galo Soberon y Parra, Acapulco, Guerrero,
and E. JIMÉNEZ-CARDOSO, SR., Laboratorio de Investigación en Parasitologia, Hospital Infantil de
México Federico Gomez, México DF, México.
Introduction: In Guerrero, México, gnathostomosis is an important emerging health problem, because
the people are used to eating freshwater fishes that can be infected with Gnathostoma binucleatum, and
which are served in the preparation of food as “ceviche,” a famous, traditional Mexican raw-fish dish.
Objective: The purpose was analyze the seroprevalence of human gnathostomosis in different localities of
Guerrero, México, located on the southern Pacific coast, a geographic area recognized as endemic for the
parasite. Methods: An aqueous extract of advanced third-stage G. binucleatum (AdvL3) and adult worms
of Ascaris lumbricoides, Ancylostoma caninum and Toxocara canis were homogenized with liquid nitrogen
and diluted in 10 mM Tris buffer with a mixture of protease inhibitors. The supernatants were used as
the source of antigen and the protein content was estimated by the Bradford method and kept at -20°C
until used. A total of 100 human sera from different areas of Guerrero, México were analyzed. Anti-G.
binucleatum antibody screening was done by ELISA and immunoblot was used for cross reactivity.
Results: Anti-G. binucleatum antibodies were found in 10 sera. Immunoblot with sera from ELISA
positive results showed proteins with molecular weight of 210, 110, 90 and 40 kDa, but cross reactions
were present with antigens of T. canis, A. lumbricoides and A. caninum. When these sera were absorbed
with the cross reactive antigens, only two sera remained positive to protein of 40 kDa specific to G.
binucleatum. Conclusion: A prevalence of 2% of gnathostomosis was detected in the studied area; it is
important to be careful in the diagnosis and consider cross reactions with other migrating larval parasites
to prevent problems in the definitive diagnosis.
344
Genetic Diversity of Trypanosoma cruzi Strains Isolated from México. L.V. JIMÉNEZ-ROJAS*, J.C.
BARRERA-ORTÍZ, G. CAMPOS-VALDEZ, R. SÁNCHEZ DE LA LUZ and E. JIMÉNEZ-CARDOSO, SR.,
Laboratorio de Investigación en Parasitologia, Hospital Infantil de México, México DF, México.
Introduction: T. cruzi strains have a wide variability in biological properties, which are probably associated with its very broad host range. T. cruzi can infect a wide variety of vertebrate hosts, triatomine
insect species, and can be parasitized in almost all tyes of cells. The heterogeneity can be demonstrated
using molecular and biochemical techniques, such as pulse field gel electrophoresis (PFGE). We evaluated the heterogeneity or genetic variability of eight T. cruzi isolates obtained from some states of
México, maintained in culture for differents periods of time. Methods: Seven strains of T. cruzi isolated
from infected humans and one triatoma infestans (a strictly domiciliary vector) were evaluated by
morphology and growth curves in LIT medium. To determine the genetic diversity, we analyzed the
electrophoretic patterns generated by PFGE hybridized with a nuclear DNA probe from the parasite.
Results: PFGE showed a greater discriminative level to enable resolution of 20–23 bands ranging from
0.36 to 3.7 Mbp, depending on the T. cruzi strain. Six different profiles were found among eight isolates,
with only two of them present in more than one isolate. None of our isolates showed identity with the
reference strain (CLB). Conclusions: Our studies indicate that the electrophoretic patterns of analyzed
Mexican T. cruzi strains show enough genetic diversity to allow the identification of different clones or
clone clusters among isolates.
345
Expression of Glucosamine 6-phosphate Isomerase, Ubiquitine and Cyst Wall Protein Genes During
Encystment of Giardia intestinalis by Real-time PCR Assay. E. JIMÉNEZ-CARDOSO, SR.*, L. ELIGIOGARCIA, JR., M. CRISOSTOMO-VAZQUEZ, JR. and A. FLORES-LUNA, Laboratorio de Investigacion en
Parasitologia, Hospital Infantil de México Federico Gomez, México DF, México.
205
ABSTRACTS
The cyst wall of the parasitic protozoan, Giardia intestinalis, is formed by a polymer of N-acetylgalactosamine, the precursor of which is synthesized by an inducible enzyme pathway. The first enzyme in this
pathway, glucosamine 6-phosphate isomerase, is transcriptionally regulated. This enzyme appears only
after Giardia trophozoites are induced to start the production of cyst wall components after bile is added.
All eukaryotes contain multiple copies of ubiquitin genes, most of which are arranged in fusions coding
for either polyubiquitin or ubiquitin-ribosomal protein constructs; the former are normally under the
control of a heat shock promoter. Experimental evidence suggests that Giardia contains just one ubiquitin gene, which consists of a single copy of the coding sequences and the expression of which is not
enhanced by heat shock. The aim of this study was to determine the level of expression of genes corresponding to glucosamine 6-phosphate isomerase (g6pi), ubiquitine (ub) and cyst wall protein (cw)
during differentiation of Giardia intestinalis into cysts by time-real PCR. Methods: Eighteen axenic
strains (nine resistant to albendazole and nine sensitive) were cultured in TYI S 33 until fully grown. The
cultures (72 h) were removed and the adherent trophozoite monolayer was supplemented with complete
encystations medium TYI-S-33 pH 7.8 supplemented with 0.25 mg of porcine bile per ml and 0.55 mg
of lactic acid per ml. Giardia thophozoites cultures were kept in encystations medium. Cells were harvested to 24, 48 and 72 h and total RNA was extracted to perform reverse transcription PCR to obtain a
double strand DNA, which was used as a substrate in time-real PCR using specific primers for each
gene. Results and Conclusions: Levels of expression show that g6pi increased at 48 h, and 72 h after
time 0; ubiquitine behaved similarly, as did cyst wall protein, which kept a high level of expression until
72 h.
346
Genotyping of Giardia intestinalis Isolated from Dogs by Restriction of β-giardin Gene. L. ELIGIOGARCIA, JR.*, E. JIMÉNEZ-CARDOSO, SR. and A. CORTES-CAMPOS, Laboratorio de Investigacion en
Parasitologia, Hospital Infantil de México Federico Gomez, México DF, S.D. COTA-GUAJARDO and N.
CARCAMO-ARÉCHIGA, Universidad de Sinaloa, Culiacan, México.
Giardia intestinalis is a parasitic protozoan found in the intestines of humans and many animals, including dogs. This microscopic parasite clings to the surface of the intestine or floats freely in the mucous.
The prevalence of Giardia in dogs is unknown; however, rates of 5–50% have been suggested, depending
of the quality of sanitary services. It is assumed that Giardia can be transmitted from one animal to
another and to humans. The major genotypes of G. lamblia that are infective to humans are assemblages
A and B; A is associated with a mixture of human and animal isolates, and B is predominately associated
with human isolates. The greatest potential for zoonotic transmission of Giardia is with assemblage A
genotypes. Domestic animals, wildlife, and possibly pets act as reservoirs of Giardia. The aim of this
study was to determine the genotype of Giardia isolates from dogs according to the restriction pattern
with HAE III enzyme in order to identify group A. Methods: Seventeen canine fecal specimens were
obtained from individuals six years old, all positive for Giardia. DNA was extracted from the stool
samples by phenol-chloroform extraction, then a PCR amplification was done with -giardin primers. The
amplification product was digested with HAE III enzyme and the product was run in an agarosa gel
electrophoresis. Results and Conclusions: The obtained amplification product was approximately 2,500
pb and two kinds of patterns corresponding to positive and negative restriction were obtained. Most
samples were included in genotype AII; this genotype has been reported from humans and, in this case,
from dogs, which supports that Giardia causes a zoonosis.
347
Polymorphism of the β-giardin Gene in Albendazole-resistant Strains of Giardia intestinalis. L. ELIGIOGARCIA, JR.*, E. JIMÉNEZ-CARDOSO, SR, A. CORTES-CAMPOS and A. FLORES-LUNA, Laboratorio
de Investigacion en Parasitologia, Hospital Infantil de México Federico Gomez, México DF, México.
Albendazole is one of the most common drugs for the treatment of giardiasis; however, some organisms
have been isolated from infected patient with resistance to it. About 20% of the therapeutic target is the
cytoskeleton of Giardia, specifically tubulins. Some theoretical mechanisms explain the induction of
drugs resistance, however, the role of the β-giardin gene has not been studied. β-giardins are included in
a family of alphahelicoidal proteins that belong to the ventral disc; they are specific to Giardia and they
are considered important in the mechanism of resistance induction. The aim of this study was to deter206
ABSTRACTS
mine the growth and the polymorphism of the β-giardin gene in albendazole-resistant strains of Giardia
intestinalis induced experimentally and compare them with sensitive strains. Methods: Resistance in nine
axenic strains was induced by the addition of different concentrations of albendazole, the growth of each
of the strains was monitored, DNA was extracted in 100%, and cultures and a Polymerase Chain Reaction using β-giardin primers were made. The amplification product was restricted with Hae III and
submitted to agarosa gel electrophoresis. The amplicon was sequenced and analyzed by Clustal Wallis
Results: We obtained resistance in the axenic strains of Giardia. Analysis of the generation time showed
differences in sensitive and resistant strains, and that growth of sensitive strains was faster than resistant
ones. There were no differences between isolates obtained by digestion with Hae III enzyme; the
sequencing and the respective analysis of samples with informatic softwares of analyzed sequences
showed 95.7% similarity among them; and the differences have no relationship with the sensitive and
resistant strains. Conclusions: It is necessary to perform an assay with clinical samples of infected patients
resistant to albendazol treatment, since this may constitute an important public health problem.
348
Polymorphism Ribosomal Protein L30 Gene in Entamoeba histolytica cDNA Isolated from Liver Abscess
in Hamster and Monoxenic Culture. M. CRISOSTOMO-VAZQUEZ, JR.*, L. ELIGIO-GARCIA, JR., V.
MARAVELEZ-ACOSTA, III, J. HERNÁNDEZ-GARCIA and E. JIMÉNEZ-CARDOSO, SR., Laboratorio de
Investigacion en Parasitologia, Hospital Infantil de México Federico Gomez, México DF, México.
Substrative hybridization (SH) was carried out from Entamoeba histolytica HM-1:IMSS liver abscess in
hamsters and monoxenic cultures. Ribosomal protein L30 gene was obtained by SH; this protein
belonged to amoebas that produced abscess in hamster liver. The protein can inhibit cell-free translation
of mRNAs, suggesting that it plays a regulatory role in the translation apparatus. Our aim in this
investigation was to study if there were polymorphisms in the 216 bp fragment that will permit finding
differences between parasites from monoxenic cultures and liver abscesses. Objetive: To determine
polymorphism of the amplified sequence corresponding ribosomal protein L30 gene by means of
restriction endonuclease digestion from Entamoeba histolytica trophozoites from monoxenic cultures and
liver abscesses. Materials and Methods: Human stool samples with Entamoeba histolytica cysts were
collected. Each sample was cultured monoxenically in Robinson’s medium. These trophozoites were
intrahepatically inoculated into hamsters; eight days post-inoculation the amoebas were recuperated from
liver abscesses and then cultured again. DNA was isolated by phenol-chloroform and was amplified with
oligonucleotides designed by a primer 3 program. A 216 bp fragment of ribosomal protein L30 gene
was obtained from a cDNA library by substractive hybridization of amoebas that produced liver abscesses in hamsters and amoebas did not. Sequences were analyzed with Secuence Manipulation to obtain
the amplicons restriction map. Results: Ribosomal protein L30 gene was amplified from monoxenic
Entamoeba histolytica isolates. Restriction endonuclease analyses of amplicons was done in silico; we
detected a restriction site in the gatc 7 belonging to non-abscess-producing amoebas and in the 91 gatc
by MboI and NdeII enzymes for abscess-producing amoebas. Conclusion: Our results demonstrated that
ribosomal protein L30 gene restriction enzyme analyses using MboI and NdeII enzymes could classify
isolates related to analysis of the strains that produce abscess.
349
Genetic Difference of E. histolytica by Subtractive Hybridization. M. CRISOSTOMO-VAZQUEZ, JR.*,
L. ELIGIO-GARCIA, JR., V. MARAVELEZ-ACOSTA, III, J. HERNÁNDEZ-GARCIA and E. JIMÉNEZCARDOSO, SR, Laboratorio de Investigacion en Parasitologia, Hospital Infantil de México Federico
Gomez, México DF, México.
Most Entamoeba in humans remain asymptomatic, and a small portion of E. histolytica infections penetrate the intestine and are capable of disseminating to organs and developing liver abscesses. In order to
understand these differences, we are using subtractive libraries to identify genes that are expressed
differentially in these two kinds of trophozoites. We are comparing the cDNA expression between E.
histolytica isolated from liver abscesses of infected hamsters and those grown under normal culture
conditions. Material and Methods: Amoebas (1 x 106) in a volume of 200 µL were injected into the left
liver lobe of hamsters. Eight days later, the animals were sacrificed and their livers were removed. The
livers were sliced and transferred to TYI-S-33 medium. After eight days, the amoebas were harvested, the
207
ABSTRACTS
cDNA was prepared (A), and cDNAs from amoebas cultivated a longer time were used (B). Homologous cDNAs were hybridized on a nylon membrane and in a free solution cDNA that did not hybridize
was recovered, then the sequences was amplified with primers T (12)CG, T (12)GC, T (12)GC, T (12)AT, T
CT. The amplified cDNA was separated on an agarose gel, carefully excised different bands and
(12)
purified. cDNAs were sequenced using an Amplitaq BigDye terminator kit. Gene and protein homology
searches were performed using the Entamoeba histolytica genome database. Results: Four sequences was
found, one of them with homology to the E. histolytica genome, encoding 60s ribosomal protein L30,
and in other sequences no similarity was found. These sequences belonged to amoebas that develop
hepatic abscesses in hamsters. Two sequences had homology with hypothetical proteins. Discussion: The
subtraction method used to identify transcripts induced by changes in growth conditions was useful to
identify gene differences in E. histolytica trophozoites between isolates from hamster liver and those
cultured a long time. The relevance of this work is the evidence of different sequences in these two kinds
of trophozoites.
350
Eimeria falciformis Effect on T Helper 2-associated Eosinophilic Responses Induced by Nippostrongylus
brasiliensis Infection. Z.A. AL-DAHWI* and L.F. MAYBERRY, Department of Biological Sciences, The
University of Texas, El Paso TX, USA.
This study reports bone marrow and peripheral blood eosinophil responses of Balb/c mice infected with
N. brasiliensis and/or E. falciformis. Group 1 mice served as controls. Group 2 mice were given 500 L3 of
N. brasiliensis. Group 3 mice were administered 750 E. falciformis oocysts. Mice in group 4 were infected
with N. brasiliensis and six days later administered E. falciformis. Tail blood was collected from all mice on
days 0, 6 and 14 PI; femoral bone marrow was collected on day 14. Eosinophils/mm3 were quantified
using the Unopette® Test. Preliminary data analysis suggest that blood and bone marrow eosinophils
were elevated on day 14 PI in mice infected singly with N. brasiliensis. In concurrently infected mice,
however, on day 14 PI, reduced peripheral blood eosinophils correlated with elevated helminth-induced
bone marrow eosinophilia. Inasmuch as eosinophilia represents a typical helminth effector mechanism
and has been shown to be modulated by the mouse coccidium in this study, our results suggest that E.
falciformis-mediated immunoregulation underlies impairment of eosinophil mobilization following prior
exposure to the potent T helper (Th) 2 inducer, N. brasiliensis. We hypothesize that the induction of an
interleukin (IL)-12-driven Th 1 response is suppressing an IL-4-associated Th 2 cell development in
hosts co-infected with both parasites. It has been shown that STAT 6 is crucial in the IL-4 signaling
mechanism for development of the Th 2 subset. Thus, this concurrent infection model presently is being
used to compare immunomodulation of eosinophilic responses in Balb/c STAT 6 gene knockout mice
(STAT 6-/-) with that in wild-type (STAT 6+/+) counterparts of matched age and sex. (This research was
supported by NIH RCMI Grant 5G12RR008124 and a Coldwell Foundation Grant.)
351
Thymus Atrophy in BALB/c Mice Infected with Plasmodium chabaudi chabaudi AS. G. ORTÍZESTRADA, L.H. FABILA-CASTILLO and L.E. SÁNCHEZ-TORRES*, Department of Immunology, National
School of Biological Sciences, IPN, México DF, México.
Alterations in percentage and absolute number in lymphoid subpopulations presented in the thymus of
BALB/c mice during a primary infection by Plasmodium chabaudi chabaudi AS were studied, as well as
the presence of immature T CD4+CD8+ lymphocytes in blood, spleen, inguinal and mesenteric lymph
nodes by flow cytometry and corticosterone in serum by radioimmunoassay. Bax, bcl-2 and fas expression
in thymuses by real-time RT-PCR techinique also was evaluated. From the beginning of the infection and
mainly after the day of maximum parasitemia, the thymus showed a diminished size with an important
reduction in the percentage and absolute number of total lymphocytes, the most affected being the T
CD4+CD8+ subpopulation. Alterations detected were transitory since the thymus recovered towards
day 18 posinoculation. No significant increase in double positive T lymphocytes in blood, spleen,
inguinal and mesenteric lymph nodes were observed. Corticosterone level was increased during the
infection with a similar kinetic to that of the parasitemia. Overexpression of bax and fas, and downstream
of bcl-2 were induced in the thymus of infected mice. A maximum effect was detected by days 12–15
post-inoculation. Our results suggest that during infection with P. chabaudi chabaudi AS, the reduction in
208
ABSTRACTS
thymic T CD4+CD8+ population is not due to their migration to blood, spleen, inguinal and mesenteric lymph nodes. High levels of corticosterone and upstream of bax and fas, as well as downexpression
of bcl-2, allows us to infer that thymic atrophy is caused by an increase in apoptosis levels in the thymus.
(Sánchez-Torres and Fabila-Castillo are supported by EDI-IPN and COFAA-IPN, Ortiz-Estrada is
supported by CONACYT.)
352
Development and Evaluation of an HDP2 Seminested-PCR for Detecting Taenia solium DNA in Human
Cerebrospinal Fluid: A New Tool to Identify Solved Neurocysticercosis? M. HERNÁNDEZ*, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México, L.M.
GONZÁLEZ, Departamento de Parasitología, Instituto de Salud Carlos III, Centro Nacional de Microbiología, Majadahonda, Spain, A. FLEURY, Instituto Nacional de Neurología y Neurocirugía, SSA,
México DF, B.I. SAENZ, M. AVILA, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México, R.M. PARKHOUSE, Gulbenkian Institute for Science, Oeiras,
Portugal, L. HARRISON, Department of Tropical Animal Health, Sir Alexander Robertson Centre for
Tropical Veterinary Medicine, Easter Bush Veterinary Centre, University of Edinburgh, Roslin, Midlothian, U.K., E.L. SCIUTTO, Departamento de Inmunología, Instituto de Investigaciones Biomédicas,
UNAM, México DF, México, and T. GARATE, Departamento de Parasitología, Instituto de Salud Carlos
III, Centro Nacional de Microbiología, Majadahonda, Spain.
Human neurocysticercosis (NC) is caused by Taenia solium larvae lodged in the central nervous system.
NC is often diagnosed based on imaging studies, but in particular cases diagnosis remains elusive. To
overcome this, a new seminested polymerase chain reaction (Sn-PCR) assay for detecting cysticercal
DNA in the cerebral spinal fluid (CSF) of NC patients was developed. HDP2 primers allow the detection of 174 attograms of Taenia solium.The diagnostic value of HDP2 Sn-PCR in NC was evaluated in
samples from 88 neurological patients. HDP2 Sn-PCR detected up to 71% of the NC patients with
vesicular extraparenchymal cysterci and 16.7% of those with damaged cysticerci. DNA was not detected
in the 36 CSF from non-NC neurological patients, raising 100% of specificity. These results demonstrate
the feasibility of this method to specifically detect cysticercal DNA in CSF of neurological patients,
offering a new tool for diagnosis of and research on NC.
353
Cytokines and Nitric Oxide During Amoebic Liver Abscess Development in Immunized Hamsters. J.
PACHECO-YEPEZ, Electron Microscopy Laboratory, Mexican Faculty of Medicine, ULSA, México DF, S.
GALINDO-GOMEZ*, V. TSUTSUMI and M. SHIBAYAMA, Department of Experimental Pathology,
CINVESTAV-IPN, México DF, México.
Entamoeba histolytica is a protozoan parasite that causes human intestinal amoebiasis and liver abscess.
The amoeba has the ability to induce an inflammatory reaction, which produces cytokines by different
cell lines, including naive macrophages. In vitro studies have shown that Kupffer cells, peritoneal and
spleen macrophages derived from E. histolytica-infected animals do not release TNFα. Other studies have
demonstrated that spleen and lymph node cells from gerbils with amoebic liver abscess express a little
amount of IL-2, IL-4 and TNFα during the acute phase. Also, the TNFα produced by the activated
peritoneal macrophages increased the nitric oxide (NO) dependent cytotoxicity against E. histolytica in
vitro. Macrophages from amoebic lesions, however, did not produce NO or damage amoebae. The in vivo
role of cytokines and NO during invasive amoebiasis is not understood completely. Moreover, there are
no studies related to the presence, localization and participation of cytokines and NO during the first
steps of E. histolytica arrival in the liver. The objective of the present study was to determine the presence
of TNFα, INFγ and NO in situ during amoebic liver abscess development in the hamster. These molecules were determined by immunohistochemistry in liver samples from animals immunized and nonimmunized with amoebic crude extract. The results showed that amoebic antigen activates the production of TNFα and INFγ. This phenomenon was transitory and present only during the early stages of the
amoebic abscess development. Moreover, the presence of these cytokines did not arrest the normal
evolution of amoebic liver abscess. On the other hand, NO was not present at any time of amoebic lesion
evolution, even in the animals previously immunized. It is suggested that local suppression of these
molecules may contribute to the E. histolytica survival.
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354
Impaired Pro-inflammatory Cytokine Production and Th1 Biasing Ability of Dendritic Cells Exposed to
Taenia Antigens. L.I. TERRAZAS-VALDÉS*, Unidad de Biomedicina, FES-Iztacala, UNAM, C.A.
TERRAZAS, I. RIVERA-MONTOYA and M. RODRÍGUEZ-SOSA, Unidad de Biomedicina, FES-Iztacala,
UNAM, México.
A key feature of helminth infections is the induction of Th2-biased immune responses in their hosts.
Although the mechanisms involved in this phenomenon are not yet clearly defined, antigen-presenting
cells (APC) could play an important role in this process. Dendritic Cells (DC) recognize motifs that are
conserved between large classes of microbial pathogens and bind to germline-encoded receptors. Among
these receptors, the family of Toll-like receptors (TLR) is the main pathway known to be involved in
maturating and inducing inflammatory cytokines from DCs. The PAMPs described to date, mostly in
intracellular pathogens, drive Th1 type responses largely through these Toll-like receptors. By contrast,
the result of the first interaction between DCs and helminth parasites and their antigens is less very well
known. In fact, most of the advances in the interaction between helminths and innate immunity has been
reached through the research on nematodes and trematodes, whereas research on the activity of cestode’
antigens on innate immunity and Th2 polarization remains unknown. In an attempt to dissect mechanisms that lead to immune modulation in experimental murine cysticercosis, we have used bone marrowderived DC exposed to both Taenia excreted/secreted glycoproteins and Taenia soluble extracts and
examined their role as APCs, as well as in the modulation of DC responses to pro-inflammatory stimuli.
We found that Taenia antigens had the ability to suppress DC production of TNF-α and IL-12 in
response to several inflammatory molecules such as LPS, CpG and Toxoplasma soluble antigen. Furthermore, Taenia-exposed DC displayed increased ability to suppress IFN-γ production but maintained the
IL-4 production on CD4+ DO11.10 cells in response to OVA-peptide. Finally, Taenia-exposed DC
displayed lower CCR7 expression. Together our results reflect the potential ability of T. crassiceps antigens
to modulate inflammatory responses mediated trough DC-activation to non-related pro-inflammatory
molecules.
355
Regulatory T Cells Induction by Parasitic Antigens. Y. FLORES-GARCÍA*, L. PÉREZ-CASTILLO, L.
BAYLÓN PACHECO, A. ANGEL, J.L. ROSALES-ENCINA and P. TALAMÁS-ROHANA, Departamento de
Patología Experimental, CINVESTAV-IPN, México.
T regulatory (Treg) cells are critical for establishing self-tolerance, controlling inflammatory responses
and maintaining immune homeostasis. Treg cells are divided into naturally arising Treg cells and IL-10
Treg cells. They have been characterized by the presence of surface markers such as CD4, CD25, and
Foxp3, and TGF-β and IL-10 secretion, the last one being an immunomodulatory cytokine that has a key
role in suppressing Th1 type immune responses. Two parasitic antigens with immunomodulatory activity,
L220 and Am230 from E. histolytica and T. cruzi, respectively, have been described. The aim of this study
was to determinate if these proteins were able to induce Treg cells (CD4+CD25+) and IL-10 production. IL-10 was measured by ELISA from culture supernatants and the presence of Treg cells was
analyzed by FACS in spleen cells from L220 or Am230 immunized mice that were re-stimulated in vitro
with the corresponding antigens. BALB/c mice were immunized three times with 10 µg of Ag, three
weeks apart for L220 and one week apart for Am230. Two weeks after the last immunization, cell
proliferation assays were performed with spleen cells in the presence of the corresponding antigens
(L220 or Am230). Results showed that spleenocytes secreted IL-10, being more abundant in the case of
cells from mice immunized and stimulated with Am230 (430 pg/ml) in comparison with those cells from
mice immunized and stimulated with L220 (70 pg/ ml). Regarding the presence of CD4+CD25+Treg
cells, there was an increase in this population in cells from mice immunized with Am230 and stimulated
with Am230 in vitro, from 3.79 to 7.65%; whereas, in mice immunized with L220, but without in vitro
stimulation, there was 10.93 % of CD4+CD25+Treg cells in comparison with 5.39% in non-immunized mice. These results suggest that parasitic proteins may induce CD4+CD25+Treg cells as a mechanism for modulation of the host immune response in order to favor the establishment of the infection.
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ABSTRACTS
356
Histological and Immunohistochemical Detection of Leishmania (L.) chagasi in the Skin of Infected
Dogs. W.A. STARKE-BUZETTI*, N.G. QUEIROZ, R.S. VIVEIROS, Departamento de Biologia e Zootecnia, FEIS/UNESP, Ilha Solteira, São Paulo, Brazil, A.F. NORONHA, JR., Centre of Zoonosis Control,
Ilha Solteira, São Paulo, Brazil, R.Z. MACHADO and T.F. OLIVEIRA, Departamento de Patologia
Veterinária, FCAV/Jaboticabal, São Paulo, Brazil.
Canine visceral leishmaniasis (CVL) is caused by Leishmania (L.) chagasi, endemic for humans and dogs
in many regions of Brazil. The purpose of this study was to evaluate the histological and mmunohistochemical methods for demonstration of Leishmania in skin of symptomatic as well as asymptomatic
Leishmania-infected dogs. These methods also were compared with other currently methods used for
diagnosis of this disease in dogs such as IFAT and ELISA. Biopsies of normal or lesion skins from 34
dogs were processed for routine histochemical and immunoistochemical techniques. Dogs with high
serological antibody titer for Leishmania and high parasite load in the skin showed a great number of
infected macrophages for all layers of the skin: below the epidermis, superficial, midi and deep dermis, in
the hypodermis and around the smooth muscle cells. The skin biopsies from asymptomatic dogs had
negligible, if any lesions, and parasite direct examination showed that the most of these dogs (62.5%)
were negative or suspect, but three (37.5%) were positive in skins without any dermatological alterations. In oligosymptomatic dogs, 14 (82.3%) showed discrete parasite load, particularly in lesion skins,
but the clinically normal skin of one dog revealed strong immunodetection of Leishmania amastigotes. In
symptomatic group, 100% of dogs had several forms of cutaneous alterations with strong parasite loud
in their lesion skins. In comparison with serological tests (IFAT or ELISA), the immunohistochemistry
method showed a sensitivity of 65% and specificity of 100% that was higher in lesion than in normal
skins. The results of the present study support on the relevance of infected but asymptomatic dogs in the
epidemiology of CVL because 36% of clinical normal skin harbored detectable parasites. The histological
and immunohistochemistry were proved to be a valuable methods to support the diagnosis of his disease
in addition to serological tests. (Supported by FAPESP and by ASP award Willis A. Reid Jr. Student
Research Fund.)
357
Evaluation of the Efficacy of a Combination of DNA Vaccines Encoding TSA-1 and Tc24 Antigens in
Mice Infected with Trypanosoma cruzi. J.L. TZEC-ARJONA*, P. LÓPEZ-LÓPEZ, W.G. CHALE-BALBOA,
G. SÁNCHEZ-BURGOS, M.J. RAMIREZ-SIERRA and E. DUMONTEIL, Laboratorio de Parasitología,
CIR, Universidad Autónoma de Yucatán, Mérida, Yucatán, México.
Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is one of the main public health
problems in Latin America. Due to the lack of effective drug treatment, we have demonstrated previously that therapeutic DNA vaccines encoding T. cruzi antigens TSA-1 or Tc24 could control partially an
ongoing infection with T. cruzi in ICR and BALB/c mice. In this study, we investigated if treatment with
a combination of both plasmids could increase therapeutic efficacy compared to each plasmid alone in
mice. ICR and C57BL/6 mice were infected with 500 or 20,000 blood parasites, respectively, and treated
at day 5 and 12 post-infection with two doses of DNA vaccines encoding TSA-1 and Tc24 antigens
either alone or in combination. Treatment with the combination of the two plasmids was able to reduce
parasitemia in both ICR and C57Bl/6 mice and reduced cardiac tissue inflammation. Further studies are
underway to evaluate parasite burden in the heart. These results suggest that treatment with a combination of DNA vaccines provides a better therapeutic effect in mice infected with T. cruzi and thus this
treatment presents an attractive alternavive for further evaluation.
358
Efficacy of a DNA Vaccine Against Leishmania mexicana in Golden Hamsters. W.G. CHALE-BALBOA*,
J.L. TZEC-ARJONA, Laboratorio de Parasitologia, CIR, Universidad Autónoma de Yucatán, Mérida,
Yucatán, M. MUT-MARTIN, Laboratorio de Inmunobiología, CIR, Universidad Autónoma de Yucatán,
Mérida, Yucatán, M.J. RAMIREZ-SIERRA, Laboratorio de Parasitologia, CIR, Universidad Autónoma de
Yucatán, Mérida, Yucatán, M.D. GARCIA-MISS, Laboratorio de Inmunobiología, CIR, Universidad
211
ABSTRACTS
Autónoma de Yucatán, Mérida, Yucatán, and E. DUMONTEIL, Laboratorio de Parasitologia, CIR,
Universidad Autónoma de Yucatán, Mérida, Yucatán, México.
The Leishmaniases are a group of diseases caused by protozoan parasites of the Leishmania genus.
Previously, we found that a DNA vaccine encoding L. donovani antigen NH36 could induce protection
against both L. chagasi (visceral leishmaniasis) and L. mexicana (cutaneous leishmaniasis). We further
optimized this vaccine by combining it with a plasmid encoding L. mexicana GP63, which provided
good protection in BALB/c mice. To further evaluate this DNA vaccine, we investigated its efficacy to
induce protection in the golden hamster, an alternative animal model for leishmaniasis. Female golden
hasmters were immunized with two doses of 100 µg of DNA vaccines encoding NH36 and GP63, with
aluminium phosphate as an adjuvant. Control groups received saline solution or the empty plasmid. The
animals were infected with 500 L. mexicana parasites in the hindpaw two–three weeks after immunization. Lesion measurement during 17 weeks indicated that the DNA vaccine was able to reduced lesion
size in vaccinated hamsters, compared to controls. Further evaluation of the immune response in underway, but these results suggest that this DNA vaccine is able to partially protect hamsters against L.
mexicana infection.
359
Differences and Similarities in Human and Porcine Neurocysticercosis: Necropsies Studies. B.I.
SAENZ*, Instituto de Investigaciones Biomedicas, UNAM, A. S. DE ALUJA, Facultad de Medicina
Veterinaria y Zootecnia, UNAM, A. ESCOBAR, G. FRAGOSO, Instituto de Investigaciones Biomedicas,
UNAM, R. PÉREZ-TAMAYO, Facultad de Medicina, UNAM, F. ROSETTI, E.L. SCIUTTO, Instituto de
Investigaciones Biomedicas, UNAM, and A. FLEURY, Instituto Nacional de Neurologia y Neurocirugia,
México.
Cysticercosis can be present in humans and pigs. The presence of parasites in the central nervous system
has been reported in both species. In humans, neurocysticercosis may be present without symptomatology or with varied symptoms like headache or seizures, or a severe presentation such as intracranial
hypertension could be found. Apparently, in pigs, the presence of severe symptoms are not seen and
neurocysticercosis is not a cause of death, as in humans. These differences in symptomatology could be
related to differences in the distribution, location and state of degeneration of cysticerci. A description of
the distribution (frontal, parietal, occipital, temporal lobe and cerebellum), location (subarachnoid space
of the sulci, subarachnoid space of the base, parenchyma and ventricles) and state of degeneration
(vesicular or calcified) of parasites from 22 asymptomatic pig brains and 35 necropsy human cases with
asymptomatic or symptomatic neurocysticercosis were described, and important differences in cysticerci
localization and number between NC in pigs and humans that could underlie differences in symptoms
were found. In humans, symptomatology was related to subarachnoid space of the base cyst location. In
humans, parasites were distributed more frequently in parietal lobes (51.9% vs. 25.9%; p = 0.001),
located in ventricles and subarachnoid space of the base (11.8% vs. 1.6%; p = 0.001 and 25.9% vs. 0%;
p < 0.0001, respectively) and degeneration state were calcified more frequently (75.9% vs. 0%; p <
0.0001) than in pigs. In pigs, calcified nor subarachnoid space of the base parasites was found, and they
were distributed more frequently in occipital lobes (20.5% vs. 3.8%; p < 0.0001), located in parenchyma (44.4% vs. 7.6%; p < 0.0001) and their degeneration state were vesicular more frequently
(100% vs. 24.1%; p < 0.0001) compared to humans. The highest parasite loads were found in pigs,
followed by symptomatic humans, and the least were found in asymptomatic humans. Factors that may
be related with these differences and their relationship with symptomatology will be discussed.
360
Prevalence of Anti-L-220 Antibodies in Individuals Presumably Infected with Entamoeba histolytica in
Chilpancingo, Guerrero, México. R. JAVIER-REYNA*, D. FLORES-ROBLES, J. FLORES DE LA CRUZ,
Unidad de Investigación Especializada en Microbiología, UAG, Guerrero, V. PÉREZ-CASTILLO and P.
TALAMÁS-ROHANA, Departamento de Patología Experimental, CINVESTAV-IPN, México.
Several methods for amoebiasis diagnosis have been developed using a surface protein, the 270 kDa Gal/
GalNAc lectin. Besides this molecule, other surface proteins exist in the trophozoite with potential use
for diagnosis. One of them is the 220 kDa lectin, with specificity for galactose (L220). The search of
antibodies against L-220 can constitute an additional procedure to detect infections caused by this
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ABSTRACTS
parasite. The presence of IgG antibodies against this molecule was analyzed in the sera from 100 patients, clinically diagnosed with amoebiasis. Sera were analyzed by Western blot (1:50 dilution) against
total extract (TE) of trophozoites from the HM1-IMSS strain, as well as against a L220 enriched fraction. Reactive bands were revealed by a secondary goat anti-human IgG (1:5000 dilution) antibody
coupled to alkaline phosphatase. As positive control, sera from mice immunized with L220 were used.
Results showed positive reaction in the TE towards L220 (1.3 % of the sera) as well as towards other
proteins of different molecular weight (100, 116, 120, 123, 130, 140 and 200 kDa) (17.3 % of the
sera). On the contrary, when L220 was used as antigen for Western blot, the efficiency of detection of
positive cases increased up to 20 % with regard to TE; remnant samples (80 %) remained negative
against this protein. In conclusion, individuals infected with E. histolytica present antibodies against
L220, a glycoprotein that can be used as diagnostic method for amoebiasis in zones where a high
prevalence of the disease exists, allowing establishing a clear difference between positive and negatives
samples.
361
Entamoeba histolytica and Entamoeba dispar Interaction with Enteropathogenic Bacteria Synergize
Damage to Epithelial Cells, Amplifying the Inflammatory Response. J.M. GALVÁN MOROYOQUI*, M.
DOMÍNGUEZ ROBLES, E. FRANCO and I. MEZA, Departamento de Biomedicina Molecular
CINVESTAV-IPN, México.
Entamoeba histolytica and Entamoeba dispar colonize the human intestine and feed on bacteria of the
intestinal flora. Under still unknown stimuli, E. histolytica may cause inflammatory colitis and more
severe disease manifestations, while E. dispar does not cause any clinical symptoms. We analyzed the
effects induced by the presence and ingestion of enterobacteria in E. histolytica and E. dispar co-cultured
with epithelial monolayers, as in endemic areas for amoebaisis mixed bacteria Entamoeba infections are
common. A non-pathogenic E. coli strain and the pathogenic ETEC, EPEC, Salmonella enterica serovar
Typhimurium, and Shigella dysenteriae were utilized. Amoebae internalized bacteria at different rates, but
only E. histolytica digested bacteria, with the exception of S. dysenteriae, which survived and was released
from amoebae. Bacteria also survived in E. dispar. E. histolytica virulence and adhesion to epithelial cells
were increased as well as cysteine proteinase activities, in particular after ingestion of S. typhimurium and
S. dysenteriae; E. dispar avirulence was not modified. Pre-culture of epithelial cells with bacteria increased
further cell damage by E. histolytica, after priming an inflammatory response, which enhanced amoebae
and neutrophil migration toward lesioned sites. A Troyian horse-like model is proposed where the
presence of enteropathogenic bacteria and their survival in and release from amoebae would synergize the
inflammatory response of epithelial cells to E. histolytica infection, facilitating tissue invasion. Survival of
bacteria also would be an important factor in recurrent and/or chronic colon inflammation, often diagnosed in patients living in endemic areas for amoebiasis.
362
Trypanosoma cruzi Genotype I Strains Induce Different Inflammatory Reactions in Heart, Skeletal
Muscle and Large Intestine in a Murine Model. A. VIZCAINO-CASTILLO*, R. LIRA, I. MARTÍNEZ and
B. ESPINOZA, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM,
México DF, México.
Several studies in our laboratory have shown biological differences between two Mexican strains both
belonging to the Trypanosoma cruzi genotype I. These differences include parasitaemia, in vitro infection
and virulence. The present study compares the inflammatory reactions caused by these two strains,
identified as virulent and non-virulent. Heart, skeletal muscle and large intestine of control or infected
BALB/c mice were analyzed at 1, 15, 21 and 90 days post-infection (pi). Using a polyclonal antibody
against the parasite, amastigote nests were detected only at days 15 and 21 pi. The number of nests was
higher in the animals infected with the virulent strain than with the non-virulent strain. No parasites
were detected at 1 and 90 days pi using this technique. Tissue inflammation was evaluated by hematoxylin/eosin stain and the severity was numerically score. The score of inflammation also was higher with the
virulent strain in the tissues analyzed. Besides, only the virulent strain produced sites of calcification in
the skeletal muscle, as revealed by the von Kossa stain, indicating a possible necrotic event. Using the F4/
80 antibody, the presence of macrophages in the infiltrated nests was analyzed. Again, there were a
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ABSTRACTS
higher number of infiltrated nests in heart, skeletal muscle and large intestine of mice infected with the
virulent strain than with the non-virulent strain. The proportion of macrophages present in these infiltrations, however, varied between 20 and 34%, depending on the tissue and the infecting strain. Interestingly, macrophages were not detected in heart infiltrated nests. The virulent strain also induced a higher
mRNA expression of the cytokines IL-10, IL-12, IL-4, INF-γ and TNF-α in heart and of the cytokine
TNF-α in skeletal muscle at 21 days pi, as detected by real time RT-PCR. In conclusion, the virulent
strain induces a differential inflammatory reaction with a severe damage in skeletal muscle than the nonvirulent strain in our murine model in spite of belonging to the same genotype.
363
Leishmania LPG Activates TLR2 Signaling Pathway in NK Cells. E.A. FERNANDEZ-FIGUEROA*, I.C.
CAÑEDA-GUZMÁN, N.L. SALAIZA-SUAZO, I.D. BECKER and M.M. AGUIRRE-GARCÍA, Departamento de Medicina Experimental, Facultad de Medicna, UNAM, México DF, México.
Toll-like receptors (TLRs) are key components of the innate immune system that recognize a wide range
of microbial pathogens, and represent a primary line of defense against invading pathogens. Recognition
of microbial components by TLRs trigger a cascade of cellular signals that start with the association of
MyD88 to TLR2. Downstream signaling is mediated through the interaction of MyD88 with IRAK-4,
which recruits and phosphorylates IRAK-1 that can autophosphorylate itself, recruiting TRAF6. Next,
IRAK-1 and TRAF6 dissociate from the receptor complex and interact with additional molecules, the
signalosome (IKK alpha, beta and gamma) activation phosphorilates IkB protein that culminates in the
activation of Nuclear Factor kappa B (NF-kB), which induces gene expression. The importance of TLR
signaling has been analyzed in patients with polymorphisms in genes of TLR signaling molecules. We
have shown that Leishmania major lipophosphoglycan (LPG) is a ligand for TLR2. On the other hand,
one of the cells of the innate immune response that is involved in the natural protection against leishmaniasis is the NK cell. TLR2 activation by Leishmania LPG in NK cells leads to production of IFNgamma and TNF-alpha as well as enhanced nuclear translocation of NF-kB. In the present work, we
analyzed the TLR2 pathway in NK cells stimulated with LPG. First, by Western-blot, we observed an
increased expression of MyD88, TRAF6, IRAK1, IKKs and IkB proteins, and the phosphorylation of
IKK and IkB when NK cells were stimulated with LPG. With immunoprecipitations, we detected
increased binding of proteins: TLR2-MyD88, MyD88-IRAK1, MyD88-TRAF6 and TRAF6-IRAK1.
These results show that Leishmania LPG actives NK cells through TLR2 signaling pathway. It would be
interesting to analyze this pathway in patients’ NK cells.
364
Towards the Development of an Oral Vaccine Against Cysticercosis and Taeniasis Using Transgenic
Plants. J. CERVANTES, M. HERNÁNDEZ, Immunology Department, Instituto de Investigaciones
Biomedicas, UNAM, Ciudad Universitaria, México DF, L. AGUILAR, Microbiology and Parasitology
Department, Facultad de Medicina, UNAM, Ciudad Universitaria, México DF, N. PEÑA, Facultad de
Medicina Veterinaria y Zootecnia, Ciudad Universitaria, México DF, J.L. CABRERA-PONCE, L.
HERRERA-ESTRELLA, Genetic Engineering of Plants Department, CINVESTAV, Irapuato, Gto. México,
A. GUEVARA-GARCIA, Instituto de Biotecnologia, UNAM, Cuernavaca, Mor. México, K. WILLMS,
Microbiology and Parasitology Department, Facultad de Medicina, UNAM, Ciudad Universitaria,
México DF, G. FRAGOSO and E.L. SCIUTTO*, Immunology Department, Instituto de Investigaciones
Biomedicas, UNAM, Ciudad Universitaria, México DF, México.
The disease caused by the larval stage of Taenia solium is progressively being recognized as a growing
global threat for public human health and pig husbandry that requires the development of effective
control measures. The S3Pvac anti-cysticercosis peptide vaccine based on the three synthetic peptides,
KETc1, GK1(KETc7) and KETc12, has been developed successfully and proved to be effective against
murine and porcine cysticercosis, as well as against experimental Taenia solium intestinal taeniasis.
However, the high cost of its production and the logistic difficulty inherent to needle administration
limit its widespread use. An effective oral vaccine delivery in transgenic plants could cope with both
obstacles. Thus, transgenic papaya clones expressing the S3Pvac peptides were developed and shown to
be protective when administered subcutaneously. In this study, we report the protection induced against
experimental cysticercosis and taeniasis using the S3Pvac administered orally in transgenic papaya. Oral
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ABSTRACTS
immunization using a cell suspension of transgenic embryogenic callus reduced the expected number of
cysticerci or tapeworms up to 70%. The advances obtained offer a novel and promising system of a
useful, sustainable and affordable method for the control of taeniasis/cysticercosis in the field.
365
Neurocysticercosis Pathology Associated with the Local and Systemic Immune Response. B.I. SAENZ*,
Instituto de Investigaciones Biomedicas, UNAM, A. FLEURY, Instituto Nacional de Neurologia y
Neurocirugia, México, A. CHAVARRIA, Facultad de Medicina, UNAM, G. FRAGOSO, Instituto de
Investigaciones Biomedicas, UNAM, C. MÁRQUEZ, Instituto Nacional de Neurologia y Neurocirugia,
México, J. CRISPIN, M. VARGAS, Instituto Nacional de Ciencias Medicas y de la Nutricion, México,
and E.L. SCIUTTO, Instituto de Investigaciones Biomedicas, UNAM, México.
Neurocysticercosis (NC) is a disease caused by Taenia solium when lodged in the central nervous system
and characterized by a great diversity of clinical manifestations. The immunological response is a factor
involved in this heterogeneity that has been poorly explored. Few studies have been done regarding the
characterization of the immunological response in cerebrospinal fluid (CSF) and in peripheral blood
separately, but the relation between immunological response in both compartments, associated with the
clinical and radiological profile have not been explored yet. In this study, cytokine levels (IL1β, IL4, IL5,
IL10, IL12, IL13, IFNα and TNFγ) in CSF and in supernatants of peripheral mononuclear blood cells
estimulated especifically (SN) and specific cell proliferation of 31 patients with NC characterized clinically and radiologicaly were studied. The relation between local and peripheral immune response and
their clinical, radiological and immunological status was explored. Severe NC patients, characterized by
the presence of intracranial hypertension, multiple vesicular parasites located in the subarachoid space of
the base or in ventricles and with inflammatory CSF presented increased levels of IL5 and IL10 in CSF,
increased levels of TNFγ in SN and decreased cell proliferation in peripheral blood cells specifically
stimulated. In contrast, patients with non-severe symptomatology such as those without intracranial
hypertension and colloidal and/or calcified parasites located in parenchyma presented increased levels of
IL13 in SN. We found differences in the immunologic response associated with different clinic and
radiological characteristics of disease. Cytokines that originate either systemically or within the CNS may
exert concerted action over parasites and further studies considering multiple factors related with NC
pathogeny in addition to those clinical, radiological and inflammatory explored in this study should
contribute to a better understanding of the heterogeneity of the disease and to the capability to classify
and predict patients’ clinical outcome.
366
Analysis of IgA, IgM and IgG Antibody Responses to Trichinella spiralis Adult Antigens During Infection
in the Rat. D. MARTÍNEZ-ALARCON*, Departamento de Inmunologia, E. NAVARRETE-RAMIREZ,
Departamento de Parasitologia, and M.R. SALINAS-TOBON, Departamento de Inmunologia, Escuela
Nacional de Ciencias Biologicas, Instituto Politecnico Nacional, México DF, México.
In rodents and pigs protective immunity against the Trichinella spiralis adult (AD) stage by specific
antibodies (Abs) has been described. Characterization of the Ab response to the parasite as well as of the
T. spiralis antigens (Ags) is relevant to identify useful Ags in diagnostic and protection. The goal of this
work was to analyze the kinetics of IgA, IgM and IgG production, and to identify the AD Ags recognized by these Abs. Serum samples were collected from rats infected with 2,000 muscular larvae at
different postinfection (pi) times, and were analyzed either by indirect ELISA for IgG or by amplified
ELISA for IgM and IgA detection using AD total soluble Ag. Likewise, sera were tested by Western blot
(Wb) analysis. Differences in the class specific Ab response and the recognition of AD Ags were found
during the infection; IgG response was higher than the IgM response and this, in turn, higher than that
of IgA. IgG response started from day 12, reached a maximum by day 19 and remained until day 31,
while the IgM production was observed by day 12, reached a peak by day 17 and then decreased slightly
until the end of the study. Contrastingly, the IgA response was very weak during the infection. Wb
analysis showed quantitative and qualitative variations in the recognition of AD components during the
infection. IgG Abs recognized about six proteins with molecular weights ranging from 29 to 273 kDa
from day 12 to 31 pi; proteins of 251 and 273 kDa were recognized strongly by days 14, 17 and 19 pi,
while proteins of 29, 33, 56 and 101 kDa were recognized weakly. IgM Abs bound to five proteins from
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ABSTRACTS
86 to 273 kDa; a strong recognition was observed towards AD Ags of 144, 273 and 202 kDa from days
12, 17 and 21, respectively, until the end of the study. IgA Abs showed a non-intense recognition toward
three proteins of 123, 169 and 191 kDa during the infection. The differential recognition of AD Ags by
Ab isotypes observed in this survey together with a similar study on AD Ags recognition by different
coproAb isotypes will help to identify AD Ags potentially useful for diagnosis and protection.
367
Systemic and Intestinal Antibody Response Against the Adult Stage of Trichinella spiralis. E.
NAVARRETE-RAMIREZ*, Departamento de Parasitologia, B.M. COAXILOA-MANTECON, T. BANDASÁNCHEZ, Departamento de Inmunologia, F. GOMEZ-MARTÍNEZ, Departamento de Parasitología,
and M.R. SALINAS-TOBON, Departamento de Inmunologia, Escuela Nacional de Ciencias Biologicas,
Instituto Politecnico Nacional, México DF, México.
Several studies suggest that human beings and rats develop a similar humoral immune response to the
Trichinella spiralis adult (AD) stage. In addition, the role of immunodominant AD antigens (Ags) in the
host–parasite interplay can be studied in the rat. In this context, studies on systemic and intestinal
antibody (Ab) production and somatic AD Ag characterization are scarce. Thus, the objective of this
work was to analyze the total AD Ab levels in serum samples taken from rats infected with different
muscle larva (ML) infective doses and to identify the AD Ags recognized during the infection. Kinetics
of total coproAbs also were studied. Serum samples were obtained before and after the infection at
different time intervals from rats infected with 700, 2000, 4000 or 8000 ML. Feces were collected from
rats infected with 2000 LM at the same postinfection (pi) times. Feces supernatants and sera were tested
by indirect ELISA and the latter by Western blot (Wb) using AD total soluble Ag. Slight differences
were observed in the time Abs appeared, point of maximum Ab level and Ab levels during the infection
with regard to the infective dose; Ab response was detected at day 12, reached a peak from days 14 to 19
pi and then decreased up to day 31 pi. A profile of at least 20 AD Ag with molecular weights of 30 to
273 kDa was observed. Among these, eight were the most inmunogenic (273, 251, 167, 131, 114, 92,
49, 30 kDa). However, the recognition of the highest number of AD components was observed with the
highest infective dose, except for the components of 273 and 251 kDa, which were recognized intensely
regardless of the dose. Three peaks of total coproAbs were observed by days 3, 5 and 7 pi. The early
intestinal Ab response observed in this study reveals the importance to identify specific antigens to
determine their value in diagnostic and protection.
368
Intestinal Cytokine Production Profile in Hamsters Experimentally Infected with Taenia solium Cysticerci. M. CRUZ-RIVERA*, Department of Microbiology and Parasitology, School of Medicine, UNAM,
México, G. VAUGHAN, Department of Immunology Research, Institute for Epidemiological Diagnosis
and Reference, Secretariat of Health, México, G. AVILA and A. FLISSER, Department of Microbiology
and Parasitology, School of Medicine, UNAM, México.
Taenia solium is the causal agent of two different diseases in the human being: taeniosis and cysticercosis.
Cysticercosis by T. solium is the leading cause of late-onset epilepsy in most developing countries and it
has very important public health implications due to its complex and costly treatment. On the other
hand, taeniosis is an enteric illness originated by the establishment of the adult stage of the parasite in the
host intestinal tract with a generally benign course. Because of feasibility of treatment and prevention,
taeniosis has been proposed as a target for control measures to reduce human cysticercosis by T. solium.
Studies on the host–parasite relationship have been limited for the lack of an adequate animal model that
accurately represents the manifestations observed in human infections. Our group has previously reported different taeniosis animal models, including chinchillas, gerbils and hamsters, with a wide spectrum of parasite development. In this work, we describe the cytokine profile produced on the site of
scolex anchorage in hamsters experimentally infected with T. solium cysticerci by RT-PCR. The results
might contribute to the understanding of the mechanisms used by the parasite to succeed and survive for
extended periods of time commonly observed in this parasitosis or to the mechanisms used by the host
to expel the worms.
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ABSTRACTS
369
Detection of Toxoplasma in Pork Meat by Tissue Culture, Bioassay in Mice, ELISA, Polymerase Chain
Reaction and Histopathology. M. GALVÁN-RAMÍREZ*, Departamento de Fisiología, Centro Universitario de Ciencias de la Salud, U. de G., Guadalajara, Jalisco, A.L. MADRIZ-ELISONDO, Departamento
de Ciencias Básicas, Centro Universitario de la Ciénega, U. de G., Guadalajara, Jalisco, C.P. RICOTORRES, H. LUNA-PASTÉN, Laboratorio de Patología Experimental, INP, SSA, México DF, L.R.
RODRÍGUEZ-PÉREZ, Departamento de Fisiología, Centro Universitario de Ciencias de la Salud, U. de
G., Guadalajara, Jalisco, A. RINCON-SÁNCHEZ, Departamento de Biología Molecular, Centro Universitario de Ciencias de la Salud, U. de G., Guadalajara, Jal., R.A. FRANCO TOPETE, Nuevo Hospital
Civil de Guadalajara, Guadalajara, Jalisco, and D. CORREA, Laboratorio de Patología Experimental,
INP, SSA, México DF, México.
Background: Toxoplasmosis is an infection caused by Toxoplasma gondii, an obligate intracellular parasite.
The transmission usually has been attributed to ingestion of undercooked or raw meat. Toxoplasmosis is
one of the most prevalent parasitic infections in humans and animals worldwide.Toxoplasmosis is a
potentially fatal disease in the development of human fetuses, immunocompromised patients (e.g., AIDS
and transplant patients) and can cause severe ocular disease in healthy individuals. The average prevalence
in humans in México is 50%, but the frecuency of T. gondii in pork, the main meat consumed, is unknown. Objective: To determine the frecuency of T. gondii in pork meat obtained from butcher shops
and to determine the genotypes of strains found. Methods: Forty-eight samples of pork meat from
butcher shops were analyzed, 24 from the city and 24 from rural areas. The B1 gene was attempted to be
amplified from 50 mg of each meat by hemi-nested PCR, while 50 g were homogenized individually in
an acidic pepsin solution and bioassayed in mice, which were bled at days 0, 7, 14, 28 and 45 days to
determine anti-Toxoplasma antibodies by indirect ELISA. Brain, heart, muscle and lungs of the mice were
stained with hematoxilin and eosin (HE). Isoltation also was attempted in human fibroblast cell cultures.
Results: The PCR was negative for all samples, and no tachyzoites or tissue cyst were found in hispopathology. Living parasites could not be isoleted either in vivo or in vitro, but IgG and IgM antibodies
against T. gondii were detected by ELISA in 1/48 (2.08%) of them. A similar frecuency of T. gondii in
pork has been found in other countries. The antobody kinetics and the lack of clinical problems in
positive mouse suggest that a non-virulent strain could be present in the pork meat inoculated.
370
Human Cystic Echinococcosis in Slovenia. J. LOGAR*, B. SOBA, Institute of Microbiology and Immunology, Medical Faculty, University of Ljubljana, Ljubljana, Slovenia, and T. LEJKO-ZUPANC, Infectious
Diseases and Febrile illnesses, University Medical Centre Ljubljana, Ljubljana, Slovenia.
Cystic echinococcosis (CE) is caused by the larva of tapeworm Echinococcus granulosus. Dogs and other
canids are the primary definitive hosts for this parasite. By ingesting the tapeworm eggs excreted by the
feces of these animals, the larval stage of CE may develop in livestock and sometimes in humans as
intermediate hosts, usually in the liver or lungs. The aim of this study was to examine serologically
whether some of the patients suspected of CE had been infected by the larva of Echinococcus granulosus.
From January 2002 to the end of December 2006, 1,323 patients of both sexes from different parts of
Slovenia were screened serologically by indirect haemagglutination test (IHA, Cellognost–Echinococcosis, Dade Behring, Germany). IHA positive sera with low, mid-range and high titers were retested by
Western blot (WB, LDBIO Diagnostic, Lyon, France). Of the 127 IHA positive sera, 34 were proved to
be positive for CE by WB; these sera included the band at 7 kDa only or the band at 7 kDa and at least
diffuse band at 16 to 18 kDa and usually also the band at 26 to 28 kDa. Thirty-two of 34 patients whose
sera were CE positive had cysts in the liver and two in the lungs. No significant differences were found
between the patients in regard to their sex. The observed incidence of CE (1.7 per 105 inhabitants) and
mean annual incidence (0.34 per 105 inhabitants) suggest that clinicians and public health authorities,
especially from the southern to north-eastern parts of Slovenia where the most patients with CE come
from, should pay more attention to this disease in the future.
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ABSTRACTS
371
A Host–Parasite List of the Advanced Third-stage Larva of Gnathostoma binucleatum Almeyda-Artigas,
1991 (Nematoda: Spirurida) from Freshwater and Estuarine Fishes and Their Potential Role in Larval
Transmission to Humans in México. R.J. ALMEYDA-ARTIGAS* and J. GASPAR-NAVARRO, Laboratorio
de Sanidad Acuícola y Parasitología Molecular (LSAyPM), Departamento “El Hombre y su Ambiente,”
Universidad Autónoma Metropolitana–Xochimilco, México DF, México.
An annotated host–parasite list of the advanced third-stage larva (AdvL3) of Gnathostoma binucleatum
Almeyda-Artigas, 1991 (Nematoda: Spirurida) from Mexican fishes is presented. The list contains the
AdvL 3 found in freshwater and estuarine fishes that act as second intermediate or paratenic hosts
inhabiting waters that pour their content into both the Gulf of México and the Pacific Ocean. The
records came from the LSAyPM Helminth Collection database (1989–2006) and from specialized
literature (1989–2005). Our results indicate that at least 29 fish species were positive to the infection,
grouped in 11 families of six orders, distributed along eight Mexican states (five with basins related to
the Gulf of México and three related to the Pacific Ocean). The greatest values of prevalence and mean
intensity were yielded for the following species: (i) Gulf of México: Gobiomorus dormitor (Perciformes:
Eleotridae) (present in four of five states) and Petenia splendida (Perciformes: Cichlidae) (3/5) and (ii)
Pacific Ocean: Ariopsis guatemalensis (Siluriformes: Ariidae) (3/3) and Gobiomorus maculatus, Eleotris
picta, and Dormitator latifrons (Peciformes: Eleotridae) (2/3). Finally, it is worthwhile to highlight the
role of the so-called “mojarras tilapia” Oreochromis spp. in larval transmission to humans, despite the low
values yielded for the quantitative descriptors of parasite populations that were tested, due to its ample
distribution in both natural and artificial national water bodies and to its usage in the preparation of
poorly cooked meals (e.g., “cebiche”). Thus, Trichiurus lepturus and Scomberomorus maculatus (Perciformes: Scombridae) (Gulf of México) and S. sierra (Pacific Ocean) should be considered as having a
potential role in larval transmission, despite the negative values yielded for AdvL3 of G. binucleatum.
372
Evaluation of a Salivary Antibody Immunoassay for Detection of Cryptosporidium Infections. S.M.
HUNT*, Oak Ridge Institute for Science and Education, Oak Ridge TN, G.S. FOUT, National Exposure
Research Laboratory, U.S. EPA, Cincinnati OH, M.M. ROTHERMICH, National Center for Environmental Assessment, U.S. EPA, Cincinnati OH, T. WADE, National Health and Environmental Effects Research Laboratory, U.S. EPA, Research Triangle Park NC, and A. EGOROV, National Center for Environmental Assessment, U.S. EPA, Cincinnati OH, USA.
The U.S. EPA has implemented a study using salivary antibody responses to evaluate the impact of
environmental regulations on public health. The objectives of this ongoing study are to develop and
validate the use of salivary antibodies to Cryptosporidium and several other waterborne pathogens for
infection surveillance, and to characterize the incidence of infections in a community that has been served
by an outdated water treatment plant and contaminated source water. Raw and treated water samples
have been analyzed for Cryptosporidium and Giardia using U.S. EPA Method 1623. The results demonstrated a substantial variability in the parasite removal efficiency of the plant. Monthly saliva samples,
data on tap water consumption, and histories of acute gastrointestinal illness have been collected from
398 families. A total of 5,160 monthly saliva samples were collected from 1,398 individuals. The saliva
samples are analyzed for total and pathogen-specific IgA, IgG, and IgM responses using the Luminex
multiplex microbead immunoassay system in which different sets of color-coded microbeads are coupled
with recombinant 27 kDa Cryptosporidium protein, proteins of common enteric viruses, or anti-human
immunoglobulin antibodies. An increase in pathogen-specific antibody response between consecutive
samples (adjusted for total antibody response) indicates infection. The multiplex Luminex assay was
pilot-tested using samples from 15 U.S. EPA volunteers to assess inter- and intra-assay, within day, dayto-day and week-to-week variability of salivary antibody responses. The pilot study results indicated that
the Luminex system can be used to measure salivary antibody responses. The laboratory analyses of the
saliva samples from the community study are now in progress.
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ABSTRACTS
373
Present and Potential Distribution of Gnathostoma spp. (Nematoda: Gnathostomatidae) in México. Y.
PÉREZ-ALVAREZ, L. GARCÍA-PRIETO, D. OSORIO-SARABIA, V. LEÓN-RÉGAGNON* and E.
MARTÍNEZ-MEYER, Instituto de Biología, UNAM, Ciudad Universitaria, México DF, México.
Gnathostomosis, caused by nematodes of the genus Gnathostoma, is an emerging infectious disease in
México. Currently, more than 8,000 human cases have been recorded, mainly in Nayarit state. Three
species of this genus have been recorded in México parasitizing wild vertebrates: Gnathostoma binucleatum, Gnathostoma lamothei, and Gnathostoma turgidum. However, the present distribution of these
species in their vertebrate hosts is far from being well known, mainly because most records are scattered
and published in local sources. The objective of this work is to compile such records to generate a current
distribution map of this genus in México, and, based on this information, model the potential distribution of these nematodes. A potential distribution map was generated using two geographic information
systems (GIS): ArcView 3.2, and GARP (Genetic Algorithm for Rule-set Prediction), considering 14
environmental variables. From actual records, we found that the most widely distributed species is G.
binucleatum, found in 10 states of Mexican Republic, parasitizing 60 host species (27 fishes, one amphibian, eight reptiles, 19 birds and five mammals); distribution of G. turgidum and G. lamothei is comparatively restricted: seven and two states, and six and one host species, respectively. In accordance with the
consensus potential distribution map of Gnathostoma spp, potential regions of infection are concentrated
on both coasts of México; in the Pacific coast, the modeled ecological niche extends from Nayarit to
Oaxaca, while on the Atlantic coast, it is concentrated in the central region of Veracruz and north of
Oaxaca. On both coasts, the population potentially exposed to this infection ascends to five million,
including important cities as Acapulco, Guerrero, and Tepic, Nayarit. The use of this information can
constitute an important preventive tool in zones of risk.
374
Snook Parasites and Their Potential Effect in Public Health. L. GARCIA-MAGAÑA*, S. LÓPEZ-JIMÉNEZ
and R. GAMAS-TRIANO, División Académica de Ciencias Biológicas, UJAT, Villahermosa, Tabasco,
México.
The representatives of the Centropomus gender, better known as “snooks,” are a highly sought-after and
diverse species in great demand in domestic and international markets. In the state of Tabasco, four
species are registered, with Centropomus undecimalis (white snook) being the most captured, followed by
C. parallelus (“chucumite”). They are fished for in coastal lagoons, estuaries and tidelands with diverse
fishing arts. A study of their parasitofauna was carried out since a determination of possible species has
implications in public health, since the commercialization of the snook is mainly foreign, with 80%
distributed in México City and 20% staying in the state. The examined organisms were taken from the
commercial captures. They registered five species of parasites for C. parallelus and 10 species for C.
undecimalis. Besides the reported species of parasites, it is important to point out the presence of larvae
of Contracaecum sp., Gnathostoma sp. and of Pentastomidos, with prevalences of 73%, 10% and 36%,
respectively, for C. undecimalis. The larvae of Contracaecum sp. are very frequent in fish of sweet water of
the state of Tabasco, but they always show up housed in the mesentery; in these registrations, 95% of the
larvae were in the stomach at the level of the submucosa, which shows its possible migration capacity.
Anisakid larvae and Gnathostoma are reported as having no effect on humans, and the pentastomidos
nymphs have been reported in humans in the African continent.
375
Rate of Chagas Disease in the State of Queretaro for Populations Under 18 Years of Age. P.M.S.
SALAZAR-SCHETTINO*, G.S. GARCÍA-DE LA TORRE, M. CABRERA-BRAVO, M.I. BUCIO-TORRES,
G.E. ROJAS-WASTAVINO, A.L. RUIZ-HERNÁNDEZ, Y. GUEVARA-GÓMEZ, M.O. VENCES-BLANCO
and E. TORRES-GUTIÉRREZ, Departamento de Microbiología y Parasitología, Facultad de Medicina,
UNAM, México DF, México.
The objective was to describe the rate of American Trypanosomiasis for people under 18 years of age in
Queretaro and recognize this group as an epidemiological indicator in active vectorial transmission of the
disease. A transversal study was carried out in which the size of the sample was assigned proportionally
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ABSTRACTS
to each health jurisdiction of the state. The sample studied was random, and excluded people who had
lived less than a year in that community and had never been transfused. Sociodemographic information
was collected, as well as the type and quality of the houses, and a serologic study by ELISA in eluid,
ELISA in serum and IIF in serum was done. A total of 828 minors were studied in which 42% were
seven years old or younger; 50.6% were males and the rest females. The studies on 11-year-olds and
older were: 41% had completed primary school, 47.4% were still studying, 32.1% admitted to recognizing the vector, 76.3% lived with domestic animals, 40.5% slept within overcrowding, and 74.5%
periodically sprayed insecticide. The houses were classified as follows: 1.4% as “Choza” or “Hut,” 17.9%
as “Jacal,” and 80.7% as a proper “House.” The rate of Chagas Disease was 2.4% with a total of 20
confirmed diagnosed cases, of which 60% were patients seven years old or less. Certainly this reflects an
active transmission, therefore the necessity and importance of intensifying actions directed to stop
transmission and control the disease.
376
Importance of Clinical Screening in the Infection for Trypanosoma cruzi in Candidates to Blood Donors
and Risk Associated Background. A.L. RUIZ-HERNÁNDEZ*, Lab. de Biología de Parásitos, Depto. de
Microbiología y Parasitología, Fac. de Medicina, UNAM, México DF, J. ROJO-MEDINA, Banco de
Sangre, Hospital General de México OD, México DF, M.I. BUCIO-TORRES, M. CABRERA-BRAVO,
Lab. de Biología de Parásitos, Depto. de Microbiología y Parasitología, Fac. de Medicina, UNAM,
México DF, G. ESTRADA-GARCÍA, Banco de Sangre. Hospital General de México OD, México DF,
P.M.S. SALAZAR-SCHETTINO, Lab. de Biología de Parásitos, Depto. de Microbiología y Parasitología,
Fac. de Medicina, UNAM, México DF, G.E. ROJAS-WASTAVINO, Lab. de Biología de Parásitos, Depto.
de Microbiología y Parasitología, Fac. de Medicina, UNAM, México DF, L. RUÍZ-GONZÁLEZ, M.
GUTIÉRREZ-QUIRÓZ, Lab. de Inmunoparasitología, Depto. de Microbiología y Parasitología, Fac. de
Medicina, UNAM, México DF, and Y. GUEVARA-GOMEZ, Lab. de Biología de Parásitos, Depto. de
Microbiología y Parasitología, Fac. de Medicina, UNAM, México DF, México.
A guideline for Mexican blood banks is surveillance for Chagas disease; however, it is not obligatory in
all banks and is carried out as isolated actions that, in some cases, ends with the use of an epidemiological
questionnaire. In the case of an affirmative answer and without further tests, these blood donor candidates are rejected because they constitute a “possible infection source.” By means of a clinical ad hoc
questionnaire, tests for serological confirmation, and a letter of informed consent, we studied 58 blood
donor candidates in the Blood Bank of the “Hospital General de México” (2005–2006). These individuals had been rejected as donors, because risk factors for Chagas disease were detected (knowing the
vector; having been bitten by triatomines; donation or reception of blood; living in endemic areas).
Blood samples obtained by venous puncture were dotted on paper filter; seroreactivity was confirmed
with ELISA and IIF. The study revealed 53 seronegative individuals (91.4%) for T. cruzi and five males
(8.6%) seropositive to both tests; two of them had been blood donors, one was bitten by the vector, and
three cases were natives from Veracruz, Oaxaca, and Baja California. Our results indicated that blood
banks and academic institutions should not rely only on the initial clinical screening for Chagas, but
should perform a second serological confirmation assay to detect cases, in which they should obtain
information on the transfusional follow up and epidemiological data. Important links between institutional and health sector must be established for society’s benefit.
377
Characterization of Intermediate Form Developmental Stages During Amastigogenesis of Trypanosoma
cruzi. L.A. HERNÁNDEZ-OSORIO*, Facultad de Ciencias Quimicas, Universidad Autónoma Benito
Juarez de Oaxaca, Oaxaca, and R.G. MANNING-CELA, Departamento de Biomedicina Molecular,
CINVESTAV-IPN, México DF, México.
Trypanosoma cruzi undergoes a biphasic life cycle of four alternate developmental stages that survive a
wide range of environmental conditions, experiencing morphological and physiological complex changes.
The amastigogenesis happens naturally in the host mammalian cells when the trypomastigotes invade the
target cell through a parasitophorous vacuole, where they are exposed to acid pH as an essential step for
its differentiation before they multiply freely in the cytosol. Although the differentiation process is crucial
for the parasite’s survival, to continue their life cycle and to propagate the infection, the molecular
220
ABSTRACTS
mechanisms involved are unknown. It has been reported that the differentiation of the developmental
stages is not a one-step event, but instead continuous morphological changes appear to be involved with
the appearance of several intermediate forms (IFs) that have not been characterized so far. Therefore, in
the present study, we obtained and characterized the different IFs resulting from the differentiation of
trypomastigotes to amastigotes, and evaluated its movement and morphological changes, the expression
of specific developmental markers, resistance capacity to the complement and kinetic of displacement and
morphology of nucleus and kinetoplast. In the in vitro conditions used, the IFs showed a highly synchronous genotypic and phenotypic gradual transformation, with a progressive decrease of the parasite,
undulating membrane and flagellum size as well as its movement capacity, concomitant with the gradual
acquisition of the specific surface antigen Ssp4 of amastigotes. In addition, there was a nucleus remodeling and the kinetoplast displaced from the posterior to the anterior side of the parasite. Finally, the
trypomastigotes, amastigotes and IFs were resistant to the complement as it was reported previously for
trypomastigotes and amastigotes. These results are the beginning for future analyses of the differential
expression of intermediate forms in order to detect the possible molecules involved in the detonation and
modulation of the differentiation process.
378
Can the Analysis of the Helminth Prevalence in Dogs Be an Indicator of the Earth Warming? P.M.
ACEVEDO-RAMÍREZ *, A. RODRÍGUEZ-CABALLERO, R.I. LUNA-OCHOA, G.E. PERALTA-ABARCA,
M. PONCE-MACOTELA and M.N. MARTÍNEZ-GORDILLO, Parasitología Experimental, Instituto
Nacional de Pediatría, México DF, México.
Domesticated dogs (Canis familiaris L.) are a source of zoonotic parasites, and the most prevalent
helminthes are Dipylidium caninum, Ancylostoma caninum and Toxocara canis. It is remarkable that
infective stages of these parasites depend of environmental temperatures. Unfortunately, there are few
studies aimed at learning the frequency and fluctuation of these commonest helminthes. In this work, we
compared the prevalence of the named helminthes in dogs less than six months old, euthanazied at the
Control Canine Centre “Culhuacan,” for two periods (March 2001–October 2002 and October 2005–
July 2006). Harvested small intestines were carried to the laboratory in wide-mouth bottles; then we
made a longitudinal cut, and all the macroscopic roundworms and tapeworms were picked up individually with forceps or a paint brush, washed with buffered saline phosphates pH 7.0 warmed to 37°C, fixed
with 5% buffered formaldehyde and identified. In the first sampling, we analyzed 141 guts and found
29% of D. caninum, 38% A. caninum and 63.5% T. canis. During the second period, we studied 157
small intestines and found 32% of D. caninum 56.05% A. caninum and 84.1% T. canis. In the survey,
there were other, less frequent helminthes such as Taenia, Toxascaris, Hymenolepis, etc. Our data are
important because we are witness an increase in the prevalence of A. caninum in dogs less than six
months old, perhaps as a direct result of the Earth warming. The increase in the prevalence of these
parasites is evidence of global warming.
379
Prevalence of Swine Cysticercosis in Three Rural Communities from Southern México. F. CENAGUILAR*, Departamento de Investigación, CBTA Xmatkuil, Mérida, México, R.D. RODRÍGUEZCANUL, J.A. PÉREZ-VEGA, Laboratorio de Inmunologia y Biología Molecular, CINVESTAV IPN, Unidad
Mérida, Mérida, Yucatán, México, J.L. DOMINGUEZ-ALPIZAR, FMVZ-UADY, Xmatkuil, Mérida,
México, J.C. ALLAN, Pfizer Animal Health. Pfizer Ltd., Sandwich, Kent, U.K., and P.S. CRAIG, Cestode
Zoonoses Research Group, University of Salford, Salford, U.K.
Swine cysticercosis produced by the larval stage of Taenia solium is highly prevalent in México. Its
transmission has been associated to low sanitary facilities, poor hygiene and traditional methods of
backyard farming, allowing pigs to roam freely. In this study, an immunoblot and the tongue palpation
(TP) method were used to assess prevalence and to evaluate risk factors in three rural communities from
July 2002 to November 2003. After informed consent, a blood was collected from the jugular vein of
pigs. Prevalence and seroprevalence were estimated as the number of infected and/or exposed individuals
from the total analyzed. Risk factors were estimated by γ2 using Odd Ratios in Epi Info 6.0. A total of
231 pigs from 1–48 months old were recorded in the three communities: 198 free-range pigs, 18 tied
pigs and 15 confined pigs. In Kochol (20º37′N, 90º10′W), seroprevalence of porcine cysticercosis was
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ABSTRACTS
of 12% (47/400) and 5.5% (22/400) by TP. In Santo Domingo (20º37′N, 90º11′W), seroprevalence
and prevalence was 2.7% (2/73) by immunoblot and TP, respectively. In San Rafael (20º36′N, 90º9′W),
it was 0.5% (1/183) by immunoblot and TP, respectively. There were no differences by age groups and
no differences between sows and boars. The major antibody exposition was observed in the free-range
pigs group. Having easy access to areas designated as toilets (P = 0.001), traditional pig husbandry
practices promote perpetuation of the life cycle of T. solium in rural communities.
380
A Seasonal Survey of Human Intestinal Parasites in Patients in the Rocky Mountain Region of Colorado,
USA. A. NEILL, A. HODD and C. CHURCH*, Biology Department, Metropolitan State College, Denver
CO, USA.
To evaluate the seasonal prevalence of human intestinal parasites in the Rocky Mountain Region of
Colorado, USA, fecal samples were obtained from patients receiving diagnostic tests due to gastrointestinal symptoms during the summer of 2006 and the winter and spring of 2007. Parasite identification in
positive samples was confirmed using wet mount and trichrome staining techniques. Seventy-eight
patients, which represented 7% of those surveyed, tested positive for at least one species of intestinal
parasite in the summer sample. Forty-eight (7% of surveyed) patients tested positive for at least one
species of intestinal parasite in the winter sample. Blastocystis hominis was the most prevalent species,
followed by Giardia lamblia. Approximately one-fourth of the parasite occurrences were multiple infections involving fecal–orally transmitted species, suggesting a possible fecal–oral transmission for Blastocystis hominis. Entamoeba species were more likely to co-occur than independently occur. Other species
detected in this survey were Diphyllobothrium latum and Iodamoeba butschlii.
381
Malacological Fauna of Accompaniment of Fossaría humilis and F. bulimoides in Two Sites of México. I.
CRUZ-MENDOZA*, Departamento of Parasitology Medicine, Faculty Veterinary and Zootecnia
UNAM, University City DF, M.T. QUINTERO-MARTÍNEZ, Departamento of Parasitology, Medicine
Faculty Veterinary and Zootecnia UNAM, University City, México DF, and E. NARANJO-GARCÍA,
Zoology Department, Instituto Nacional de Biología UNAM, México.
The objective of the present work is to communicate which family and genus of snails from different
places where it has been of the Lymnaea sort, since they have been collected in different zones and these
last ones are intermediate hosts of Fasciola hepatica.The material consisted of the field snails collected in
two different regions in “Tulancingo Hidalgo” and “Chapa de Mota” Estado de México. Samples were
taken, the specimens in different biotopes, the snails were transported in plastic bags with earth and
water, according to the habitat of the snails; the bags were identified with the number of biotope and
characteristics of the collection place for transportation to the Department of Parasitology to the Medicine Veterinary Zootecny Faculty. In the laboratory, the snails were separated and were classified according to the morphologic external characteristics, then were placed in Petri dishes, and observed under the
estereoscopic microscope to determine their Family and genus using the generic key Burch 1987. In
Tulancingo Hidalgo, obtained from five biotopes were the following: 5,490 snails of 1,673 (30.4%) of
Fossaria were collected humilis, the snails associate obtained two terrestrial species Succinea sp. 3,083
(55.9%) and Helix aspersa 91 (1.6%) and two dulceacuicolas Physa cubensis 297 (5.2) and Planorbella
(Pierosoma trivolvis) 346 (6.3%). In Plate of Speck, they were identified in biotopo 1 and 2 Fossaria
humilis 3,372 (83%) and F. bulimoides was collected 670 (17%), of the snails accompaniment were
collected in biotope 1, 42 Physa sp, 18 Succinea sp., eight Planorbella (Pierosoma trivolvis), 35 Helix
aspersa and three Physa cubensis. In biotopo 2, siingle 29 Succinea sp. was 17 Helix aspersa and eight Physa
cubensis, and in biotopo 3, 125 Succinea sp., three Physa cubensis, 12 Helix aspersa and other 68 snails
non-identified. The importance of this communication is that it is necessary to study this type of malacology fauna. For in the future to implement similar studies which it has taken control of Lymnaea
having like objective to know if they can act like intermediate hosts for Fasciola hepática or for other
parasites.
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ABSTRACTS
382
Seroepidemiology of Giardiasis in México. R. CEDILLO-RIVERA*, Y. LEAL-HERRERA, Unidad de
Investigación Médica, Unidad Médica de Alta Especialidad, IMSS, Mérida, L. YÉPEZ-MULIA, O.
MUÑOZ, Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, IMSS, México
DF, and G.M. ORTEGA-PIERRES, Departamento de Genética y Biología Molecular, CINVESTAV,
México DF, México.
Objectives: To determine the prevalence of antibodies against Giardia lamblia and to investigate risk
factors for infection in Mexican individuals. Methods: the prevalence of antibodies against G. lamblia in
México was studied by enzyme liked immunosorbent assay (ELISA). The master-sampling frame from
the National Serologic Survey of Health Minister was calculated to represent all the geographic and
development areas in the country and included socioeconomic and demographic data for each person
surveyed. The antigen was a total extract from trophozoites of an axenic culture of G. lamblia strain
IMSS-1090-1, obtained from an asymptomatic individual with a chronic infection. ELISA was standardized by employing sera samples from patients with giardiasis and healthy volunteers. Results: The
seroprevalence determined was high (52.6%): 1,914 of the 3,642 tested sera were positive for IgGGiardia. This seropositivity is age-specific: in adolescents, the risk of acquisition of infection was three
times more than in children (OR 3.31, p = 0.0002); five times more in adults between 21and 30 years
of age (OR 5.09, p < 0.0000), and in adults older than 40 years, the risk of infection increases eight
times (OR 8.36, p < 0.0000). G. lamblia infection was associated with the male gender (OR 1.40, p <
0.0000). There was no association of seropositivity with socioeconomic variables and the level of development of the four different regions of the country. In conclusion, the prevalence of antibodies against G.
lamblia in México is high, indicating that giardiasis is endemic in the country. Factors associated with the
infection are age and gender.
383
Echinococcus sp. in Translocated Elk in the Great Smoky Mountains National Park (GSMNP): A Reemerging Disease? C. CROSS, E.C. RAMSAY, S. KANIA, A. CHAPMAN and S. PATTON*, College of
Veterinary Medicine, University of Tennessee, Knoxville TN, USA.
In 2000, the Tennessee Wildlife Resources Agency (TWRA) and the Rocky Mountain Elk Foundation
began a restoration project to bring elk back into the southern Appalachian land they once inhabited.
Over the next three years, elk were imported from Land Between the Lakes in Kentucky and Elk Island
in Alberta, Canada. To date, five of the reintroduced elk have been diagnosed at necropsy with pulmonary Echinococcus granulosus cysts. All necropsies were performed at the University of Tennessee College
of Veterinary Medicine. All of the diagnosed elk originated/lived at Elk Island National Park before
importation to Kentucky or Tennessee. of the five definitive cases, three of the elk were found in Tennessee and the remaining two were found within the GSMNP or its boundary in North Carolina. A sixth elk
from GSMNP had a suspicious region of fibrosis and inflammation within the lung; however, E. granulosus could not be confirmed grossly or histologically. The three elk found in Tennessee had two pulmonary cysts each. One elk from the GSMNP had four pulmonary cysts, and the second from GSMNP had
six cysts. All confirmed cases were in adult females; the elk with a suspicious lesion was an adult male. In
all cases, the pulmonary echinococcosis was considered an incidental finding. PCR of a cyst confirmed
that the elk were infected with the sylvatic strain of E. granulosus previously described from Canadian elk.
To date, there is no evidence of transmission to wild canidae in Tennessee.
384
Sociocultural and Health Practices Associated with Taenia solium Transmission. S. GARCÍACERECEDO* and L. VARGAS-PARADA, Unidad de Periodismo Científico, Dirección General de
Divulgación de la Ciencia, UNAM, México DF, México.
Sociocultural and health practices associated with Taenia solium transmission have been investigated in a
rural community where the risk factors associated with the prevalence of TC are present (deficient
sanitary infrastructure and pig-raising practices that results in pigs access to human excrement, ineffective
inspection of pig meat, etc.). The community is located in the state of Michoacán, in the western part of
the Mexican territory, and is inhabited mainly by native Indians: the Purépecha. Local authorities are
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ABSTRACTS
elected in accordance to “uses and practices of the indigenous people.” Diet, practices and preferences in
their choice of food, especially of pork meat and pork-derived products, and their relationship with
seasons and festivities were analysed. Exploratory and in-depth interviews with key members of the
community were transcribed or audiotaped with the consent of the informants. Whenever possible, a
photographic or video record was taken. Interviews were completed with participative and non-participative observations. We have been able to identify practices associated to swine breeding, purchase and sale,
routes of commercialization, slaughter and use of pork meat to prepare traditional meals. These practices
are closely related to Purépecha traditional festivities. Depending on festivities, the numbers of pigs in
the community rises or decreases, as well as pork meat that is consumed. The highest peak of pig breeding and consumption occurs during December to February (Christmas and Candelaria Festivities), while
the lowest occurs during the months of March and April due to Easter Festivities. A second peak of
breeding and consumption occurs in September for the Nativity Festivity (when locals praise the Virgin
of Nativity, the patron of the town). Another interesting observation are the relationships and alliances
that occur between members of a family and that are used as a way of exchanging animals as well as the
transmission of knowledge, practices and preferences associated to swine breeding, slaughter and food
preparation. (Project supported by Fondo Sectorial en Salud CONACYT 2004-C01-086.)
385
Characterization of Intermediate Form Development Stages During Amastigogenesis of Trypanosoma
cruzi. L.A. HERNÁNDEZ-OSORIO*, Biomedicine Molecular Department, CINVESTAV, México DF, S.
MARTÍNEZ-CALVILLO, UBIMED, UNAM, and R.G. MANNING-CELA, Biomedicine Molecular Department, CINVESTAV, México DF, México.
Trypanosoma cruzi undergoes a biphasic life cycle in which alternate four developmental stages that
survive a wide range of environmental conditions, experiencing morphological and physiological complex changes. The (amastigogenesis) naturally happens in the host mammalian cells, when the trypomastigotes invade the target cell through a parasitophorous vacuole, where they are exposed to acid pH
as an essential step for its differentiation before they multiply freely in the cytosol. Although the differentiation process is crucial for the parasite survive, to continue their life cycle and to propagate the infection, the molecular mechanisms involved are unknown. It has been reported that the differentiation of
the developmental stages is not a one-step event; instead, a continuous morphological changes appears to
be involved with the appearance of several intermediate forms (IFs) that have not been characterized so
far. Therefore, in the present study, we obtained and characterized the different IFs resulting from the
differentiation of trypomastigotes to amastigotes, and evaluated its movement and morphological
changes, expression of specific developmental markers, resistance capacity to the complement and kinetic
of displacement and morphology of nucleus and kinetoplast. In the in vitro conditions used, the IFs
showed a highly synchronous genotypic and phenotypic gradual transformation, with a progressive
decrease of the parasite, undulating membrane and flagellum size as well as its movement capacity,
concomitant with the gradual acquisition of the specific surface antigen Ssp4 of amastigotes. In addition,
there was a nucleus remodeling and the kinetoplast displaced from the posterior to the anterior side of
the parasite. Finally, the trypomastigotes, amastigotes and IFs were resistant to the complement, as it was
reported before for trypomastigotes and amastigotes.
386
Serological Evidence of Borrelia burgdorferi in Dogs of the Urban Area of Mexicali, Baja California,
México. L. TINOCO-GRACIA*, Instituto de Investigaciones en Ciencias Veterinarias, Universidad
Autónoma de Baja California, H. QUIROZ-ROMERO, M.T. QUINTERO-MARTÍNEZ, Facultad de
Medicina Veterinaria y Zootecnia, UNAM, T.B. RENTERÍA-EVANGELISTA, A. BARRERAS-SERRANO, G.
LÓPEZ-VALENCIA, S. HORI-OSHIMA, A.R. TAMAYO-SOSA, A.P. HARO-ALVAREZ, Instituto de
Investigaciones en Ciencias Veterinarias, Universidad Autónoma de Baja California, México, M.
MORO and J. VINASCO, College of Veterinary Medicine, Kansas State University, Manhattan KS, USA.
Lyme desease is a worldwide zoonotic disease caused by the espirochete B. burgdorferi transmitted by tick
bite, primarily Ixodes scapularis and I. pacificus. It is characterized by polisistemic disorders and in some
cases death. In México, B. burdorferi have been reported in dogs. In Monterrey Nuevo Leon, a seroprevalence of 16% was observed in dogs (160/850) and also in the same city molecular evidence was found
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ABSTRACTS
in dog synovial fluid. Moreover, a preliminary study performed in 2003 in Mexicali Baja, California
showed a prevalence of 7.4% (7/94) in dogs infested only by the tick Rhipicephalus sanguineus. The aim
of this study was to estimate the seroprevalence of B. burgdorferi in dogs attended at private veterinary
clinics for any circumstance in the city of Mexicali, from February 2005 to December 2006. From a total
of 98 private clinics present in Mexicali, 39 (40%) accepted to participate. A sample of 384 dogs was
selected randomly and their sera analized by the kit Borrelia burgdorferi ELISA® Helica Biosystems Inc.,
that guarantees 96% sensibility and 95% specifity. The optical density (OD) was calculated at 450 nm:
OD < 0.3 were considered negative and OD ≥ 0.3 as positive, according to the manufacturer. An
adjusted prevalence of 6% (95% CI 2.9–7.9%) was obtained using the Rogan-Gladen estimator. The
seroprevalence obtained in this study was lower compared to that in Monterrey (16%) and Sao Paulo,
Brasil (17%), where the principal vector was Ixodes scapularis. This study confirms, however, the existence of B. burgdorferi in dogs in an area where R. sanguineus is the only tick that has been identified.
Although R. sanguineus has not been considered an important vector for B. burgdoreri, we are searching
for molecular evidence of B. burgdorferi in dogs and ticks and determine the transmission mechanism.
387
Seroprevalence and Detection of Ehrlichia in Dogs from Veterinary Clinics in Mexicali (México)—
Preliminary Results. A.P. HARO-ALVAREZ, L. TINOCO-GRACIA*, G. LÓPEZ-VALENCIA, T.R.
RENTERÍA-EVANGELISTA, S. HORI-OSHIMA, G.E. MEDINA-BASULTO and A. BARRERAS-SERRANO,
Instituto de Investigaciones en Ciencias Veterinarias, Universidad Autónoma de Baja California,
México.
Canine Monocytic Ehrlichiosis is a zoonotic disease of worldwide distribution, which is caused by
obligate intracellular gram-negative proteobacteria of Ehrlichia genera that infect monocytes, Ehrlichia
canis. The principal vector is the brown dog tick, Rhiphicephalus sanguineus. Inside their own genera, E.
canis is considered the most common in dogs. The infection results in a wide range of clinical manifestations including death. The objective of this study was to estimate the seroprevalence of E. canis as well as
to detect the species of Ehrlichia in dogs examined at veterinary clinics in Mexicali (México). A total of
384 dog blood samples were collected randomly from 39 veterinary clinics in Mexicali between February
2005 and December 2006. The number of the veterinary clinics participated voluntarily in this study
corresponds to approximately 40% (39/98) of the all clinics in the city. All serum samples were analyzed
using the kit Ehrlichia canis ELISA® Helica Biosystem, Inc. The apparent seroprevalence obtained were
21.6% (83/384), (CI 95%: 17.3–25.8). Although the detailed molecular identification of the species of
Ehrlichia by PCR is under way, we have confirmed the presence of E. canis DNA in dogs. This is the first
large-scale survey of the seroprevalence in a city of U.S.–Mexican border. Further studies are required to
investigate the possible risk factors for the transmission of this disease.
388
Serological Reactivity to Trypanosoma cruzi in Three Communities of Michoacán, México, with
Samples of Blood in Filter Paper with HgI and IFI. M. GUTIÉRREZ-QUIRÓZ*, S. ALVARADO, L. RUIZ,
A. RUIZ, G. ROJAS and Y. GARCÍA, Departamento de Microbiología y Parasitología. Facultad de
Medicina, UNAM, México.
Little is known about T. cruzi human infection, although in some towns there are present ecological
conditions and transmitters, which contributes to the development of the T. cruzi biological cycle. Three
communities were studied: Uspero, Chuquiapan an Rancho seco. The study group was divided into six
groups corresponding to individuals varying from 1 to 70 years old. Five hundred twenty-three blood
samples were obtained by digital puncture and were collected in filter paper. Indirect hemmaglutination
(HgI) and indirect immunofluorescence (IFI) were performed. The dilution titer considered reactive by
both techniques was ≥ 1:16 The results showed that in Uspero 3 (1.2%) out of 252 samples analyzed by
HgI were reactive (1:16, 1:16, 1:64) and reactive titers in samples analyzed by IFI (1:16, 1:32, 1:64)
also were observed. These results correspond to 3-, 10- and 15-year-old children, respectively. In Chuquiapan, six out of 157 samples analyzed by both techniques were reactive (3.82%), five of them with
dilution titers of (1:16) and one (1.32), these results correspond to four adults and two children. The
samples obtained from Rancho seco and analyzed by HgI showed reactive titers; 10 (8.77%) out of 114,
six samples with dilution titers 1:16, three 1:32 and one 1:64. Similar results were obtained in samples
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ABSTRACTS
analyzed by IFI: the samples studied corresponded to eight children and two adultts.The results obtained
suggest that both (HgI and IFI) have similar specificity and sensibility, so they could be an important
tool in the trypanosoniasis diagnostic. It is necessary to improve the samples number in order to understand the real problem in this state. The fundamental samples analyzed in this study was the infant
population. Since 13 (68%) of the 19 reactivate samples corresponded to child younger than 16 years
old.
389
Population Dynamics of Philometra carolinensis, an Ovarian Philometrid in the Spotted Seatrout
(Cynoscion nebulosus) in South Carolina, USA. G.R. PÉREZ, W.A. ROUMILLAT, E.J. LEVESQUE, Inshore
Fisheries Section, Marine Resources Division, South Carolina Department of Natural Resources,
Charleston SC, and I. DE BURON*, Department of Biology, College of Charleston, Charleston SC,
USA.
Philometra carolinensis is a philometrid nematode found in the female gonads of spotted seatrout, Cynoscion nebulosus, and so far only reported from fish captured in the South Carolina estuarine system. The
seasonal occurrence of this parasite, based upon presence of female worms only, was studied according to
fish size (representing age) and sexual maturity as well as abiotic factors (water dissolved oxygen, salinity,
and temperature). Fish were collected via the use of trammel nets and from local fishing tournaments. A
total of 901 female spotted seatrout were collected from March 2005 through February 2007. Overall
prevalence of infection was 11.2%. Each year female worms occurred exclusively in mature fish and
during the spotted seatrout spawning season from May through August. Worms were tallied only during
the second spawning season and showed a typical aggregated distribution. Overall infection peaked in
June with a prevalence of 43.1% and a mean intensity of 6.3 ± 1.5 worms (n = 109). In July prevalence
and intensity of infection dropped to 10.4% and 1.6 ± 0.4 worms, respectively (n = 48). An analysis
that focused on worm developmental stage showed that most worms found in May were subgravid
whereas the number of gravid worms peaked in June with each dropping abruptly in July; only necrotic
worms were found in August. This parasite was found in spotted seatrout captured in each estuary
sampled and abiotic factors did not affect the occurrence of the nematode in the fish host. Results of this
study suggest that female P. carolinensis development in the flounder host is likely linked to physiological
cues triggered in spawning female fish.
390
Development of Philometra overstreeti and Philometroides paralichthydis in the Cyclopoid Copepod
Oithona colcarva. T. BRYAN and I. DE BURON*, Department of Biology, College of Charleston,
Charleston SC, USA.
Philometra overstreeti and Philometroides paralichthydis are philometrid species commonly found in the
southern flounder, Paralichthys lethostigma. These parasite species were only recently described and their
life cycles are unknown. Copepods belonging to five cyclopoid species common to waters where fish are
found to be infected were exposed to larvae collected from gravid females of both philometrid species. Of
the five species tested, Acartia tonsa, Parvocalanus crassirostris, Saphirella tropica, Temora turbinata, and
Oithona colcarva, O. colcarva was the only one in which larvae of both philometrid species successfully
developed. Experiments were carried out in a salinity of 15 mg/L at 23°C. Times of successive molts
were determined on live organisms and verified via serial semi-thin sections and transmission electron
microscopy for further accuracy. For both philometrid species, the first molt from L1 to L2 was observed
as early as 24 hours post exposure whereas the second molt from L2 to L3 occurred 4.5 to 7 days postexposure. Infected copepods progressively deteriorated and did not survive past 11 days except for rare
cases. All L3 larvae were observed to remain in their last molt for as long as their host copepod survived.
(Funded in part by a Summer Undergraduate Research with Faculty grant from the College of Charleston.)
391
Boophilus microplus (Acari: Ixodidae) on Cattle Distribution in Navolato y Mocorito, Sinaloa, México.
S.M. GAXIOLA-CAMACHO*, Area de Parasitología, Facultad de Medicina Veterinaria y Zootecnia,
Universidad Autónoma de Sinaloa, Culiacán, Sinaloa, M.T. QUINTERO-MARTÍNEZ, Departamento de
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ABSTRACTS
Parasitología-FMVZ-UNAM, México DF, J.J. PORTILLO-LOERA, Area de Bioestadística, FMVZ-UAS,
Culiacán, Sinaloa, N. CASTRO-DEL CAMPO, Area Parasitología, FMVZ-UAS, Culiacán, Sinaloa,
México, J.E. BORBOLLA-IBARRA, Area de Parasitología y Nutrición, FMVZ-UAS, Culiacán, Sinaloa,
and J. ORDOÑEZ-MANRIQUEZ, Area de Parasitologia, FMVZ-UAS, Culiacán, Sinaloa, México.
The objective of this study was to know and inform on the distribution of the ticks in the cattle of the
municipalities into Navolato y Mocorito, Sinaloa, México. In a design of simple random cross-sectional
study, 207 farms were sampled and analyzed, taking 20 ticks by farm. The samples were collected from
bovine cross of Cebu (Bos taurus and Bos indicus) in three different production systems from meat, milk
and double purpose. The farms were sampled once, making the sampling during period of July of 2005
to June 2006. The ticks were taken in off all the body of bovine, when the sizes of the ticks were up 4.5
mm. The samples were deposited in alcohol for carried out to the laboratory for posterior identification.
In all the operations and regions of the analyzed municipalities was observed Boophilus microplus, and in
the 5.8% (12) of studied the farms was found at least one sample of Amblyomma cajennense ticks, in the
different samplings. B. microplus was more frequent in “Los Altos” region and divides to power station of
the municipality (44%) and (31%), respectively, than in coastal region (79%) in Navolato municipality.
An extended distribution of B. microplus was detected in the entire municipality, being the maximum
number during the month of May, for Mocorito municipality and month of September for Navolato
municipality, up to 274 ticks by cow and in low level in January with two ticks by cow, in both municipalities. In conclusion, this study shows that the distribution of Boophilus microplus is observed during a
year and the geographical regions studied in order to be able to make studies of resistance to the acaricides and to implementer control measures.
392
Presence of Populations of Haematobia irritans on Cattle of Double Purpose (Meat and Milk) in
Pasturing in the South of Sinaloa State, México. S.M. GAXIOLA-CAMACHO*, Area de Parasitología,
FMVZ-UAS, Culiacán, Sinaloa, M.T. QUINTERO-MARTÍNEZ, Departamento de Parasitología, FMVZUNAM, México DF, J.E. BORBOLLA-IBARRA, Area de Parasitología y Nutrición, FMVZ-UAS, Culiacán,
Sinaloa, J.J. PORTILLO-LOERA, Area de Bioestadística, FMVZ-UAS, Culiacán, Sinaloa, and N.
CASTRO-DEL CAMPO, Area de Parasitología, FMVZ-UAS, Culiacán, Sinaloa, México.
The seasonal evolution of the population of fly of the Haematobia irritans were recorded during weekly
counts of Cebu crossed cows pasturing in the municipalities of Rosario and Escuinapa in the Southern
zone of the state of Sinaloa. Data was collected from February 15, 2005 to January 31, 2006. Maximum
densities of four flies per cow were registered throughout the year, with exception of the second and
third weeks of January. The adult flies never disappeared from the cows, indicating that if diapause
happens in that latitude, it does not affect the entire population of flies. The greater level of abundance
(403 flies/cows) registered in May of 2005. The density of flies reduced between November 10, 2005
and January 12, 2006, and increased during the period from March 14 to May 23, 2005. The climatic
variables that best correlated with the counts of flies were the minimum temperature, the average
temperature, and precipitation. The percentage of mortality of the fly population in the field by organic
phosphorous compound (coumaphos) and a piretroide (deltametrina), were 84% and 63%, respectively.
393
Evaluation of the Biological Reproduction of Two Stocks of Boophilus microplus. S.M. GAXIOLACAMACHO*, Area de Parasitología, FMVZ-UAS, Culiacán, Sinaloa, Z. GARCÍA-VÁZQUEZ, DirectorCENID-Microbiología-INIFAP, Jiutepec, Morelos, C. CRUZ-VÁZQUEZ, Area de Parasitología, Instiruto
Tecnológico Agropecuario “El LLano,” Aguascalientes, J.J. PORTILLO-LOERA, Area de Bioestadistica,
FMVZ-UAS, Culiacán, Sinaloa, M.T. QUINTERO-MARTÍNEZ, Departamento de Parasitología, FMVZUNAM, México DF, C. VÁSQUEZ-PELÁEZ, Departamento de Bioestadística y Genética, FMVZ-UNAM,
México DF, and R. ROSARIO-CRUZ, Area de Parasitología, CENID-Microbiología, INIFAP, Jiutepec,
Morelos, México.
The objective of the present work was to study the index of Reproductive Eficience (IRE) and the Index
Reproductive Fitness (IRF) of two stocks of B. microplus, one collected in the field (native) and one
reference stock, maintained in conditions of laboratory during two years. From February 2001 to
February 2004, ingorged ticks were collected monthly, weighed and maintained in the laboratory until
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ABSTRACTS
oviposition; the ovigeras masses were weighed individually and then incubated to await the release of
larvae in order to measure the IER and the IAR of each. The weights of the ingorged ticks were grouped
in ranks of 100 mg; information was analyzed by variance and a Duncan multiple rank test (P < 0.05).
Pearson correlation coefficients were calculated (P < 0.01) to consider the association between the
weight of the ingorged ticks and the weight and number of eggs and larvae. The native stock showed a
higher ingorged weight than the reference stock. The IRE and the IRF in both stocks were similar in all
ranks of weight to the ingorged quadratic tendency. Both indexes by rank of weight of ingorged were
always higher in the native stock (P < 0.05). Throughout the study, the IRE and the IRF of both stocks
showed differences (P < 0.01), the native stock being the one with better behavior in both indexes. The
correlation that was highly significant in all the parameters was oviposition (0.94 and 0.91) for the
native and reference stocks, respectively.
394
Population Dynamics of the Parasitic State of Boophilus microplus in Bovines of the Municipality of
Culiacán, Sinaloa, México. S.M. GAXIOLA-CAMACHO, Area de Parasitología, FMVZ-UAS, Culiacán,
Sinaloa, Z. GARCÍA-VÁZQUEZ, Director, CENID-Microbiología, INIFAP, Jiutepec, Morelos, C. CRUZVÁZQUEZ, Area de Parasitología, ITA, “El Llano,” Aguascalientes, M.T. QUINTERO-MARTÍNEZ*,
Departamento de Parasitología, FMVZ-UNAM, México DF, J.J. PORTILLO-LOERA, Area de Bioestadística, FNVZ-UAS, Culiacán, Simaloa, C. VÁSQUEZ-PELÁEZ, Departamento de Genética y Bioestadística, FMVZ-UNAM, México DF, R. ROSARIO-CRUZ, Area de Parasitología, CENIDH-INIFAP, Jiutepec,
Morelos, and J.E. BORBOLLA-IBARRA, Area de Parasitología, FMVZ-UAS, Culiacán, Sinaloa, México.
Summary: The objective of this study was to determine the population dynamics of Boophuilus microplus
in cattle naturally infested in the municipality of Culiacán, Sinaloa, México, and its relation with the
temperature, pluvial precipitation and evaporation. The infestation was determined weekly over a period
of two years by means of individual counts of B. microplus larvae, nymphs and adult females in the
bovines. The linear correlation between the climatic variables with the parasitic states was determined
and the best model of multiple regression under the criterion of number of parameters was considered.
The infestation by B. microplus showed different peaks of activity for each one of the parasitic stages
during the mentioned period. The larvae predominated from April to July, with small peaks of activity in
the last week of autumn. The nymphs predominated from March to May, showing their highest peak in
the second week of May. Finally, the adult ticks showed their highest activity during the summer months.
It was observed that the effect of temperature and evaporation were the climatic factors of greater
relevance (p < 0.01) in the presence of larvae and nymphs, whereas for the adult stage, the temperature
and environmental precipitation showed to be the more important climatic variables (p < 0.01). These
results allow us to establish strategic treatments for their control, with reccomendations to establish a
program to apply ixodicidas at the beginning of the month of March and September.
395
Identification of Endoparasites in Snakes Boidae, Pitonidae and Viperidae Families from the Zoo Park
in Culiacán, Sinaloa. S.M. GAXIOLA-CAMACHO, N. CASTRO-DEL CAMPO, C. BARRAZA-TIZOC*,
J.E. BORBOLLA-IBARRA, I. QUINTERO-OSUNA, N. CÁRCAMO-ARÉCHIGA, S.D. COTA-GUAJARDO,
Y. VILLALBA-ROBLES, J. GAXIOLA-MONTOYA, J.A. PÉREZ-CORRALES, T. MARTÍNEZ-BASTIDAS and
M.A. RODRÍGUEZ-GAXIOLA, Parasitology Area, Faculty of Veterinarian Medicine and Zootechnic,
University Autonomous of Sinaloa State, Culiacán, Sinaloa, México.
Reptiles have covered the Earth’s surface for millions of years to this day due to their evolution and
adaptation abilities. Reptiles are diverse and interesting vertebrates; within this group, 2,700 species of
snakes, distributed throughout the world, have been identified. México has an important percentage of
families, genera, species and subspecies of these animals, being the richest country in reptiles. The aim of
this work was to determine the incidence of endoparsites in snakes of the Boidae, Pitonidae and Viperidae families, from the herpetario of the Zoo Park of Culiacán, Sinaloa. Five individuals from the
Boidae family, two from the Pitonidae family, and six from the Viperidae family were selected randomly.
Their excrements were collected and processed by flotation and sedimentation techniques to determine
the presence of endoparasites. Results showed that, of the 13 snakes analyzed, eight were positive for
Isospora (61.5%), and one was positive for Entamoeba (7.6%) and Strongiloides (7.6%). Because our
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ABSTRACTS
results demonstrate that snakes are susceptible to parasitic diseases, routine samplings should be done in
order to contribute information about the parasites that can affect snakes, and to identify if these species
can cause sanitary problems.
396
Necropsy Results in Capuchino (Zebus apella) and Yellow Hand Titi (Callicebus torquatos) Monkeys.
S.M. GAXIOLA-CAMACHO, N. CASTRO-DEL CAMPO, C. BARRAZA-TIZOC*, J. BORBOLLA-IBARRA,
N. CÁRCAMO-ARÉCHIGA, Y. VILLALBA-ROBLES, S.D. COTA-GUAJARDO, J. GAXIOLA-MONTOYA,
J.A. PÉREZ-CORRALES, I. QUINTERO-OSUNA, T. MARTÍNEZ-BASTIDAS, M.A. RODRÍGUEZGAXIOLA, C. SOSA-GUTIÉRREZ and E.G. ESPÍNOLA-RUIZ, Parasitology Area, FMVZ, University
Autonomous of Sinaloa. Culiacán, Sinaloa, México.
Many species of monkeys are in danger of extinction by the loss of the habitat and because they are used
widely in laboratory research. On the other hand, commerce of primates as pets has caused legal or illegal
continuous introduction in Mexico. The transition of the wildlife into captivity causes stress due to
handling and a badly balanced diet. Monkeys are exposed to various diseases, among them parasites, that
can lead to their death. The objective of this work was to report autopsy findings of five adult male
monkeys (one capuchin and four yellow hand titi) in Culiacan, Sinaloa, from a local, run-down company
where they ate fruits and dog food and received palliative treatment for thre days against gastrointestinal
parasites. The monkeys showed distended abdomens, diarrhea, cachexia and hypothermia, and finally
died. When the Monkeys were inspected overall, 10- to 19-cm-long filaria were found in the lungs,
thorax and subcutaneous tissue that were identified later as Mansonella. Microfilaria measuring 700 to
900 microns were found in the blood samples, which were fatal to the monkeys.
397
Comparison Between Snap 3Dx and Cytological Test in Diagnostic for Ehrlichia canis in Dogs of
Sinaloa, México. C. SOSA-GUTIÉRREZ*, S.M. GAXIOLA-CAMACHO, S.D. COTA-GUAJARDO,
Parasitology Area, FMVZ, University Autonomous of Sinaloa, Culiacán, Sinaloa, M.T. QUINTEROMARTÍNEZ, Parasitology Department, FMVZ, UNAM, México DF, N. CASTRO-DEL CAMPO, C.
BARRAZA-TIZOC, N. CÁRCAMO-ARÉCHIGA, J. GAXIOLA-MONTOYA and J.A. PÉREZ-CORRALES,
Parasitology Area, FMVZ, University Autonomous of Sinaloa, Culiacán, Sinaloa, México.
Canine Monocytic Ehrlichiosis (CME) is a dog’s disease world-wide distribution. The etiologic agent is
the rickettsia Ehrlichia canis. This disease is transmitted by the brown tick of the dog (Rhipicephalus
sanguineus) and its sinology can vary depending the phase in which it finds one begins with an acute
process characterized by depression, anorexy, lethargy, loss of weight and fever, followed by a subclinical
stage. In México, the first case of canine monocytic Ehrlichiosis was diagnosed in 1996. The method
definitive diagnosis of E. canis is the visualization of morulae within the monocitos in cytology. In order
to determine the method diagnose more effective used against E. canis in México, it is necessary to
compare them; with this aim, 40 infected sanguineous samples were obtained of dog natural way in
different veterinary clinics from north, center and the south of the state, which were analyzed by means
of ELISA (Snap 3Dx) measuring antibodies (Ab) and cytological test using Wright stain. The positive
results to E. canis by ELISA (snap 3Dx) means of 28 (70%) and the cytology test with 26 (65%). The
statistical analysis was by means of the Index of J of Youden with an interval of 95% confidence. The
prevalence in this case was of 70%, the patients correctly diagnosed was of 70%, Sensitivity 75%,
Specificity 58.33%, Likehood ratio (+) 80.77% and LR (-) 50% with a Coefficient of Positive Probability 1.80 and Negative Coefficient of Probability 0.43. One concludes that the use of the method diagnose ELISA (Snap 3Dx) is better than cytology test is adapted for diagnose of E. canis.
398
Zoonotic Dermatopathies in Companion Animals in Sinaloa, México. S.M. GAXIOLA-CAMACHO, S.D.
COTA-GUAJARDO, N. CASTRO-DEL CAMPO*, C. SOSA-GUTIÉRREZ, N. CARCAMO-ARECHIGA, C.
BARRAZA-TIZOC, J. GAXIOLA-MONTOYA, J.A. PÉREZ-CORRALES, J. BORBOLLA-IBARRA, Y.
VILLALBA-ROBLES, E.G. ESPÍNOLA-RUIZ, K. SICAIROS-CAÑAS, B. ROMERO-MÉNDEZ and M.
PADILLA, Parasitology Area, FMVZ, University Autonomous of Sinaloa, Culiacán, Sinaloa, México.
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ABSTRACTS
Among the main health problems that affect dogs and cats in Sinaloa, México are dermatopathies, many
of which are zoonotics. Based on the analysis of 161 skin-scratch samples studied between January 2005
to February 2007, the pathologies that most affected dogs in this region were dermatofitosis 33.5% (54
samples), demodicosis 2.4% (36 samples), and scabiosis 8.1% (13 samples). In cats, dermatofitosis
represent 28.6% (two samples), demodicosis 14.3% (one sample), and scabiosis 14.3% (one sample).
M. canis is the most common cause of dermatofitosis (in cats, up to 98% of the cases) and affects the
human being. Close to 50% of humans exposed acquire the disease; in 70% of all the homes affected, at
least one person has the disease; 30% of dermatofitosis in humans in urban areas has been associated
with direct contact with companion animals; the occupational risk of acquiring a dermatofitosis is high.
Sarcoptes scabei affects man as an incidental host, the signs of which are prurito and popular dermatitis.
The largest number of cases in humans has been reported as an occupational risk, but also commonly by
direct contact with a sick pet. Both pathologies require treatment that may be toxic and thereby must be
carefully administrated, especially in children and pregnant women.
399
Gastrointestinal Parasites in Dogs and Cats: Underestimated Zoonoses. S.M. GAXIOLA-CAMACHO,
S.D. COTA-GUAJARDO*, N. CASTRO-DEL CAMPO, C. SOSA-GUTIÉRREZ, C. BARRAZA-TIZOC, N.
CÁRCAMO-ARÉCHIGA, J. GAXIOLA-MONTOYA, J.A. PÉREZ-CORRALES, J. BORBOLLA-IBARRA, Y.
VILLALBA-ROBLES, M. MILLÁN-VARELA, C. SALGADO-VEGA and J. DANIEL, Parasitology Area,
FMVZ, University Autonomous of Sinaloa, Culiacán, Sinaloa, México.
Pet owners who understand the importance of routine de-worming are few. This is due the lack of
knowledge about the zoonotic potential of some of the more common gastrointestinal parasites in dogs
and cats, such as Ancylostoma, Dipylidium and Giardia. In order to establish which are the most common
gastrointestinal parasites in dogs and cats in Sinaloa, México, the previously obtained results from 980
feces samples (76 from cats) were reviewed. Ancylosmota was the most common (15% [146 samples] in
dogs and 24% [18 samples] in cats), followed by Giardia (2.3% [22 samples] in dogs and 1.3% [one
sample] in cats). Parasites found include Dypilidium (1.6%, 16 samples), Taenia (0.4%, four samples)
and Entamoeba (0.20%, 2 samples). Dipylidium caninum and Echinococcus are the zoonotic cestodosis of
major importance in dogs and cats; the former is acquired through flea bites in urban areas mainly
because of crowding due to population density. Giardia’s zoonotic potential has been proven and it is
known that humans can be infected through direct contact. Amibiasis caused by Entamoeba histolytica is
more common in humans than dogs or cats and is transmitted through ingestion of contaminated feces.
Finally, Ancylostoma canium is a nematode that was considered species specific, but today it is accepted
that it can infect humans, who acquire it mainly by larvae penetrating the skin.
400
Typical and Atypical Amebic Hepatic Abcesses in Children: Experience of 128 Cases Treated at the
Instituto Nacional de Pediatria, México. O. VAZQUEZ-TSUJI*, Laboratorio de Biologia Molecular y
Microscopia Electronica, Facultad Mexicana de Medicina, Universidad La Salle, México, M.P.
MÁRQUEZ-AGUIRRE, Departamento de Terapia Intensiva, Instituto Naiconal de Pediatria, México, T.
CAMPOS-RIVERA, Servicio de Parasitologia y Micologia, Instituto Nacional de Pediatria, México, Y.
GARCIA-YANEZ, UNAM, and A. RONDÁN-ZÁRATE, Laboratorio de Biologia Molecular y Microscopia
Electronica, Facultad Mexicana de Medicina, Universidad La Salle, México.
Introduction: Hepatic amebic absceso (HAA) is a problem in the pediatric population. The typical
clinical features are fever, hepatomegaly and pain in the upper right quadrant of the abdomen, altogether
with leukocytosis, neutrophilia and serum antibodies against Entamoeba histolytica. Objective: Our
objective was to acquaint the frequency of HAA presenting in children with the typical clinical features in
comparison with the atypical presentations. Methods: We carried out a retrospective study of 128 cases
of HAA confirmed by laboratory and image techniques between 1973 and 2004. Variables related to the
clinical features, radiological diagnosis and laboratory diagnosis were obtained. Results: We reviewed 128
cases with clinical diagnosis of HAA confirmed by laboratory and radiology. Incidence by age group was:
infants 53.12% (n = 68), scholars 24.21% (n = 31), teenagers 21.87% (n = 28) and lactants 0.8% (n
= 1). As for gender, 54.68% (n = 70) were female, and 45.32% (n = 58) were male. When reviewing
the history of the patients, 91.40% (n = 117) had had fever and 93.75% (n = 120) had had malaise
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ABSTRACTS
prior to being admitted; 93.75% (n = 120) presented hepatomegaly, 87.5% (n = 112) had upper right
quadrant pain, 79.68% (n = 102) had fever during their hospital stay, 8.59% (n = 11) had jaundice,
49.21% (n = 63) had anemia, 79.68% (n = 102) leukocytosis, 53.90% (n = 69) neutrophilia; 84.37%
(n = 108) had normal AST and ALT, 92.18% (n = 118) elevated alkaline phosphatase; 97.65% (n =
125) had a positive serology (indirect hemaglutination and ELISA). Discussion: The diagnosis of HAA
may be quite complex, especially when the typical clinical triad is absent. of all the cases, 79.68% presented with the typical clinical triad described in literatre. However, 20.32% did not present such a triad.
401
Ocular Larva Migrans in Pediatric Patients: A Report of 10 Cases. O. VAZQUEZ-TSUJI*, Laboratorio de
Biologia Molecular y Microscopia Electronica, Facultad Mexicana de Medicina, Universidad La Salle,
México, T. CAMPOS-RIVERA, Servicio de Parasitología y Micología, Instituto Nacional de Pediatría,
México, and R.H. MEDINA-CAMPOS, Residente de Med Interna del Instituto Nacional de Ciencias
Medicas y Nutricion, Salvador Zubiran, México.
Introduction: Larva migrans is a zoonosis produced by Toxocara canis and Toxocara cati, ascarid parasites
of dogs and cats, respectively. In ocular larva migrans, the larvae produce strabism, leukocoria, endophtalmitis, chronic inflammation of the posterior chamber, or chronic granulomas in the retina, all of
which may lead to blindness in the affected eye. Objective: In this work, we present our experience in
diagnosing and treating 10 cases of ocular larva migrans at the Instituto Nacional de Pediatría in México
City. Materials and Methods. We carried out a descriptive, retrospective study of cases of ocular larva
migrans confirmed either by ophthalmoscopy and serology or by slit lamp and serology. Results: Ten
cases of ocular larva migrans were detected in seven girls and three boys within an age range of 3 to 14
years. Two of the patients came from the state of Guerrero, one from Hidalgo, one from Estado de
México, one from Tabasco, one from Tamaulipas, one from Oaxaca, and two from Distrito Federal. All of
the patients had been admitted with a diagnosis other than ocular larva migrans. Geophagy was identified in 40% of the patients, while another 30% had a history of contact with dogs. Eight patients
presented with late secuelae, whereas two patients presented with active ocular larva migrans. Conclusions: All of the patients had diminished visual acuity. We conclude that all patients presenting with
diminished visual acuity and history of close contact with dogs should be evaluated for ocular larva
migrans, so that early cases may be detected.
402
Digenean Metacercariae Parasitizing the Hydromedusa Clytia folleata (McCrady, 1859) from Northern
Quintana Roo, México. M.Y. MORALES-HERNÁNDEZ*, Posgrado en Ciencias del Mar y Limnología,
UNAM, Puerto Morelos, Quintana Roo; M.L. AGUIRRE-MACEDO, Laboratorio de Patología Acuática,
CINVESTAV, Unidad Mérida, Mérida,Yucatán; and M.L. SEGURA-PUERTAS, Laboratorio de Zooplancton, ICMYL, Unidad Académica, Puerto Morelos, Quintana Roo, México.
The parasites of Clytia folleata were studied over an annual cycle in the northern zone of Quintana Roo
coast. Hydromedusae were collected monthly from January to December 2005 in 12 sampling locations
by horizontal drags with a standard plankton net, and fixed in 4% formaldyhe. Hydromedusae with
parasites were quantified and the metacercariae were removed from the tissues and mounted in glycerine
gelatin. Six morphotypes of metacercariae were identified and characterized using standard metrics,
including the arithmetic average, the standard deviation and maximum and minimum values, expressed
in micrometers, of their main morphological characteristics. In general, the percentage of infected
hydromedusae was low (0.05–2.87 %). Most individual hydromedusae were parasitized with 1–2
individual metacercariae and intensities of 3–4 were infrequent. The largest number of individuals and
morphotypes (207 and 5, respectively) were recorded in May, while the rest of the year the count was
below (1–17 individuals and 1–4 morphotypes). The reported metacercariae could well belong to any of
the families Lepocreadiidae, Fellodistomidae, Apocreadiidae, Homalometridae, Acantocolphidae or
Zoogonidae. Nevertheless, a detailed study of the parasites in the region, examining live samples of
possible definitive hosts and/or obtaining the adults through of experimental infections would help with
their specific identification.
231
ABSTRACTS
403
Intestinal Helminths in Ciconiiform Birds from the Chuburna Saltmarsh in the Yucatán Peninsula. A.O.
BARRERA-GUZMÁN* and S. GUILLEN-HERNÁNDEZ, Departamento de Biología Marina, Campus de
Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México.
Helminths are important components of wetland faunas and its study may provide valuable information
about these habitats. Many species that include fish and aquatic invertebrates as intermediate hosts in
their life cycles use ciconiiform birds as definitive hosts. These birds are common in wetlands; however,
records of their helminths in México are very scarce. In this work, the helminth fauna from six species of
ciconiiform birds from Chuburna saltmarsh in the state of Yucatán are described. From February 2005 to
April 2006, a total of 20 birds were examined for helminths: eight Egretta rufescens, two Egretta caerulea,
three Egretta tricolor, three Platalea ajaja, three Butorides virescens, and one Cochlearius cochlearius. Prevalence, mean intensity and mean abundance were calculated for each helminth species only in the host
species with more than one individual. Thirteen species of helminths were found, including four digeneans (Cotylotretus grandis, Euhaplorchis californiensis, Ascocotyle sp., and Apharyngostrigea sp.), six cestodes
(Glossocercus caribaensis, Glossocercus auritus, Cyclustera capito, Cyclustera ibisae, Gryporhynchidae gen. sp.
1 and Gryporhynchidae gen. sp. 2), two nematodes (Contracaecum sp. and Anisakidae gen. sp.), and one
acanthocephalan (Southwellina hispida). Ascocotyle sp. showed the highest prevalence, mean intensity and
mean abundance values.
404
Richness and Endemism of Helminth Parasites of Freshwater Fishes in México. R. AGUILARAGUILAR*, Departamento de Biología Evolutiva, Facultad de Ciencias, UNAM, A. MARTÍNEZAQUINO, Departamento de Zoología, Instituto de Biología, UNAM, and R. CONTRERAS-MEDINA,
Departamento de Biología Evolutiva, Facultad de Ciencias, UNAM, México.
Distribution records of 152 adult helminth taxa parasites of freshwater fishes in México were analyzed to
determine areas of high richness and endemism. Distribution maps were prepared for each taxon and
overlaid onto a map of México divided into 1 x 1 degree grid-cells. Richness was determined by counting
of records of helminth species in each grid-cell. A corrected weighted endemism index was calculated for
each grid-cell, and the relationship between richness and endemicity was analysed with an Olmstead–
Tukey corner test of association. Five areas of high richness and endemism were identified: (1) Los
Tuxtlas and the Papaloapan river basin, on the Gulf of México; (2) the Grijalva–Usumacinta basin near
the Gulf of México coastal plain; (3) the Yucatán Peninsula; (4) the Sierra de Manantlán Biosphere
Reserve in western México; and (5) the Pátzcuaro lake in central México. The distribution of richness
and endemism of helminth parasites of freshwater fishes in México is congruent with distribution
patterns described for other freshwater taxa in México. Patterns of richness and/or endemism in the
studied areas can be explained by the ichthyological composition of their bodies of water. This study
establishes an alternative way of analyzing the relationship between richness and endemicity, and suggests
that helminths can make valuable contributions to regionalization of geographic areas and for identification of rich and biologically complex areas with potential for conservation of aquatic systems.
405
Coleccion Nacional he Helmintos (CNHE): 75 Years Inventorying Mexican Parasite Diversity. R.M.
LAMOTHE-ARGUMEDO*, G. PÉREZ-PONCE DE LEÓN, L. GARCÍA-PRIETO and D. OSORIOSARABIA, Laboratorio de Helmintología, Instituto de Biología, UNAM, Ciudad Universitaria, México
DF, México.
The Coleccion Nacional de Helmintos (CNHE), housed at Instituto de Biologia, UNAM, México City,
was funded in 1932 by Eduardo Caballero; since then, this collection has supported inventory work to
describe helminth diversity from México. Former curators were Eduardo Caballero, Margarita BravoHollis and Jorge Caballero-Deloya. Rafael Lamothe-Argumedo has been the curator since 1980. Information contained in the collection has been catalogued twice (1973, 1997). At present, the CNHE is
one of the largest and more dynamic collections of helminths in the Americas; it contains 45,500 specimens, representing 1,354 species organized in 5,650 lots, with representatives of all the helminth groups:
Plathyhelminthes (Temnocephala: six species; Turbellaria: 14 species; Monogenea: 191 species; Digenea:
232
ABSTRACTS
548 species; Cestoidea: 138 species), Acanthocephala (45 species), Nematoda (363) species), and
Hirudinea (48 species). Specimens have been collected in practically all Mexican territory (30 of the 32
states); in addition, voucher and type specimens of helminth collected in 34 countries have been deposited, mainly from Latin America. Four-hundred twenty-nine of the 1,354 deposited species are holotypes. The global rate of annual increase of the collection is 18.2 species, 606 specimens, and 75.3 lots
per year. In the last 10 years, however, these rates have raisen to 99.4 species, 1,488 specimens, and
261.5 lots per year. In addition, during this same period, 362 publications have resulted from research
both in the CNHE and from specimens loaned from, or deposited into, the CNHE as types or vouchers.
The inventory of the helminth parasites of wildlife vertebrates in México is far from complete. Huge
progress has been made since the collection was established 75 years ago; however, sampling effort
requires the involvement of more systematyst in the next years, with a concomitant increase in the
infrastructure of the national collection to support systematic work and information retrieval to guarantee that deposited specimens will be kept safe in the future.
406
Diversity of Ticks in México: An Analysis of Recent Advances. C. GUZMÁN-GORNEJO*, G. MONTIELPARRA, R. PAREDES-LEÓN and T.M. PÉREZ, Colección Nacional de Ácaros, Instituto de Biología,
UNAM, Ciudad Universitaria, Copilco, Coyoacán, México DF, México.
The knowledge of the occurrence of ticks in México dates from pre-Hispanic times; however, the first
researcher to study this group in México was A. Dugès. The main taxonomic contributions were made
by foreign and national researchers during the first half of the last century, including the study of ticks as
vectors of microorganisms causing diseases. All published information was compiled by Hoffmann in
1962 in a work entitled Monografía de los Ixodoidea de México. The aim of this study is to determine the
current tick diversity in México, and analyze the progress in the study of this group since the work of
Hoffmann to the present. We conducted bibliographic database searches (CAB Abstracts, BIOSIS,
Biological Sciences), and used information contained in the Colección Nacional de Ácaros (CNAC)
database. The information obtained was catalogued into: (1) medical importance, including human
records and microorganismal transmition, (2) veterinary importance, including works dealing with
molecular analysis, immunology, epidemiology, physiology, ecology and eradication of ticks associated to
domestic animals and livestock, and (3) systematic, including taxonomic records, geographic distribution
and ecology of ticks associated to wild animals. To date, 210 works dealing with ticks have been published since 1962. Six of them (2.86%) are focused on the medical importance of ticks, 164 (78.1%) on
veterinary aspects, and 40 (19.04%) on systematics. Hoffmann’s contribution listed 59 valid tick species.
Since then, 27 additional species have been recorded, totaling 86 species belonging to nine genera and
two families (Argasidae and Ixodidae); 50 of these are deposited in the CNAC, representing 58.14% of
the total reported species. The knowledge generated in our country about ticks in the last 45 years is
focused mainly on ticks associated with livestock. Future studies should include ticks parasites of wild
vertebrates, integrating ecological, biogeographical, evolutionary, and epidemiological aspects.
407
Phylogenetic Analysis of Some Species of the Genus Polymorphus Lühe, 1911 from North America
(Polymorphidae: Acanthocephala) Based on Mitochondrial Gene Sequences. M. GARCÍA-VARELA,
Departamento de Zoología, Instituto de Biología, UNAM, México.
Adults of the family Polymorphidae Meyer, 1931 are intestinal parasites of marine mammals or fisheating birds. The life cycle typically includes a crustacean as intermediate host and may include a fish as
paratenic host. The family Polymorphidae contains 10 genera, with approximately 127 species diagnosed
by having a spinose trunk, bulbose proboscis, double-walled proboscis receptacle, and usually four
tubular cement glands. Currently, the genus Polymorphus is considered as the most diverse within Polymorphidae, with 28 described species. Amphipods serve as first intermediate hosts, and waterfowl
definitive hosts are distributed worldwide; however, in North America, the major diversity of these
worms is associated with ducks and geese. Phylogenetic analyses based on mitochondrial sequences
suggests that the genus Polymorphus is not monophyletic and that the genus represents a complex of
species that should be reclassified using morphological, ecological and molecular characters.
233
ABSTRACTS
408
Morphological and Molecular Variation in Oligogonotylus manteri Watson, 1976 (Digenea: Cryptogonimidae) in Middle American Cichlids (Osteichthyes: Cichlidae). U. RAZO-MENDIVIL*, R. ROSASVALDEZ and G. PÉREZ-PONCE DE LEÓN, Instituto de Biologia, UNAM, México.
Several species of cryptogonimids have been described as parasites of cichlids in Middle American
cichlids. Particularly, the monotypic genus Oligogonotylus was erected by Watson (1976) to include O.
manteri as a parasite of several species of cichlids (Hypsophrys nicaraguensis Günther, 1864, Amphilophus
labiatus Günther, 1864), A. citrinellus Günther, 1864), A. rostratus Gill, 1877, and Vieja maculicauda
Regan, 1905) in Lake Nicaragua. In México, adults of this digenean have been reported in at least 15
species of fishes in 33 localities of southeastern México, corresponding to six States (Campeche, Chiapas,
Quintana Roo, Tabasco, Veracruz, and Yucatán). Eleven of the 15 host species are members of the
Cichlidae, so this species of digenean is considered to be part of the biogeographical core helminth fauna
of cichlids (in a biogeographical sense). During the last two years, specimens of O. manteri were collected from Cichlasoma urophthalmus in several localities of Yucatán, Tabasco, and Veracruz States. Some
morphological differences were found with respect to the distribution and extension of vitelline follicles
along the body, and we were able to discriminate between two morphotypes. Our main objective is to
present some data on the intraspecific morphological variability of this species, and to contrast that
variability with genetic divergence levels by using sequences of the 28S ribosomal RNA gene. Our results
indicate that genetic divergence levels correspond with the two morphotypes. Whether or not this
represents a new species needs to be determined by extending the sampling effort to other localities and
hosts within the distributional range of the species, as well as by using other ribosomal (ITS1 and ITS2)
and mitochondrial (COI) genes. The use of a combination of both morphology and molecular data will
allow us, in the near future, a better understanding of parasite diversity in freshwater fishes.
409
Scanning Electron Microscopy of Seven Species of Polymorphid (Acanthocephala) Parasites of Birds in
México. B. MENDOZA-GARFIAS*, M. GARCÍA-VARELA and G. PÉREZ-PONCE DE LEÓN, Instituto de
Biologia. UNAM, México.
Among helminth parasites of wildlife vertebrates in México, Acanthocephalans show the lowest species
richness when compared to groups such as platyhelminths and nematodes. Acording with the database of
the Colección Nacional de Helmintos, Instituto de Biología, there are 507 records of acanthocephalans,
representing 52 species allocated to 39 genera. Most of these records correspond to fishes, either marine,
brackish water or freshwater (362), followed by mammals with 48, birds with 30, and amphibians with
22. As a part of an ongoing research project to propose a molecular phylogenetic hypothesis of the
Polymorphidae, an extensive survey has been conducted to collect samples of acanthocephalan parasites
of birds in several localities of seven states of México, ranging from Southeastern (Yucatán, Tabasco)
through Central (Estado de México, Veracruz) to Northwestern México (Nayarit, Sinaloa, Baja California Sur). Birds are one of the host groups where polymorphids are commonly found. So far, 121 individual birds comprising 20 species have been studied for acanthocephalans, and seven species have been
found: Hexaglandula corynosoma as a parasite of Nyctanassa violacea; Polymorphus brevis infecting Ardea
herodias, Egretta thula and Phalacrocorax brasilianus; Polymorphus obtusus as a parasite of Ahythya affinis;
Polymorphus trochus infecting Fulica americana; and Racantha gravida infecting the cormorant Phalacrocorax auritas; Pseudocorynosoma anatarium infecting Bucephala albeola; Pseudocorynosoma constrictum as a
parasite of four species of ducks (Anas spp.), and finally, Southwellina hispida, the most widespread
species that has been found in 11 species of birds, most of them belonging to the Ardeidae. In this study,
we present a comparative morphology of the body surface of these species of acanthocephalans by using
scanning electron microscopy.
410
Key to Nematodes of Freshwater Fishes in México. J.M. CASPETA MANDUJANO*, Universidad
Autónoma del Estado de Morelos, Cuernavaca Morelos, México.
The first reports dealing with nematodes from freshwater fishes in México were published by North
American authors Pearse (1936) and Chitwood (1938), who recorded the presence of a few nematode
234
ABSTRACTS
parasites from cave and cenote fishes from the Peninsula of Yucatán. In the 1970s, new investigations
into the nematode parasites of freshwater and brackish-water fishes were initiated by Caballero (1971)
and followed by Caballero-Deloya (1977), Osorio-Sarabia (1982, 1984), Osorio-Sarabia et al. (1986,
1987), Lamothe-Argumedo et al. (1989), Almeyda-Artigas (1991), Pérez-Ponce de León et al. (1992,
1996), Almeyda-Artigas et al. (1992, 1993), Moravec et al. (1992, 1995a, b, c, d), andrade-Salas et al.
(1994), Lamothe-Argumedo (1996, 1997), Moravec and Vargas-Vázquez (1996), Sánchez-Álvarez et al.
(1998), Caspeta-Mandujano et al. (1999), Moravec et al. (1999a, b), Caspeta-Mandujano et al. (2000a,
b, c, d), Caspeta-Mandujano and Moravec (2000), Moravec et al. (2000a, b), Caspeta-Mandujano et al.
(2001), Choudhury and Pérez-Ponce de León (2001), Caspeta-Mandujano et al. (2002), Moravec et al.
(2002a, b), González-Solís and Moravec (2002), and Moravec and Salgado-Maldonado (2002), MejíaMadrid y Pérez-Ponce (2003), González-Solís y Moravec (2004), Caspeta-Mandujano et al. (2005),
Gopar-Merino et al. (2005), Caspeta-Mandujano et al. (2007a, b). The number of nematodes reported
so far and the relatively high number of new species of nematodes recorded recently from freshwater
fishes create the neccessity of concentrating all this information, enabling their reliable identification on
the basis of the present state of knowledge.
411
Cestodes of the Family Dilepididae from Fish-eating Birds in México. M.P. ORTEGA-OLIVARES*,
Laboratorio de Helmintología, “Dr. Eduardo Caballero y Caballero,” Instituto de Biología, UNAM,
México DF, México, T. SCHOLZ, Institute of Parasitology, Academy of Sciences of Czech Republic,
Ceské Bud jovice, Czech Republic, and G. SALGADO-MALDONADO, Laboratorio de Helmintología,
“Dr. Eduardo Caballero y Caballero,” Instituto de Biología, UNAM, México DF, México.
The Dilepididae (Cyclophillidea) are recovered frequently from birds, especially in fish-eating birds
(herons and egrets). In México, their larvae are very frequent parasites of freshwater fishes. In México,
the publications on the presence of cestodes in piscivorous birds are few and most of the cestodes are
being reported for the first time. Eleven species of fish-eating birds were collected from the six localities
from the Gulf coast of México and twelve species of cestodes were recovered. This presentation shows
the results of the taxonomic studies and morphological descriptions of twelve species of cestodes collected from fish-eating birds from the Gulf coast of México.
412
Spiniloculus (Tetraphyllidea) Diversity in Bamboo Sharks (Orectilobiformes: Hemiscylliidae) of Australia
and Borneo. L. DESJARDINS* and J.N. CAIRA, Department of Ecology and Evolutionary Biology,
University of Connecticut, Storrs CT, USA.
The onchobothriid cestode genus Spiniloculus is poorly known. At present, the genus is monotypic.
Records of its sole species, S. mavensis, are restricted to the type locality of Moreton Bay, Australia, and
are based on limited material. New material consisting of 15 specimens of a new species of Bamboo
shark, Chiloscyllium cf. punctatum, were examined for cestodes from Cairns, Australia, and 12 to 16
specimens of each of Chiloscyllium hasselti, Chiloscyllium indicum and Chiloscyllium punctatum from
Malaysian Borneo were examined. The Australian material yielded two new species of Spiniloculus, both
of which are distinguished readily from S. mavensis in their possession of post-poral testes. Only one of
the Bornean shark species, C. punctatum, was found to host Spiniloculus. This Bamboo shark species,
however, hosted at least four distinct species of Spiniloculus. All four of these species are new to science
and are distinguished easily from S. mavensis in their small size or their possession of post-poral testes.
Two of the species possess post-poral testes, but differ from the two new Australian species in hook size
number of proglottids. All six new species were found to exhibit prevalences and intensities that were
markedly lower than those exhibited by species of their sister genus, Yorkeria, which parasitizes these
same host specimens. This work leads us to believe that the identification of the type host of S. mavensis
as Mustelus sp. (Carcharhiniformes; Triakidae) may erroneous. These new collections have extended the
range of Spiniloculus to include Cairns in Australia and Malaysian Borneo. They also have expanded our
knowledge of the diversity of this genus, suggesting it is much more speciose than currently thought.
235
ABSTRACTS
413
Genetic Differences Between Cysticerci of Taenia solium Isolated from Human Brain and from Pigs.
A.C. HINOJOSA-JUAREZ, Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas,
IPN, México DF, México, G. ZÚÑIGA, Departamento de Zoología, Escuela Nacional de Ciencias
Biológicas, IPN, México DF, México, M. SANDOVAL-BALANZARIO, Servicio de Neurocirugía, Hospital
de Especialidades del Centro Medico Nacional La Raza, México, S. GONZÁLEZ-GUZMÁN, Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, IPN, México DF, México, D.P.
McMANUS, Laboratory of Molecular Parasitology, Queensland Institute of Medical Research, Queensland, Australia, and A. MONROY-OSTRIA*, Departamento de Inmunología, Escuela Nacional de
Ciencias Biológicas, IPN, México DF, México.
In México, neurocysticercosis has an incidence of 0.2–3.4%. High human neurocysticercosis mortality
rates are found in the State of México, situated around México City, comprising both urban areas with a
large human population and rural areas with traditional breeding of pigs that often lack appropriate
hygienic conditions. Mitochondrial COI, ribosomal ITS1, and 28S rDNA DNA from 24 Taenia solium
cysticeri isolates from pigs from several districts in México State and cysticerci (two racemosus type and
11 cellulosae) from patients with neurocysticercosis were amplified by polymerase chain reaction (PCR)
and the amplicons obtained were RFLP analyzed with several restriction enzymes. PCR-RFLP data were
analyzed as restriction fragments, and coded as presence-absence data. The Li-Nei index was used to
build a similarity matrix among different isolates, and used in a Principal Coordinates Analysis (PCoA) in
a multidimensional space to investigate genetic relationships among them. The results show that the
samples studied formed two distinct groups, one comprising the pig isolates and the other the human
brain isolates. The analysis of molecular variance (AMOVA) indicated that these groups were genetically
different, which suggest that these isolates could represent varieties of T. solium.
414
Phylogenetic Relationships of Eimeria (Apicomplexa: Eimeriidae) Parasites from Squirrel Hosts Based on
Plastid ORF 470 DNA Sequences. J. CASEBOLT*, D. HOFMANN, C. MANDICH, C. OLIVER, D.
MOTRIUK-SMITH and R.S. SEVILLE, Department of Zoology and Physiology, Casper College Center,
University of Wyoming, Casper WY, USA.
Previous studies have suggested that the conserved plastid Open Reading Frame (pORF) 470 DNA
sequence is useful for inferring the evolutionary relationships of Apicomplexan parasites. Results suggest
that evolutionary relationships of species of Eimeria are reflected more in the morphology of the sporulated oocyst than host specificity. Six Eimeria species from squirrel hosts were selected for this study:
Eimeria vilasi, Eimeria lateralis and Eimeria morainensis from the Wyoming ground squirrel (Spermophilus
elegans); Eimeria lancasterensis and Eimeria ontarioensis from the fox squirrel (Sciurus niger); and Eimeria
callospermophili from the yellow-bellied marmot (Marmota flaviventris). DNA was isolated and partial
pORF 470 sequences were PCR-amplified, sequenced, and phylogenetic trees generated using PAUP 4.0
maximum parsimony and neighbor joining analyses with Toxoplasma gondii as the outgroup. Sequences
from Genbank for Eimeria reedi and Eimeria langebarteli also were included. Maximum likelihood
pairwise distances between species ranged from 7% (E. langebarteli and E. morainensis to 20% (E.
langebarteli and E. callospermophili). Examination of the phylogenetic trees revealed three clades, two of
which are comprised of species with oocysts lacking an oocyst residuum (OR), E. vilasi and E.
morainensis on one branch and E. lancasterensis and E. vilasi on another. The third group has two species
each with oocysts possessing an OR (E. callospermophili and E. reedi) and interestingly E. lateralis, which
is reported to possess an OR that disappears during sporulation, and Eimeria ontarioensis that does not
possess an OR, but is the only species in the analysis with a micropyle.
415
Parasite Collections of Importance to Tropical Veterinary Medicine at Harvard University’s Museum of
Comparative Zoology. D. CONN, Department of Invertebrate Zoology, Museum of Comparative
Zoology, Harvard University, Cambridge MA, USA.
Harvard University’s Museum of Comparative Zoology (MCZ) maintains many parasite collections.
Among these are collections of many parasites important to tropical veterinary medicine. The most
236
ABSTRACTS
important collections are of avian and mammalian ticks (Acarina) that are important as both parasites
and disease vectors. Nematodes are second in importance, followed by cestodes, trematodes, and several
minor groups of parasitic helminths. Small collections of crustacean parasites of fish and protozoan
parasites also are maintained. The MCZ conducted major expeditions to tropical areas in the early 1900s.
Among these were the Kelley-Roosevelt expedition to Indo-China, Strong’s African onchocerciasis
expedition, Coolidge’s Asiatic Primate Expedition, Natterer’s filariasis expedition to Brazil, the British
Vernay Malaysia Expedition, and Putnam’s Congo expedition. Many were targeted primarily at medical
parasites, but collections of hundreds of veterinary and zoonotic parasites also were made from these and
other expeditions to tropical areas of the South Pacific, Africa, the Caribbean, Central America, and
South America. Hosts for the parasites cover the range of veterinary interest, including companion
animals, major livestock species, laboratory species, gallinaceous and anserine fowl, reptiles and amphibians, exotics/zoo animals, fishes, and wildlife. Specimens are curated either whole in vials, or on microscope slides as whole mounts or histopathological sections. The primary emphasis of MCZ’s current
work is on voucher specimens from epidemiological, experimental, and clinical research. Researchers
from tropical areas around the globe are welcome to submit specimens for deposit. Researchers who are
interested in examining specimens from the MCZ collections are welcome to request a visit to the MCZ
or to request loan of specimens, subject to the museum’s policies posted on our website at http://
www.mcz.
harvard.edu. We are in the process of listing all specimens on our online searchable database, which is
accessible to any interested veterinary researchers or clinicians.
416
Taxonomic Study of the Phyllosoma Complex and Other Triatomine Species (Insecta: Hemiptera:
Reduviidae) of Epidemiological Importance in the Transmission of Chagas Disease: Using ITS-2 and
mtCytB Sequence. F. MARTÍNEZ, G. VILLALOBOS, Departamento de Inmunología, UNAM, México
DF, A. CEVALLOS, Departamento de Biología Molecular y Biotecnología, UNAM, México DF, P. DE LA
TORRE, J.P. LACLETTE, Departamento de Inmunología, UNAM, México DF, R. ALEJANDRE-AGUILAR,
Departamento de Parasitología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional,
and B. ESPINOZA*, Departamento de Inmunología, UNAM, México DF, México.
The subfamily Triatomine includes more than 130 species of insects that feed on blood of vertebrates. In
this group are the vectors that transmit the hemoflagellate protozoan Trypanosoma cruzi, the causal agent
of Chagas disease or American Trypanosomiasis. The phylogenetic relationship between the subfamily
Triatominae has been discussed recently, in particular some complex present in México. The use of
molecular markers has contributed more data to the understanding of the classifications and the phylogenetic and phylogeographic relationships of this important group of vectors in México.The purpose of this
work was to clarify the taxonomy and phylogenetic relationship of the Phyllosoma complex and other
important vectors in México. The present study employed two molecular markers, the cytochrome B
gene (mtCytB) and the internal transcribed spacer 2 (ITS-2), for the phylogenetic analysis of species of
triatomine present in México and southern USA.The following species of triatomine were analyzed:
Triatoma bassolsae, T. longipennis, T. mazzottii, T. mexicana, T. pallidipennis, T. picturata, and T. phyllosoma
belonging to the Phyllosoma complex, as well as T. dimidiata, T. rubida, T. infestans, and Rhodnius prolixus.
The results obtained with the analysis of the ITS-2 sequences showed that the Phyllosoma complex species
could not be separated phylogenetically, since T. bassolsae and T. pallidipennis, as well as T. phyllosoma and
T. mazzottii, were indistinguishable. In contrast, the mtCytB gene separates each one of these triatomine
species. The results support the proximity of all seven species currently included in the Phyllosoma
complex as well as the exclusion of T. dimidiata from this complex. For the first time, T. lecticularia and
T. rubida were analyzed and shown to be related to the Phyllosoma complex.
417
Identification of a Thioester-containing Protein (TEP) from the Malaria Vector Anopheles albimanus. M.
GARRIDO-ARMAS*, Departamento de Patología Experimental, CINVESTAV-IPN, México DF, M.
GONZÁLEZ-LÁZARO, Departamento de Biología Celular, CINVESTAV-IPN, México DF, L. CORTÉSMARTÍNEZ, Departamento de Patología Experimental, CINVESTAV-IPN, México DF, J. MARTÍNEZ237
ABSTRACTS
BARTNECHE, CISEI-INSP, Cuernavaca, Morelos, and F.D. HERNÁNDEZ-HERNÁNDEZ, Departamento de Patología Experimental, CINVESTAV-IPN, México DF, México.
Thioester-containing proteins (TEPs) are present in a large number of organisms such as insects, mollusks, fish, birds and mammals. It is well established that these proteins play an important role in immune responses, either as part of the complement system or as universal protease inhibitors (α 2macroglobulins). In the mosquito Anopheles gambiae, a total of 15 TEP homologues have been identified.
of these, TEP1 has been shown to function as a complement-like opsonin for bacteria, while TEP4 is upregulated in Plasmodium-infected mosquitoes. In order to identify immune-related genes in Anopheles
albimanus—one of the main malaria vectors in México—we sequenced clones from a cDNA library
constructed from mosquitoes challenged with Gram (-) bacteria. Among the screened clones, we found a
sequence with homology to Anopheles gambiae TEP15. Based on this sequence, we designed specific
oligonucleotides to obtain the complete sequence of the mRNA by means of 3r- and 5r- rapid amplification of cDNA ends (RACE) assays. The same oligonucleotides also were used to amplify a 467 bp
fragment of the mRNA to determine gene expression. As a result of the 3r- and 5r- RACE experiments,
we obtained a complete transcript sequence whose size is similar to the one determined by Northern blot
assays, which indicated that the mRNA has an estimated size of 1300–1500 bp. To determine gene
expression patterns, we performed RT-PCR assays to amplify a fragment of the mRNA. We found that
the gene is expressed only in some stages of the life cycle. The gene is expressed in adult female mosquitoes, particularly in the fat body. To establish the possible participation of this TEP in the immune
response of the mosquito, we challenged an Anopheles albimanus cell line with LPS and zymosan (β 1-3
glucan), and found that the gene is expressed under both experimental conditions. Currently, we are
performing RT-PCR assays to determine the expression profile of this gene in female mosquitoes challenged with different bacterial strains.
418
Characterization of a Scavenger Receptor in the Malaria Vector Mosquito Anopheles gambiae. M.
GONZÁLEZ-LÁZARO*, L. FLORES-ROMO, Departamento de Biología Celular, CINVESTAV-IPN,
México DF, M. RODRÍGUEZ, CISEI-INSP, Cuernavaca, Morelos, and F.D. HERNÁNDEZHERNÁNDEZ, Departamento de Patología Experimental, CINVESTAV-IPN, México DF, México.
One of the crucial steps for the activation of the immune response is the discrimination between self and
non-self structures. This process is mediated by pattern recognition receptors (PRRs), which recognize
molecular patterns associated to pathogens (PAMPs) that are present in microorganisms, but absent in
the responding organism. Scavenger receptors (SR) constitute a specific type of PRRs. This family of
receptors is formed by transmembrane glycoproteins that participate in the recognition of polyanionic
ligands, and it has been established that members of the SR family are involved in immunity and developmental processes. In Drosophila melanogaster, two of the best characterized SR are Croquemort and
dSR-CI. Croquemort participates in the recognition of apoptotic cells, while dSR-CI is able to recognize
Gram (+) as well as Gram (-) bacteria. Studies of comparative genomics have established that homologues to both receptors are present in the malaria vector Anopheles gambiae; however, little is known
about them in the mosquito. To further our understanding of these receptors, we looked for their
transcript sequences in the Anopheles gambiae database. Based on the sequence of the mosquito genes for
dSR-CI (ENSANGT00000015204) and one of the Croquemort genes (ENSANGT00000012288), we
designed specific oligonucleotides to amplify a fragment of the mRNA to determine gene expression
patterns. Since both Croquemort and dSR-CI were described initially in the embryonic phases of D.
melanogaster, we first determined the expression profile of these receptors in the different life cycle stages
by RT-PCR assays. A fragment of 453 bp corresponding to the SR-CI transcript was present in all the
stages of the life cycle of the mosquito, but with different band intensities. We also found a fragment of
496 bp corresponding to the Croquemort transcript in all the life cycle stages. In this case, all the bands
had the same intensity. Currently, we are performing RT-PCR assays to determine the expression profile
of these genes in female mosquitoes exposed to different immunological challenges.
419
Triatomine’s Infestation Associated to Individual and Dwelling Factors in Communities of Four States of
México (DGAPA IN205305). M. CABRERA-BRAVO*, G.E. ROJAS-WASTAVINO, M.O. VENCES238
ABSTRACTS
BLANCO, J.S. ROSALES-PIÑA, A.L. FLORES-VILLEGAS, N.D. LUNA-CHAVIRA, G.S. GARCÍA-DE LA
TORRE and P.M.S. SALAZAR-SCHETTINO, Departamento de Microbiología y Parasitología, Facultad de
Medicina, UNAM, México DF, México.
In Chagas disease, the main mechanism of transmission is vectorial. In México, different species exist.
Risk factors individuals and dwellings associated with the infestation of triatomines will allow strategies
for control. We studied communities with intra- and peridomicile vector species using direct interview,
deliberate search of vectors (flushing out method), and blood samples on filter paper and venus puncture
(for confirmation in sera). In Morelos, Triatoma pallidipennis were search 36 dwellings and 106 individuals; in Tamaulipas, Triatoma gerstaeckeri in 97 dwellings and 263 individuals; in San Luis Potosi, Triatoma
dimidiata in 51 dwellings and 187 individuals, and in Queretaro, Triatoma barberi in 46 dwellings and 97
individuals. Construction materials of roof, walls and floor, presence of cracks, regular or bad ventilation
and illumination were risks factors associated with the presence of triatomines in dwellings in the states
of Queretaro and San Luis Potosi. Morelos and Tamaulipas were positively associated only with the
presence of cracks. Regular or bad cleaning of dwellings was associated with infestation in four states.
The presence of animals was associated with the presence of the vectors in three states and was negatively
correlated in Morelos. Although insecticide was utilized, the infestation was positive in three states and
negative in San Luis Potosi. Seroreactivity and the presence of triatomines was associated in the same
dwellings in Queretaro and San Luis Potosi. In Morelos and Tamaulipas, there was no association
between vectors presence and seroreactivity, because both were found in different dwellings. For this
reason, it was observed that dwelling characteristics, inhabitants’ customs and Trypanosoma cruzi seroreactivity participate in the dynamics of Chagas disease transmission in these states. This knowledge must
be considered to carry out interventions for the control, surveillance and prevention of this disease,
including the community participation in activities like cleaning dwellings, health education and insecticide spraying.
420
Evaluation of Cd4+, Cd8+ and Gamma-Delta (G-D) Lymphocytes in the Abomasal Mucosa in Sheep
with High and Low Resistance to Haemonchosis. M.A. MUÑOZ-GUZMÁN, R. DOMÍNGUEZMARTÍNEZ, A. BUENDÍA-JIMÉNEZ and F. ALBA-HURTADO*, Depto. de Ciencias Biológicas, FESCuautitlán, UNAM, México DF, México.
The objective was to establish a relationship between the presence of lymphocytes CD4+, CD8+ and GD in the abomasal mucosa and the abomasal lymph node (ALN) of lambs with the resistance to Haemonchus contortus infection. Two breed groups of male lambs were used, 12 Blackbelly (Bb) and 14
Columbia (CB), with each group divided in two sub-groups (10 experimentals in each group with the
rest as control animals). During the first six weeks, the experimental groups received a weekly individual
inoculum of 1,000 larvae 3 of H. contortus. Egg counts per gram of feces (EGF) were done during 15
weeks, after which the animals were euthanized. Tissue samples were collected from the fundic (FRA)
and pyloric (PRA) regions of the abomasum and ALN. The tissues samples were processed by immunohistochemistry using anti-ovine CD4, anti-ovine CD8 or anti-bovine WC-1 monoclonals (Bethyl).
Counts of in situ-marked lymphocytes were expressed as the number of cells by cm2. The results showed
that the Bb lambs eliminated smaller amount of EGF (p < 0.05) than the Cb lambs (average EGF 124
and 2,402, respectively). The Bb lambs showed a greater number of CD4+ in the PRA (p < 0.05) than
the Cb lambs and control animals (47,700, 19,891 and 15,010, respectively); similarly, in FRA (6,593;
5,049 and 1,223, respectively). The G-D lymphocytes in the PRA also increased (p < 0.05) in the Bb
animals when compared with the Cb and control animals (26,074, 11,594 and 11,910, respectively).
These results point out the importance of CD4+ and G-D cells types in the acquired immunity and its
significance in the resistance to the ovine haemoncosis. (Sponsored by Research Project PAPIIT
IN219005-2 and Program of Doctorate in Sciences of the Production and Health Animal, UNAM.)
421
Abomasum Plasmatic Cells (Ig+-CEL): In situ Evaluation in Sheep with Experimental Haemonchosis.
M.A. MUÑOZ-GUZMÁN*, S.A. HERNÁNDEZ-RIVERA, A.A. AYANEGUI, G. VALDIVIA-ANDA and F.
ALBA-HURTADO, Dpto. de Ciencias Biológicas, Fes-Cuautitlán, UNAM, México DF, México.
239
ABSTRACTS
The objective of this work was to study the relationship between the presence of the Ig+-CEL in the
abomasum mucosa and resistance in sheep with an experimental Haemonchosis. Two breed groups of
male lambs were used: 12 Blackbelly (Bb) and 14 Columbia (Cb), each group divided in two sub-groups
(10 experimentals with the rest as controls). Experimental animals received 6,000 Haemonchus contortus
larvae 3 by trickle infection. During 15 weeks, individual fecal samples were collected and egg counts per
gram of feces (EGF) were done. Animals were euthanized at the end of the experimental period. Samples
from the fundic (FRA) and pyloric (PRA) regions of the abomasum were collected and frozen at -85°C.
Immunofluorohistochemistry was used: tissue samples were processed by cryotomy and incubated with
rabbit-anti-sheep IgA, IgG and IgM (Bethyl, Labs), a Goat-anti-rabbit IgG conjugated with TRITC
(SIGMA Labs) was used as secondary fluorescent antibody. The in situ-marked Ig+-CELs were counted
and expressed as the number of fluorescent cells per field. Bb lambs eliminated a smaller amount (p <
0.05) of EGF than Cb lambs (average EGF 124 and 2,402, respectively). Challenged animals (Bb and
Cb) displayed a higher counts of IgA+-CELs in the FRA and PRA samples when compared with IgG+CELs and IgM+-CELs (p < 0.05). Infected animals within breed groups showed higher IgA+-CEL
counts than the control animals in the group (p < 0.01). No difference in IgG+-CEL counts was
observed between Bb and Cb groups. The correlation between Ig+-CELs counts and the EGF ranged
from -0.03 to 0.61 and was not significant. Data suggested that the Ig+-CELs were associated with the
infection, but not with resistance in sheep Haemonchosis. (Sponsored by UNAM research project
PAPIIT 219005-2.)
422
Identification of New Leishmania Vaccine Candidates by Bioinformatic Analysis of Leishmania major
Genome and in vivo Validation. C. NAJERA-HERRERA*, R. PIÑA-AGUILAR, F. XACUR-GARCIA, M.J.
RAMIREZ-SIERRA and E. DUMONTEIL, Laboratorio de Parasitologia, CIR, Universidad Autónoma de
Yucatán, Mérida, Yucatán, México.
Leishmaniasis is a worldwide disease with an estimated 12 millon people infected and 350 millon people
at risk. The recent completion of sequencing of Leishmania major genome, together with bioinformatic
tools, open opportunities for the rational development of vaccines and identification of antigens. The
objective of this work was to identify new vaccine candidates by bioinformatic analysis of the L. major
genome and validate in vivo their immunogenicity. Eight thousand, two hundred seventy-two translated
sequences from the annotated L. major Friedlin genome were analyzed with RANKPEP epitope prediction algorithm to predict MHC class I mouse epitopes (H2-Kd and H2-Dd alleles). A total of 627 genes
containing epitopes with MHC binding scores of more than 85% were reanalyzed with additional
epitope prediction programs to established consensus predictions, using five distinct algorithms for H2Dd and 8 for H2-Kd. Seventy-nine genes were identified with top consensus predictions (4/5 or 8/8 for
H2-Dd and H2-Kd, respectively), most encoding for hypothetical proteins (64/79); only 15/79 had a
putative function. Peptides corresponding to the top 26 predicted epitopes were used to immunize
BALB/c mice, and their immunogenicity was evaluated by measuring peptide-specific IFNgamma
production by flow cytometry and cytokine ELISA assays. At least 11/26 peptides induced a high
IFNgamma production from CD8+ T cells. T cells from immunized or infected mice also responded to
soluble Leishmania mexicana antigen and/or peptide stimulation, confirming the annotation of the
corresponding genes, and a significant level of conservation between Leishmania species for some of the
antigens. These epitopes and genes represent new candidates for vaccine development against Leishmania.
423
Kinetics of the Immune Response in the Intestinal Mucosa of Hamsters Infected with Taenia solium
Adults. G. AVILA-RAMIREZ*, L. AGUILAR-VEGA, S. VELASCO-VELASCO, Facultad de Medicina,
UNAM, México DF, F.J. GARCIA-VAZQUEZ, Instituto Nacional de Pediatria, SSA, México DF, E.
FARFAN, Instituto Nacional de Pediatria, SSA, México DF, and A. FLISSER, Facultad de Medicina,
UNAM, México DF, México.
When Taenia solium grows in normal hamsters, mature, but not gravid worms are obtained. Expulsion
starts at three weeks and the parasites may remain up to two months. An inflammatory reaction in the
intestinal mucosa, surrounding the scolex of the worm, is produced; it is comprised of lymphocytes,
240
ABSTRACTS
plasma cells, eosinophils and goblet cells. Currently, we are searching for mRNA of Th1 and Th2 interleukins by in situ hybridization in intestinal biopsies. For this, hamsters were infected per os with eight T.
solium cysticerci, with necropsies done at different days post-infection (dpi). One cm biopsies of the small
intestine were taken from the area surrounding the scolex of all tapeworms found, fixed in PBS-paraformaldehyde and processed for histology; 3 µm sections were obtained and adhered to electrocharged
slides. Antisense probes for the detection of IFNγ, IL-4, IL-5 and IL-13 mRNA were constructed,
according to published literature. In situ hybridization was performed with digoxigenin labeled oligonucleotides; α-tubuline was used as a positive control and human papiloma virus as a negative control.
Immunological detection was obtained with antibodies against digoxigenin coupled to alkaline phosphatase or peroxidase. Kinetics of each cytokine was defined by counting the number of positive cells per
100 enterocytes at different dpi. IFNγ and IL-13 were detected in 67% of infected hamsters at 2 dpi, IL4 at 4 dpi in 33%, at 8 dpi all hamsters were positive for IL-4 and IL-13, 50% for IFN-γ and IL-5 began
to be detected in 33%. At 16 dpi, no positive reaction for IFN-γ was observed, while the other cytokines
were positive. Eosinophils were counted in each villous, an increase was observed since 8 dpi, the highest
counts were at 20 dpi, which coincide with IL-5 increase. These data suggest that tapeworm expulsion is
mediated by a Th2 response, with the participation of eosinophils and their mediators, but is not mediated by IFNγ, since expulsion takes place after 21 dpi.
424
HSP60 E. coli Participate in the Expression of Human Beta Defensin 2 in Peripheral Blood Mononuclear Cells (PBMC). M.D. HERNÁNDEZ-CÓRDOVA*, Immunology Department, ENC-IPN, México
DF, M.L. DOMÍNGUEZ-LÓPEZ and M.E. CANCINO-DÍAZ, Immunology Department, ENC-IPN,
México DF, México.
Antimicrobial peptides are key effector molecules of the innate immune response. Generally, they have a
positive charge and amphipathic properties. These peptides are secreted mainly by epithelial cells,
neutrophils and macrophages. The main role of antimicrobial peptides is the direct lysis of microbes.
These peptides also have chemotactic properties, which may modulate the immune response, serving as a
bridge between the innate and adaptive immune responses. In humans, these antimicrobial peptides have
been identified and include salivary histatins, lactoferricin, six α-defensins, two β-defensins (HBD), and
an 18-kD human cationic antimicrobial protein, hCAP18. Heat shock proteins (HSP) are among the
most highly conserved molecules of the biosphere. They protect prokaryotic or eukaryotic cells from
various insults during periods of stress. It seems that HSP become important antigens during infection
and inflammation and in this way influence and sustain anti-infectious and autoimmune responses. The
aim of our study was to evaluate whether the HSP60 E. coli (HSP60 Ec) is able to induce the antimicrobial peptides expression in PBMC. From five healthy donors, we obtained the PBMC by density gradient; 2 x 106 cells were incubated at 37°C after the addition of different HSP60E concentrations, optimized earlier. After 24 h of stimulation, the cells were pelleted and collected. Subsequently, total RNA
was isolated with TRIzol. The HBD-2 expression was evaluated with RT-PCR. Our results shown that,
in a dose-dependent way, the HSP60Ec induces the expression of the HBD-2 in PBMC. In this way, we
demonstrated that antimicrobial peptides are able to respond to both complete bacterial structures and
antigen-specific stimulus. Thus, not only with the HBD-2 chemiotactic activity, the role of these biomolecules in the adaptive immunity is explained; moreover, with the acquired antigen-specific responses
observed in this study. Therefore, our findings suggest a possible role of HSP60 Ec as modulator of the
expression of PBMC antimicrobial peptides.
425
Albendazole’s Effects on Recognition of a Trichinella spiralis Newborn Larvae’s 49 kDa Antigen. R.A.
AVENDAÑO-RABIELLA*, M.R. SALINAS-TOBON, Immunology Department, ENCB-IPN, México DF,
and J. HERNÁNDEZ, Department of Genetic and Molecular Biology, CINVESTAV-IPN, México DF,
México.
The most frequently used drugs in the treatment of diverse intestinal illness produced by helminths are
the derivatives of Benzimidazol, which commonly are indicated for the treatment of human trichinellosis.
It has been shown in infected mice with the parasite Trichinella spiralis that mebendazol inhibits parasite
secretions and induces changes in Trichinella spiralis-infected muscle cells, such as the disappearance and
241
ABSTRACTS
lack of parasitic products. The polyclonal antibody reactivity against antigens of the three stages showed
that the 49 kDa protein is not on the surface and is shared between both adult and newborn larvae. This
component characterization will determine the function of the 49kDa protein in the host–parasite
interaction. The results of different studies, however, have caused much controversy about the efficiency
of the benzimidazol derivates in the treatment of the extraintestinal phase and its consequences in the
diagnosis, which is why we used albendazol in this study. In this way, albendazol will be an important
tool in the characterization of the 49 kDa antigen of the newborn larvae, in that it offers perspectives for
understanding the mechanisms developed by this parasite in its course of establishing itself in muscular
or intestinal tissues. The results of this study, provided by ELISA and electrophoretic assays, were the
production of antibodies against antigens from newborn larvae determined in different periods of
treatment (3 and 6 days of treatment).The general trend in antibody production depicted by ELISA
assays was different, where kinetics of antibody with a treatment of six days of albendazole was diminished to three days. These results also were supported by electrophoretic assay.
426
Pilot Clinical Trial of a Therapeutic DNA Vaccine Against Trypanosoma cruzi Infection in Dogs. I.
QUIJANO-HERNÁNDEZ*, Laboratorio de Parasitología, CIR, Universidad Autónoma de Yucatán,
Mérida, Yucatán, M. BOLIO-GONZÁLEZ, J. RODRÍGUEZ-BUENFIL, Facultad de Medicina Veterinaria
y Zootecnia, Universidad Autónoma de Yucatán, Mérida, Yucatán, M.J. RAMIREZ-SIERRA and E.
DUMONTEIL, Laboratorio de Parasitología, CIR, Universidad Autónoma de Yucatán, Mérida, Yucatán,
México.
Chagas disease is an important health problem in most Latin American countries, and a concern in dog
populations, which act as a reservoir. We showed in previous studies that a therapeutic DNA vaccine
could partially control the disease following Trypanosoma cruzi infection in mice, so that this vaccine may
represent an alternative treatment for Chagas disease. Here we further evaluated the therapeutic efficacy
of this vaccine in experimentally infected dogs during the acute phase. Eight naïve dogs were infected
with of 50,000 blood trypomastigotes/kg via intraperitoneal, and treated at days 15 and 30 post-infection with 500 µg of plasmids encoding T. cruzi antigens TSA-1 and Tc24 with aluminum phosphate as
adjuvant, or a control plasmid vector, via intramuscular. Follow-up of infected dogs for up to two
months indicated that there was no effect of vaccine treatment on parasitemia. Arrhythmias also were
detected in both groups of dogs starting after four weeks of infection, but control dogs had more severe
and frequent arrhythmias than treated ones. Vaccine treated dogs also presented lower IgG levels compared to control animals, suggesting a cellular rather than a humoral immune response. This was confirmed by the observation of an intense inflammatory reaction in the heart. These partial results suggest
that DNA vaccine treatment may delay Chagas disease progression in T. cruzi infected dogs, and confirm
the potential of this novel treatment.
427
Effect of Albendazol on Antibody Response and Establishment of Trichinella spiralis Muscle Larvae in
Infected Rats. F. VELASCO-RIVERA, R.A. AVENDAÑO-RABIELLA, Departamento de Inmunologia,
Escuela Nacional de Ciencias Biologicas, IPN, México DF, J. HERNÁNDEZ-SÁNCHEZ, Departamento
de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados, IPN, México DF,
and M.R. SALINAS-TOBON*, Departamento de Inmunología, Escuela Nacional de Ciencias Biologicas,
IPN, México DF, México.
Systematic studies to assess the treatment efficacy of trichinellosis with albendazol (ABZ) using an
appropriate serological method are scarce. To this aim, we analyzed the effect of ABZ during the larvae
encapsulation phase on the whole antibody (Ab) response and on muscle larvae (ML) establishment and
infectivity. Four rat groups were infected with 2,000 Trichinella spiralis ML. Rats were treated with
vehicle (B) or ABZ, 20 mg/Kg/day for 3 (C) or 6 (D) days starting on day 13 post-infection (pi). Serum
samples collected before and at different times after the infection were analyzed by ELISA using newborn larvae total soluble antigen (NBL), ML excretory-secretory products (MLES) or ML total soluble
antigen (MLT). ML recovery was done at day 61 pi to determine ML establishment and viability as well
as the infectivity in mice. In control rats not treated with ABZ, the Ab response against NBL and MLT
antigens and MLES appeared on days 10 and 14 pi, respectively. An early production of Abs to NBL and
242
ABSTRACTS
MLT peaked on day 14 pi. The highest antibody production to NBL, MLT and MLES antigens was on
days 14, 31 and 61, respectively. Group B showed similar results as group A. Compared with groups A
and B, in group C, a transitory decrease of the Ab response to NBL antigen was observed from days 17
to 26 and to MLES antigens from days 14 to 26, while Ab production to MLT was not affected. In
group D, decreasing Ab levels against NBL and MLES were more evident. Unlike the infectivity, ML
establishment in treated rats and viability of recovered ML from group C were not affected by the 3-day
ABZ treatment; only 1% of the ML recovered established the infection in the mouse. ML establishment
also was affected by the 6-day ABZ treatment. Altogether, these results suggest that a not-yet-defined
antigen(s) in NBL and MLT are candidates for early diagnosis of trichinellosis, while NBL and MLES
antigens may be useful to evaluate ABZ treatment efficacy.
428
Susceptibility of Criollo and Suffolk Lambs to Haemonchus contortus after an Experimental Inoculation.
E. ROMERO-ESCOBEDO*, Departamento de Ciencias Biológicas, FES-Cuautitlán UNAM, Cuautitlán
Izcalli, Edo. de México, G. TORRES-HERNÁNDEZ, Colegio de Postgraduados, Montecillo, Edo. de
México, F. ALBA-HURTADO, Departamento de Ciencias Biológicas, FES-Cuautitlán UNAM, Cuautitlán
Izcalli, Edo. de México, C.M. BECERRIL-PÉREZ, Colegio de Postgraduados, Montecillo, Edo. de
México, M.A. MUÑOZ-GUZMÁN, Departamento de Ciencias Biológicas, FES-Cuautitlán, UNAM,
Cuautitlán Izcalli, Edo. de México, and J. SOLÍS-RAMÍREZ, Universidad Autónoma Chapingo,
Chapingo, Edo. de México, México.
The use of resistant animals to gastrointestinal parasites (gip) represents a strategy to control parasitism
in sheep, thus trying to avoid the use of many chemical substances. Genetic variation between and within
breeds as an answer to this problem has been documented previously. An experiment was carried out at
Experimental Farm of University of Chapingo, for which 20 Criollo (Local) and 15 Suffolk lambs were
utilized during 20 weeks to determine differences to parasite burdens when they were inoculated experimentally with Haemonchus contortus. Lambs were distributed into four treatments: (a) 15 inoculated
Criollo (IC), (b) five control Criollo (CC), (c) 10 inoculated Suffolk (IS), and (d) five control Suffolk
(CS). Inoculated lambs were given 6,000 infective larvae (L3) of H. contortus. The response variables
were eggs per gram of faeces (EPG), haematocrit (H) and average body weight (BW). The statistical
design was a split-plot in a 2 x 2 factorial design with repeated measures, including lamb genotype (G)
and inoculation (I) as fixed effects, and the lamb as a random effect, plus the effect of a week (W) as a
time factor. Before the statistical analysis was performed, EPG was transformed to [Ln (EPG+1)] to
approximate a normal distribution. Results showed that G, I and W, plus the interaction IxW had a
significant effect (P < 0.01) on both [Ln (EPG + 1)] and BW; means for [Ln (EPG + 1)], according to
G, were 4247 ± 2362, 64.7 ± 157, 6218 ± 3868, and 77.1 ± 179 for IC, CC, IS and CS, respectively.
According to inoculation, those means were 5,036.19 ± 3,858.9 and 70.95 ± 168.77 for inoculated and
non-inoculated lambs, respectively. There was a general tendency for BW to increase in time (week).
Means for BW and H, according to G, were 32.4 ± 6.5 kg and 35.7 ± 5.1; 39.6 ± 8.6 kg and 39.8 ±
2.2; 54.5 ± 5.8 kg and 35.4 ± 5.6; 57.4 ± 9.7 kg and 40.5 ± 2.9, for IC, CC, IS, and CS, respectively.
Criollo represents an alternative to improve raditional flocks in areas where it is difficult and expensive to
apply antihelmintics. (Sponsored by Program of Doctorate in Sciences of the Production and Health
Animal UNAM.)
429
Analysis of Variability of Clones of Trypanosoma cruzi Derived from Mexican Strains by Behavior in
Mice and Culture Cells. M.A. BECERRIL-FLORES*, Área Académica de Medicina, Instituto de Ciencias
de la Salud, Universidad Autónoma del Estado de Hidalgo, Pachuca de Soto, Hidalgo, and P.M.S.
SALAZAR-SCHETTINO, Departamento de Microbiología y Parasitología, Facultad de Medicina,
UNAM, Cd. Universitaria, México DF, México.
In order to better understand the biological heterogeneity of behavior of T. cruzi strains isolated from
México and to explain the variable clinical outcome of Chagas disease, six strains of T. cruzi were cloned
by the Miles’ method (drops of suspension with parasites were diluted in PBS and inoculated to mice).
Virulence and infectivity of 10 or 11 clones derived from each strain were determined in female Balb/c
mice and Vero culture cells, respectively. Variability of clones was determined by Tukey F statistic test.
243
ABSTRACTS
Only one strain, named T5, showed interclonal variability and its clones were subcloned by the same
method; they showed similar behavior to their parental clones. Clones increased the virulence or had the
same behavior after one year of maintaining in mice, but seven clones were eliminated and the virulence
of the four remaining clones was attenuated when they were maintained in LIT axenic culture along one
year. The study demonstrated that there are strains either monoclonal or multiclonal strains of T. cruzi in
México, and the clones could be eliminated or selected by the environment along time; therefore, it is
necessary that strains of T. cruzi have to be cloned prior to characterization.
430
Spleen Cell Proliferation During and After Skin Myiasis by Human Bot Fly Dermatobia hominis
(Diptera: Oestridae). A.C. LEITE*, J.G. GONÇALVES, Departamenteo de Parasitologia, N.M.
BREYNEES, V.C. FERNANDES and A.M. GOES, Departamenteo de Bioquímica e Imunologia, Instituto
de Ciências Biológicas, da Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brasil.
Obligatory cutaneous myiasis by Dermatobia hominis (L. Jr.) is an endemic zoonosis of the Neotropics,
occurring from México to Argentina. Myiasis is medically important and is responsible for great economic losses to livestock production. Using a laboratory mouse model, spleen cells were examined at 5,
10, 15, 20 and 25 days post-infestation (dpi) with D.hominis and at 5, 10, 15, 30 and 60 days postemergence (dpe). Cell proliferation assays were carried out with the following substances: RPMI-1640
medium (Sigma), Canavalia ensiformis (Con A) and secretory–excretory larval product (SELP) of warbles
at 5, 10, 15, 20 and 25 dpi. In mice, the first and second moulds of D. hominis occurred at 5 and 15 dpi,
respectively, with larvae emerging from the host at 30 dpi. Statistically significant differences were seen in
the numbers of spleen cells when each group of mice was compared against all the substances (together),
with values increasing in the following order: 25, 10, 5, 20 and control (0 dpi). When each group of
mice was tested against each substance, significance was seen only for 25 dpi, with values increasing in
the following order: 10-, 25-, 5-SELP, Con A and RPMI. Values for each dpi group versus all the
substances (together) increased in the following order: 30, 10, 15, 60, 5, control. Significant results also
were observed when each substance was tested against mice at each dpi or dpe (not explained in this
abstract). Each dpe group versus each substance produced significance only for 10 dpe, with values
increasing in the following order: Con A, 5, 20, 25, 10, 15 and RPMI. Comparative tests also were
carried out between groups to refine certain observations. During the period of myiasis, there was a
depletion of spleen cells in the mice, particularly under the effect of the SELP at 10 and 15 dpi (L2 and
early L3). By contrast, the number of spleen cells tended to increase up to 60 dpe. Currently, we are
developing new molecular approaches to provide information on SELP of D. hominis and its role in the
insect–host relationship. (Work partially supported by FAPEMIG and CNPq.)
431
The Diagnosis of Porcine and Bovine Cysticercosis by Ultrasonography. A. SCHUNEMANN-DE ALUJA*,
S.C. HERRERA-GARCÍA, Department of Pathology, School of Veterinary Medicine, National Autonomous University of México, R.E. MÉNDEZ-AGUILAR, Clinical of Pets, School of Veterinary Medicine,
National Autonomous University of México, and E.L. SCIUTTO, Institute of Biomedical Research,
National Autonomous University of México, México.
Teniasis–Cysticercosis continues to be a serious problem in many regions of México and other developing
countries. This zoonosis has economic, sanitary and human health implications. One of the problems for
the control of the disease is deficient diagnosis of cysticercosis in pigs and cattle. Ultrasound is a noninvasive and highly sensitive method of observing muscular cysticerci in infected pigs and cattle. The
equipment used was: Logiq Book XP, General Electric with a multifrequency microconvex transducer 411 MHz, and Logiq 5 Expert General Electric with a multifrequency lineal transducer 5-12 MHz.
Seventeen pigs diagnosed as cysticercotic by tongue inspection were examined, and 10 of them were
confirmed with ultrasound and necropsy, with the remaining seven confirmed as negative by the same
methods. A calf was inoculated with Taenia saginata eggs. Ultrasound examination was done at 33, 54,
90, 105 and 145 days post-infection. At 54 days, anecoic (vesicular) cysticerci with an ecogenic structure, corresponding to the scolex, were seen in the ultrasonographic image and were confirmed at 90
days. At 105 and 145 days, the cysticerci were ecogenic. All findings were confirmed at necropsy. The
ecogenic image corresponds to caseous cysticerci, which had formed in the calf 145 days after experimen244
ABSTRACTS
tal inoculation. It is concluded that ultrasonography detects cysticerci at different stages of development
in pigs and cattle.
432
Parasitic Lungworms Associated with Histopathological Lesion in Naturally Infected Sheep. B. COYOTE-CAMACHO*, M.U. ALONSO-FRESAN, Centro de Investigación y Estudios Avanzados en Salud
Animal, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma del Estado de México,
M.E. LÓPEZ-ARELLANO, Centro Nacional de Investigaciones Disciplinarias en Parasitología Veterinaria, R. MONTES-DE-OCA-JIMÉNEZ, Centro de Investigación y Estudios Avanzados en Salud Animal,
Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma del Estado de México, and E.
LIEBANO-HERNÁNDEZ, Centro Nacional de Investigaciones Disciplianrias en Parasitología Veterinaria,
México.
This study was carried out to identify the main pulmonary parasitic nematodes associated with histiopathological lesions observed in naturally infected sheep in a temparate climate. Twenty-one native sheep
from 12- to 18-month-old were used. Sera and faecal samples were taken to recognize the host immuneresponse and to identify the main infective pulmonary larvae (L3) during the winter season in Estado de
México district of México. All the experimental sheep were slaughtered at the end of the winter season
and pulmonary tissue samples were taken to be analyzed by parasitic, pathology and immune techniques.
The results showed that more than 50% of experimental sheep were positive to Dictyocaulus filaria and
Muellerius capillaris, and 12.5% were positive to Protostrongylus spp. At necropsy, severe macroscopy
lesions with a white-yellow and grey colour on the posterior lobule were infected with adult and immature stages of D.filaria; however, no adult stages of Muellerius and Protostrongylus were found. Extensive
secreted mucus was observed, which was collected to determine the level of IgG and γINF by indirect
immunoassays using adult stages of D. filaria antigen. On the other hand, microscopy lesions showed
severe infiltration of mononuclear cell, increased thickness of the interlobular septum, lymphocyte
hyperplasia and damage around the main blood vessels. Infiltrations of macrophages, eosinophils and
master cells were observed together with an increased level of IgG and γINF. For immunofluorescence
labelling of γ δT and CD4+ mainly were observed. Most of the pathological damage in adult sheep
appears to be associated with the presence of D. filaria localized in the pulmonary parenchyma. Although
Muellerius and Protostrongylus adult stages were not found, there is a possibility that they might be
involved in the main pulmonary disease in sheep caused by parasites. Some work has been done with
lungworm in sheep, and it is important to consider them as a strong problem.
433
Participation of Sexual Hormones During Experimental Amebic Liver Abscess in Hamster. C.
CERVANTES-REBOLLEDO*, Department of Immunology, Instituto de Investigaciones Biomédicas,
UNAM, México DF, C.A. ORTÍZ-MARTÍNEZ, Department of Experimental Medicine, Facultad de
Medicina, UNAM, México DF, M. NEQUIZ, Department of Experimental Medicine, Facultad de
Medicina, UNAM, México DF, J.P. LACLETTE, Department of Immunology, Instituto de Investigaciones
Biomédicas, UNAM, México DF, and J.C. CARRERO-SÁNCHEZ, Department of Immunology, Instituto
de Investigaciones Biomédicas, UNAM, México DF, México.
In the infections caused by Entamoeba histolytica, epidemic data suggest an influence of the sexual
hormones in the development of the infection. Symptomatic intestinal amebiasis is reported to be more
common in children and elder people than in adults, and among adults, it is more common in men than
in women. In contrast, the amebic liver abscess (ALA) is more common in adults than in children, and
among adults, this disease greatly predominates in males. Since these variations in the susceptibility
associated with sex and/or age are characterized by hormonal differences and/or changes, it is probable
that the sexual hormones are responsible for the differences observed in the susceptibility to the amebic
infection. In this sense, sexual dimorphism was reported recently during the development ALA in
C57BL/6 mice, associated with differences in the cytokines production that regulates the immune
response to the infection. In this work, the participation of the sexual hormones in the development of
ALA in male and females hamsters was evaluated. The induction of hormonal deficiencies by gonadectomy in male and females hamsters from six to nine weeks old, 15 days before the intraportal infection
with 5 x 105 virulent trophozoites, showed statistically significant differences (p < 0.05) in the weight of
245
ABSTRACTS
the livers of the castrated and infected animals with regard to the uncastrated and infected controls.
Histological examination of liver sections showed scarce inflammatory infiltration and trophozoites
number in the castrated and infected animals compared to the infection controls. Low proliferation of
splenocytes to concanavalin A and amebic antigen in the castrated and infected hamsters was observed
also, probably associated with the absence of testosterone in males and estradiol in females. In conclusion, the results showed that the deficiency of sexual hormones in ALA diminishes the celular immune
response and the damage caused by E. histolytica, suggesting that the interactions between the immune
and endocrine systems play a fundamental role in the establishment, development and outcome of the
amebic extraintestinal infection in hamsters.
434
In vitro Interactions of Neoparamoeba pemaquidensis with Fish and Shellfish Cell Cultures. L.E. LEE,
Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, Canada.
Neoparamoeba pemaquidensis is a ubiquitous marine amoeba that under certain conditions has been shown
to cause disease in several species of fish and shellfish. Most notably, under warm water temperatures, N.
pemaquidensis has been shown to cause amoebic gill disease in various finfish species and implicated as
the causative agent for several diseases in commercially important crustaceans such as lobsters and crabs.
The mechanisms by which N. pemaquidensis ‘home’ into target tissue and cause disease is not known.
Using fish cell lines and shellfish cell cultures as model systems, the present work evaluates physicochemical factors on mechanisms of N. pemaquidensis pathogenicity. Physical factors such as pH, temperature
and osmolarity were evaluated for optimal parasite–cell interactions, while fibronectins and integrins
were evaluated for their role on pathogen–cell adhesion mechanisms. Marine fish and salt water adapted
trout cell lines, and crab and lobster cell cultures were evaluated and compared for their ability to support
growth of the protozoan pathogen and to study cell-pathogen interactions. Cell cultures are powerful
tools by which knowledge about mammalian host–parasite interactions have been acquired and viral,
bacterial or protozoan diseases are diagnosed, but they are almost completely lacking for crustaceans and
comparatively few are available for fish. The fish and shellfish cell culture approach could be essential for
understanding and containing current and emerging marine protozoan diseases.
435
Lymphoma Developed in an Immune Mouse with Burkitt Histopathology Features after Repeated
Infections by Plasmodium yoelii yoelii. F. MALAGÓN*, Departamento de Microbiología y Parasitología,
Facultad de Medicina, UNAM, Cd. Universitaria, México DF, J. GONZÁLEZ, Facultad de Estudios
Superiores de Iztacala, UNAM, Los Reyes Iztacala Edo. de México, O. CASTILLO and E. CARRASCO,
Departamento de Microbiología y Parasitología, Facultad de Medicina, UNAM, Cd. Universitaria,
México DF, México.
In 1958, Denis Burkitt described a B-cell lymphoma in African children associated to malaria by Plasmodium falciparum and Epstein Barr virus infections. Endemic Burkitt lymphoma is present in holoendemic
areas of malaria south of the Sahara, where transmission is intense and chronic. Constant antigenic
stimulation produced by repeated infections is possibly a pathogenic component. Tumors with the
histologic and phenotypic features of Burkitt lymphoma have never been described in mice until January
2007, when Kovalchuk and his colleagues reported lymphomas with striking histological similarities to
Burkitt lymphomas, developing in transgenic mice bearing a mutated human MYC gene. Burkitt type
lymphomas in non-humanized mice submitted to natural murine malaria infections have never been
observed. In our experience, when mice naturally resist a lethal infection by P. yoelii yoelii, they become
immune and, if these immune animals are repeatedly reinfected, they eventually develop different types
of benign and malign tumors. Although no Burkitt lymphoma type was observed previously, in our last
experience a typical starry sky, as seen in the human Burkitt lymphoma histology, was observed in an
immune mouse after several challenges with P. yoelii yoelii. Details of the experiment will be discussed.
436
Dehydroepiandrosterone Inhibits the Establishment, Growth and Reproduction of the Metacestode
Stage of Taenia crassiceps. J.A. VARGAS-VILLAVICENCIO* and J. MORALES-MONTOR, Departamento
de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
246
ABSTRACTS
During the experimental infection with T. crassiceps, there exists a relationship between the immune, the
endocrine and the nervous systems with the parasite. We know that estrogens and progesterone play an
important role promoting the establishment and reproduction of the parasite, whereas androgens, like
testosterone or dyhidrotestosterone, suppress the development of the infection. Nevertheless, the effects
of adrenal steroids during the parasite infection are unknown. The aim of this work was to explore the
effect of the adrenal androgen, dehydroepiandrosterone (DHEA), in the establishment and reproduction
of Taenia crassiceps, both in vitro and in vivo. Administration of DHEA into mice of both sexes produced a
50% reduction in parasite loads. This protective effect was associated in both sexes with an increase in
the mRNA levels of IL-2 (a cytokine associated to protection against cysticerci). Interestingly, INF-γ
expression levels were unchanged after treatment with DHEA. IL-4 showed over-expression in all
treatments (control, infected, infected and treated with DHEA) in contrast with IL-10, which showed
down-expression. Treatment with DHEA diminished IL-6 expression on female mice by three-fold, with
no effect on male mice. In both sexes, DHEA treatment increased androgen receptor expression in spleen
tissue. In vitro treatment of T. crassiceps with DHEA reduced reproduction and motility. Present results
point to DHEA treatment as a new therapeutic possibility to treat cysticercosis, since it can act at both
ends of the host–parasite relationship: increasing the cellular immune response protective against the
parasite and affecting directly the parasite´s reproduction and survival.
437
Sex-steroids Accelerate Evagination of the Scolex in the Human Parasite Taenia solium: Implications to
the Host–Parasite Relationship. G. ESCOBEDO*, C. LARRALDE and J. MORALES-MONTOR, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
The metacestode stage of the tapeworm Taenia solium causes porcine cysticercosis and human neurocysticercosis, both serious veterinary and health problems in third-world countries. Neurocysticercosis
also is considered an emergent health problem in developed countries. In this study, Taenia solium
cysticerci were in vitro exposed to different concentrations of progesterone (P4) and 17-b estradiol (E2).
There was a time- and dose-dependent stimulation effect on scolex evagination and growth. To determine the possible molecular mechanisms by which P4 and E2 affected Taenia solium, pharmacological
experiments using RU-486 (anti-progesterone) and Tamoxifen (anti-estradiol) were performed, as well
as sex-steroid receptors amplification by RT-PCR and detection by Western blotting. Both anti-hormone
treatments blocked the stimulated effect of P4 and E2 on Taenia solium cysticerci scolex evagination.
Concomitantly, cysticerci expressed mRNA for both a and b subtypes of estrogen receptors and A and B
isoforms of progesterone receptor, as well as their proteins. None of these receptors were up or downregulated by steroid treatment. Present results suggest sex-steroids act directly upon Taenia solium
metacestodes differentiation, possibly by binding to a classic and specific parasite steroid receptor, which
also may be involved in their ability to grow faster in castrated or gestant pigs, having serious implications on their host–parasite relationship at molecular and evolutionary levels.
438
In vitro Direct Effects of Insulin on Taenia crassiceps and Taenia solium: Another Molecular Mechanism
Mediating the Host–Parasite Crosstalk. G. ESCOBEDO*, Departamento de Inmunología, Instituto de
Investigaciones Biomédicas, UNAM, México DF, México, M.C. ROMANO, Departamento de Fisiología, Biofísica y Neurociencias, CINVESTAV, México DF, and J. MORALES-MONTOR, Departamento
de Inmunología, Instituto de Investigaciones Biomédicas, UNAM, México DF, México.
Insulin is a growth factor that has a wide spectrum of action on practically all eukaryotic cells. Its action
mechanism includes activation of the insulin receptor and, therefore, phosphatidyl inositol-3 kinase
signaling pathway (PI-3). More recently, insulin receptor and PI-3 have been reported in several parasites
such as trematodes and helminths. Nevertheless, insulin effects upon parasites and their implications to
the host–parasite relationship have been scarcely studied. Here, we describe insulin influences on T.
crassiceps and T. solium metacestodes, causal agents of murine cysticercosis and human neurocysticercosis,
respectively. In vitro culture of T. crassiceps and T. solium were designed to test the possible insulin effects
on those parasites. After five days of insulin treatment, T. crassiceps cysticerci increased two-fold times
their number of buds with respect to control groups, while in T. solium insulin-treated metacestodes,
there was a 100% of evagination. The insulin effects on both parasites were dose-dependent, having
247
ABSTRACTS
positive influences on their metabolic activity and viability. Moreover, insulin treatment caused an
increase size average of both T. crassiceps and T. solium, 2.5 and 1.5 fold-times, respectively. In addition,
by means of RT-PCR and western blot, we also were able to detect the corresponding bands to insulin
receptor in both Taenia species. These results, though preliminary, may help to gain a better understanding of the host–parasite relationship, focusing on the crosstalk between host hormones and parasite
receptors as chemical messengers, evaluating their possible role on vaccines and anti-cysticercotic drugs
development.
439
Differences in Gastrointestinal Parasites Between Two Goat Genotypes in the Dry Tropic of México. D.
CAMPS MOTA*, Ganadería, Colegio de Postgraduados, Texcoco, Estado de México, R.D. MARTÍNEZ
ROJERO, Zootecnia, Colegio Superior Agropecuario del Estado de Guerrero, Iguala, Guerrero, G.
TORRES-HERNÁNDEZ, Ganadería, Colegio de Postgraduados, Texcoco, Estado de México, E.
ROMERO CALLEJAS, Parasitología, UNAM, México DF, C.M. BECERRIL PÉREZ, Ganadería, Colegio de
Postgrad-uados, Texcoco, Estado de México, and J.C. GARCÍA CARRANZA, Zootecnia, Colegio
Superior Agropecuario del Estado de Guerrero, Iguala, Guerrero, México.
Gastrointestinal parasites (gip) directly affect health and productivity of goats. Use of gip-resistant breeds
of goats is an alternative to prevent an indiscriminate use of drugs. A eight-week study was conducted at
the goat unit of Colegio Superior Agropecuario in the State of Guerrero, México that used 23 Criollo
(local) and 23 Nubian kids distributed into four treatments: (a) 12 inoculated Criollo (IC), (b) 11
control Criollo (CC), (c) 12 inoculated Nubian (IN), and (d) 11 control Nubian (CN). To measure
differences in gip, they were inoculated experimentally with 4,500 infective larvae (L3) of Haemonchus
contortus. The response variables were the number of eggs per gram of faeces (epg) and weekly body
weight gains (WWG). The statistical design was a split-plot in a 2 x 2 factorial arrangement with repeated measures. Statistical analysis was performed by the mixed procedure of SAS, including kid
genotype (G) and inoculation (I) as fixed effects, and kid as a random effect, plus week (W) as a time
factor and live body weight (BW) as a covariate. Before the statistical analysis was performed, epg was
transformed to [Ln (epg + 10)] to approximate a normal distribution. The results indicated that G, I, W,
plus the interactions G x I, I x W, G x W and G x I x W affected (P <; 0.01) [Ln (epg + 10)]. The least
square means for epg were 1,265 ± 51.5, -48 ± 46.5, 2,686 ± 52, and -77 ± 61, for IC, CC, IN and
CN, respectively. For the inoculation effect, the means were 1,975 ± 38 and -62 ± 43 for inoculated and
non-inoculated kids, respectively. Fecal counts increased with time (week). As a covariate, BW had a
significant (P < 0.01) linear effect on both [Ln (epg + 10)] and WWG. On the other hand, I, W plus
the interaction G x W had a significant (P < 0.01) effect on WWG; the means, according to I, were 0.25 ± 0.07 and 0.09 ± 0.08 for inoculated and non-inoculated kids, respectively, whereas, according to
W, the general pattern was to lose weight as the kids approached eight weeks. Criollo goats represent an
alternative for improvement of traditional herds in areas where it is difficult and expensive to apply
antihelmintics.
440
Population Age Structure of Discocotyle sagittata (Monogenea) in Farmed Rainbow Trout, Oncorhynchus Mykiss. M. RUBIO-GODOY*, Instituto de Ecología, A.C, Xalapa, Veracruz, México, and R.C.
TINSLEY, School of Biological Sciences, University of Bristol, Bristol, U.K.
Temperature in the Isle of Man, Great Britain, is generally below 10°C half the year, from November to
April. During three consecutive years, samples were taken at two fish farms in May (following six
months less than 10°C) and in November (after a semester more than 10°C) to study the populations of
Discocotyle sagittata on rainbow trout, Oncorhynchus mykiss. Four distinct types of parasite population
structure were found: two in May and two in November. The first May scenario shows no major transmission takes place during the cold season, because the majority of parasites found were adults, and
almost no developing worms occurred. The second May scenario shows similar burdens of mature and
freshly invaded worms, indicating massive transmission can take place when permissive temperatures
allow the mass hatching of eggs laid in winter/spring. The first November sample illustrates continuous
transmission over several months, as all parasite developmental stages are represented. The second
November sample shows evidence of differences in susceptibility among hosts, because despite recent,
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ABSTRACTS
intense transmission, some hosts carrying relatively low burdens of adult parasites experienced little or no
successful recruitment during appreciable periods of time. These results provide evidence of the effect of
temperature in shaping the population age structure of D. sagittata.
441
Gyrodactylus sp. Infection in Four Genetic Groups of Tilapia Farmed in Veracruz, México. M. RUBIOGODOY*, Instituto de Ecología, A.C, Xalapa, Veracruz, G. MUÑOZ-CÓRDOVA, M. GARDUÑOLUGO, G. MERCADO-VIDAL, Instituto de Ecología, A.C, Xalapa, Veracruz, México, and M. SALAZARULLOA, CEIEGT, Facultad de Medicina Veterinaria y Zootecnia, UNAM, México.
Four genetic groups of farmed tilapia were monitored monthly for infection with Gyrodactylus sp.
(Monogenea) from birth to an age of six months. The tilapia genetic groups studied were: wild type Nile
tilapia (Oreochromis niloticus), red O. niloticus, red Mozambique tilapia (Oreochromis mossambicus), and the
composed red hybrid tilapia Pargo–UNAM, whose genetic composition is 50% Florida red tilapia, 25%
rocky mountain tilapia, and 25% red variant O. niloticus. Fish types were kept separate throughout, but
exposed to water obtained from the river Nautla and the same environmental conditions. The prevalence
of Gyrodactylus infection was 85–100% for all fish, starting with the first sampling, immediately after
sexual reversion. Abundance of Gyrodactylus on Pargo–UNAM was significantly higher (overall highest
abundance ± SE 104.8 ± 36.95 worms/host, range 9–216) than that of other fish types on all samplings, except month 4, when red Nile tilapia had comparable burdens. Mozambique tilapia consistently
had the lowest abundance (overall highest abundance ± SE 26.5 ± 8.22 worms/host, range 6–60).
Despite the different burdens recorded in distinct tilapias, parasite abundance exhibited similar seasonality, with increases and decreases simultaneous in all fish groups. Changes in abundance do not correlate
to temperature changes. Initially, most Gyrodactylus occurred on the caudal and dorsal fins, which held
65–72% of parasites. Microhabitat use changed over time, with most (61–85%) worms occupying the
pectoral and pelvic fins after six months. Increases of parasite abundance seem to correlate to changes in
microhabitat use, suggesting localized host immunity may be controlling worm burdens.
442
In vitro Reproduction and Survival of Microphallus turgidus (Trematoda: Microphallidae). O.J. PUNG*,
M.H. LANCASTER, C.E. JARROUS, Department of Biology, Georgia Southern University, Statesboro
GA, and E.D. BROWN, Department of Biology, University of Southern Mississippi, Hattiesburg MS,
USA.
The successful in vitro cultivation of adult trematodes could obviate the need for vertebrate hosts in the
laboratory and facilitate studies on both the basic biology of the parasites and the development of
anthelminthic drugs. The goal of our project was to measure the in vitro survival of Microphallus turgidus
and its ability to produce eggs under different culture conditions. Grass shrimp (Palaemonetes pugio)
infected with M. turgidus were collected in salt marshes on the Georgia coast. Shrimp were dissected in
0.7% saline to obtain metacercarial cysts. Cysts were washed three times with Hanks’ Balanced Salt
Solution containing penicillin and streptomycin and incubated overnight at 32°C or 37°C to allow
excystation. Excysted worms were cultured in RPMI-1640 supplemented with 20% chicken, horse, or
calf serum and antibiotics at 32°C and 37°C in 24-well tissue culture plates. Parasites survived for at least
two weeks under all conditions with the highest percent survival occurring in serum-supplemented
media. Production and release of embryonated eggs was greatest at 37°C in media containing 20% horse
serum. Egg release peaked during the first few days in culture. Studies concerning the infectivity of eggs
to the hydrobiid snail Spurwinkia salsa are in progress. (Partially funded by the NSF-REU Program
[CHE-0552745].)
443
Zoonotic Parasites of Unusual Occurrence in Canada. T.W. GYORKOS*, Department of Epidemiology,
Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada, J. DEAR, College
of Veterinary Medicine, University of Georgia, Athens GA, USA, E. KOKOSKIN, Tropical Disease
Centre, McGill University Health Centre, Montreal, Quebec, A. VILLENEUVE, Ecole de Médicine
Vétérinaire, Université de Montréal, Montreal Quebec, M. NDAO, B.J. WARD and J.D. MACLEAN,
Tropical Disease Centre, McGill University Health Centre, Montreal, Quebec, Canada.
249
ABSTRACTS
Introduction: Zoonotic parasites can present a diagnostic challenge because they sometimes occur in
unusual places, at unusual times, or in unusual people. Increased community awareness is required to
reduce exposure and increased clinical awareness is required to ensure timely diagnosis and appropriate
treatment. Case histories from Quebec, Canada: The following are examples of recent cases of endemic
and imported zoonotic infection in Quebec. Among the endemic infections are: (1) Trichinella nativa
infection caused by eating raw or undercooked infected walrus or bear meat; (2) Sylvatic Echinococcus
granulosus infection likely originating from wild infected canines; (3) probable Strongyloides procyonis
infection, acquired from contact with raccoon feces-contaminated playground soil; and (4) North
American liver fluke disease. Among infections imported into Quebec are cases of pastoral hydatid
disease, cysticercosis and visceral, mucocutaneous and cutaneous leishmaniasis. Discussion: These case
studies highlight the importance of an expert diagnostic parasitology laboratory, a widely recognized
clinical centre of excellence in parasitology, and a well informed public health system. Preventive measures targeting specific zoonoses, especially endemic infections, have been developed and implemented.
Effectively communicating knowledge of risks, and compliance with preventive measures among travelers to endemic regions, remains a challenge. Conclusion: Increased efforts must be made to increase
awareness of zoonotic parasite risk in new at-risk populations identified following unusual occurrences,
in local communities whose risk is associated with known risk factors, and in different subgroups of the
traveling population where, among preventive measures, should be included advice on post-travel clinical
consultation.
444
Seroprevalence of Toxoplasma gondii Antibodies in Sheep of Puebla, México. H. CABALLEROORTEGA, Lab. Inmunología Experimental, Instituto Nacional de Pediatría, México DF, H. QUIROZROMERO, Depto. Parasitología, FMVZ, UNAM, México DF, S. OLAZARÁN-JENKINS, Centro Experimental Las Margaritas, INIFAP, Puebla, H. GONZÁLEZ HENKEL, Depto. Parasitología, FMVZ, UNAM,
México DF, and D. CORREA*, Lab. Inmunología Experimental, Instituto Nacional de Pediatría, México
DF, México.
An extremely variable prevalence of Toxoplasma gondii infection has been found in sheep from different
parts of the world. The most important source for sheep and goats kept mostly on pasture are oocysts
shed by cats with their feces. In México, only two studies have been carried out in sheep raised in small
flocks during the 1990s; they revealed a prevalence from 20 to 55% in three central states of México, all
of them with a dry, warm climate. It is known that T. gondii prevalence is higher in moist–warm places
than in other environments. For this reason, we sampled sheep from an experimental farm located in the
Puebla State, which has propitious climate for this protozoan to disperse. One hundred and four serum
samples of sheep were analyzed by ELISA and western blot in order to determine anti-T. gondii antibodies. The seroprevalence was 71.1% (CI = 62, 4–79.8%) by ELISA and the results were confirmed by a
commercial kit (87.5% of concordance). At least eight bands ranging from 20 to 180 kDa were detected
in the positive sera by immunoblotting. Fifty-six of these animals were sampled 10 months later and
were tested again. The prevalence did not change significantly, and 80% correlation was observed in
absorbance values. One sheep became positive in the second sampling, indicating an incidence rate of
around 2.1% per year. Higher prevalence rates of toxoplasmosis in moist–warm compared to cold
atmosphere is attributed to the longer viability of T. gondii oocysts. This may explain the high T. gondii
prevalence in Puebla State, which apparently has favorable climatic conditions for the transmission of this
protozoan. In conclusion, our results confirm the presence of anti-T. gondii antibodies in sheep and
suggest that this species may constitute one of the main reservoirs of T. gondii among domestic animals.
Current studies are in progress to isolate and genotype the parasites of positive animals.
445
Biology of the Trout Cecal Nematode, Truttaedacnitis truttae in the Colorado River, Grand Canyon,
Arizona: An Update. R. COLE*, USGS National Wildlife Health Center, Madison WI, A.
CHOUDHURY, St. Norbert College, DePere WI, and D. REINITZ, USGS National Wildlife Health
Center, Madison WI, USA.
Truttaedacnitis truttae, the cecal nematode of trout, utilizes lampreys (Lampetra spp.) as an intermediate
host in Europe. Lampreys are not present in the Colorado River system in the Grand Canyon, yet T.
250
ABSTRACTS
truttae is very common in rainbow trout there. Our previous studies sampled rainbow trout in March
and October, 2002 and April, 2003 and revealed that L3 stages were present in intestinal tissues with
later-stage juveniles and adults in the intestinal tract, primarily the cecal region of the small intestine.
These findings suggest a histotropic phase in the life cycle, which is known from other cucullanids.
Prevalence was 100% and the worm burden also was correlated positively with the size class of fish. All
fish examined were infected and lesions were mild to severe. In October, 2006 additional samples were
examined. In comparison to samples from previous years, 81% of fish were infected, with only a very
weak positive correlations between worm burden and fish size. A T. truttae PCR probe based on the
ITS-1 region of the rRNA genome was designed to test for the presence of larval T. truttae in invertebrate intermediate hosts from the Colorado River. On initial screening, a positive signal was obtained on
extracts from Gammarus lacustris. The pathogenicity of this nematode may be exacerbated by its histotropic phase of development and the synergistic effects of a changing food base in the river that focus
transmission.
446
Analysis of Host Behaviors and Endoparasitic Infections in Migratory Birds from the Purchase Knob,
Great Smoky Mountains National Park, Lake Junaluska, North Carolina, USA. V.R. DIDERRICHFAULKNER, Department of Allied Health, Lincoln Memorial University, Harrogate TN, C.T.
FAULKNER*, Department of Comparative Medicine, Univeristy of Tennessee College of Veterinary
Medicine, Knoxville TN, and P.J. SUPER, Appalachian Highlands Learning Center at Purchase Knob,
Great Smoky Mountains National Park, Lake Junaluska NC, USA.
The high elevation (> 5,000 feet) of the Great Smoky Mountains National Park is a unique environment
for studying ecologic relationships between avian hosts and factors influential for parasite transmission.
Fecal samples (n = 390) representing 40 species of passerine birds were examined for parasitic infection
in conjunction with the All Taxa Biodiversity Inventory (ATBI) and the Monitoring Avian Productivity
and Survivorship (MAPS) projects conducted in the Great Smoky Mountain National Park. The overall
prevalence of infection was 21%. Diagnostic stages of parasitic species included: coccidia oocysts from
Eimeria sp, Isospora sp. or Atoxoplasma sp, nematode eggs from Syngamus sp., Capillaria sp., superfamily
Trichostrongyloidea, and Spiuroidea, and cestode eggs from the family Hymenolepididae. Because the
effects of foraging habitat, diet, and migratory behavior on patterns of parasitic infection in this host
population are poorly understood, birds identified as ground or canopy foragers were analyzed according
to their foraging habitat, dietary preferences as insect-eaters or seed/fruit/berry eaters, and residential
status as neotropical migrants or resident/short distance migrants. Although an unequivocal statistical
association (chi-square, p > 0.05) between foraging habitat, diet, migratory behavior, and parasitic
infection was not supported by these comparisons, insect-eating birds exhibited a tendency to harbor
parasitic infections (p = 0.07). Our results may be confounded, however, by the observation that many
bird species inhabiting the high-elevation zone of the Great Smoky Mountains are dietary generalists
during the juvenile stages in their life cycle and traditionally defined seed-eaters also consume insects
prior to adulthood.
447
Veterinarian’s Role in Preventing Zoonotic Transmission of Intestinal Parasites from Pet Dogs and Cats
to People. P.M. SCHANTZ, Parasitic Diseases Division, National Center for Zoonoses, Vectorborne and
Enteric Diseases, Centers for Disease Control and Prevention, Atlanta GA, USA.
Dogs and cats, present in approximately 60% of all U.S. families/households, are hosts to numerous
intestinal parasites that create risks for zoonotic transmission to humans through direct contact and
environmental contamination with infectious stages. Potentially zoonotic parasites of dogs and cats
include the maternally transmitted intestinal roundworms and hookworms whose infective stages may
contaminate and persist in the peri-domestic environment. Infection of humans by Toxocara canis and T.
cati cause larva migrans syndromes (visceral, ocular and “covert”) in humans who accidentally ingest
infective eggs from contaminated environments. Dipylidium caninum tapeworms are acquired through
accidental ingestion of dog and cat fleas, and Echinococcus spp.of dogs and cats may infect humans with
larval stages that cause cystic or tumorous growths in liver and other visceral organs. Protozoal parasites,
including Cryptosporidium and Giardia spp., may cause diarrhea. Toxoplasma gondii may be transmitted by
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ABSTRACTS
the fecal–oral route from infected cats and lead to serious damage to infected humans. Children are at
greatest risk of exposure to zoonotic parasites of pets because of their play habits and affection for pets.
Pet owners are poorly informed of potential zoonotic threats and therefore are unlikely to take steps to
fully protect themselves. Veterinarians in practice are on the “front lines” of prevention of transmission of
pet-associated zoonotic parasite infections because of their knowledge of these potential risks and
through their contact with pet owners. This presentation will summarize data on the prevalence of
potentially zoonotic intestinal parasites in dogs and cats, the life cycles, modes of transmission and the
diseases that they cause in infected humans. The role of practicing veterinarians in preventing zoonotic
transmission includes diagnosis and timely preventive treatment of pets as well as educating pet owners
about the zoonotic risks and how to avoid them.
448
Taenia solium Taeniasis and Cysticercosis in Southern México, 1996–2005. R. RODRÍGUEZ-CANUL*,
J.A. PÉREZ VEGA, Laboratorio de Inmunologia y Biología Molecular, Recursos del Mar, CINVESTAV
IPN, Unidad Mérida, Mérida, Yucatán, J.L. DOMINGUEZ-ALPIZAR, FMVZ-UADY, Xmatkuil, Mérida,
México, F. CEN-AGUILAR, Departamento de Investigación, CBTA Xmatkuil, Mérida, México, J.C.
ALLAN, Pfizer Animal Health. Pfizer Ltd., Sandwich, Kent, U.K., and P.S. CRAIG, Cestode Zoonoses
Research Group, University of Salford, Salford, U.K.
From 1996 to 2005, a comprehensive study of Taenia solium taeniasis/cysticercosis was performed in six
rural communities in southern México. A census and a questionnaire designed to collect socio-economic
data, sanitary facilities and general knowledge about the life cycle of T. solium was performed in each
community. After informed consent, a blood and a fecal sample was collected from all willing individuals.
Also, from pigs, a blood sample was taken. Risk factors were estimated by X2 using Odd ratio in EpiInfo 6.0. Seroprevalence of human and porcine cysticercosis were assessed with an immunoblot-26 kDa.
Prevalence of taeniasis was detected by microscopy and by coproantigen-ELISA. In Tedzidz (20º58′N,
90º12′W), seroprevalence of human cysticercosis (HC) was 3.7%, and porcine cysticercosis (PC) was
35%. Prevalence of taeniasis (T) was 1.5%. In Texán de Palomeque (20º60′N, 90º19′W), HC was 3.8%,
PC was 5.6% and T was 0.8%. In Tixcacaltuyub (89º94′N, 20º52′W), HC was 4%, PC was 26.5%, and
T was 0.7%. In Kochol (20º37′N, 90º10′W), HC was 3%, PC was 12%, and T was 1.7%. In Santo
Domingo (20º39′N, 90º11′W), HC was 2%, PC was 2.7%, and T was 2.0%. In San Rafael (20º36′N,
90º09′W), HC was 2.3%, PC was 0.5%, and T was 0.6%. Traditional pig husbandry practices, a lack of
adequate sanitary services and a lack of knowledge about T. solium life cycle are main factors associated to
transmission of T. solium.
449
Science Communication as a Means of Preventing Infectious Diseases: Development of a Health
Communication Programme for the Critical Learning of Health Information. L. VARGAS-PARADA*, S.
GARCÍA, U. RODRÍGUEZ and M. LOZANO, Unidad de Periodismo Científico, Dirección General de
Divulgación de la Ciencia, UNAM, México DF, México.
Taenia solium is endemic in México. As with many other parasitic diseases, it is closely related to poverty
and a low educational level of the population, which results in deficient hygienic practices. Previous
studies have shown that health education interventions increase the level of knowledge of the population.
Modification of risk practices are less apparent, however, suggesting that changes in knowledge do not
necessarily modify behaviour. We selected a rural community where risk factors associated to the prevalence of T. solium were present, established contact with local authorities, made a census of human and
pig population, determined the prevalence of porcine cysticercosis by tongue examination, and assessed
hygienic practices and sanitary conditions by direct observation. An ethnographic study was initiated
with in-depth interviews and non-participative observation. With the gathered information, the contents
and formats of a health communication programme were designed, and a basic model was developed to
represent the relevant points of the process of communication. The aim of the programme is to promote
critical thinking and inquiry in the participants, encouraging team work for defining and developing
action and intervention plans to solve health problems in their community. Although the program is
directed at people between 12–25 years of age, participation of the entire community is required. The
scientific method lies at the centre of analysis, inference, evaluation, deductive and inductive reasoning,
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ABSTRACTS
which is why we chose this method as a way of promoting critical skills in the participants. Each skill is
related to one of the steps in the method, and each step is revised through a series of workshops. A field
research project allows the participants to put into action their recently learned skills. We expect that
through active involvement of the participants in the process of discovering and understanding healthrelated information, they may find a context that makes sense of prevention, encouraging them to
modify their risky behaviours as a result of acquiring scientific knowledge. (Grant from Fondo Sectorial
en Salud CONACYT 2004-C01-086.)
450
Malaria Relapse or Re-infection and Impact in the Transmission and Persistance of the Disease in
Affected Regions of México: Some Advances to Molecular Identification. L. GONZÁLEZ-CERÓN*,
M.A. SANDOVAL, J.A. NETTEL-CRUZ, Parasitology Department, Regional Center for Public Health
Research-INSP, Tapachula, Chiapas, M.H. RODRÍGUEZ, National Institute for Public Health, Cuernavaca, Morelos, V. CHOY, Parasitology Department, Regional Center for Public Health Research-INSP,
Tapachula, Chiapas, and R. GÓMEZ, Entomology department, Center for Research of Infectious
Diseases, INSP, Cuernavaca, Morelos, México.
Malaria is a disease of importance in public health. In México, after extensive measures of control, the
number of malaria cases diminished considerably; nevertheless, in some regions of the country, the
transmission persists. It will be necessary to identify the factors that favor this persistence to contribute
to the control of the disease. In Plasmodium vivax, relapse infections are involved in initiating malaria
transmission each period; however, no detailed studies of the dynamics have been done, and molecular
tests are needed to identify the real relapse occurrence. In this study, patients from Southern Chiapas
presenting recurrent infections of the last 12 years were temporally and spatially analyzed to investigate
its role to activate or maintain its transmission in the beginning, duration and end of each season. In
order to distinguish if recurrent infections belong to a relapse, some paired blood samples were obtained
from P. vivax-infected patients and the msp1 gene polymorphism and CSP repeat-genotype were analyzed. A group of affected patients displayed recurrent cases at the beginning and during the active
transmission every year, widely distributed in the affected region. Preliminary data showed that some
recurrent cases were identified as relapses and others as possible re-infections. The identification of
relapses is associated with failure of treatment or treatment distribution. Also, the identification of
parasite genotypes and the population dynamics of re-infections and relapses will allow us to understand,
in parasite terms, causes of malaria persistence to developed, appropriate tools to contribute to overcome
or reduce the disease.
451
Ultrastructure of Ornithodiplostomum ptychocheilus Diplostomula During Invasion of the Brain of the
Fish Intermediate Host. D. CONN*, School of Mathematical and Natural Sciences, Berry College,
Mount Berry GA, USA, C.P. GOATER and D. BRAY, Department of Biological Sciences, Univesity of
Lethbridge, Lethbridge, Alberta, Canada.
We examined tegumental development of the diplostomulum of Ornithodiplostomum ptychocheilus with
respect to structural transformations that have functional relevance to the invasion, migration and siteestablishment processes in the brain of the fish second-intermediate host, Pimephales promelas. Our
studies were based on fish and parasites naturally occurring in Alberta, Canada. Using a combination of
brightfield, scanning electron (SEM), transmission electron (TEM), and confocal (CM) microscopy, we
demonstrated that the diplostomula become established in the outer region of the optic lobes within 24–
48 hours of host skin penetration, and continue to grow and transform over a period of 4–14 days.
During this period, the J-shaped body consists of two distinct regions: (1) a highly motile spinous
prosoma with distinctive tegumental spines that are shaped in such a way that would facilitate burrowing
through host tissues; and (2) an opithosoma, the tegument of which is elaborated into a dense uniform
layer of long thin microvilli. The prosoma is alternately invaginated into and everted from the opisthosoma, thus constituting a protrusible proboscis. By day 14 postinfection, the body has lost this bipartite
structure and has taken on the uniformly flattened form characteristic of metacercariae and adult trematodes. The transitory complex structure of the diplostomula appears to be well suited to burrowing
through host tissues (primarily by action of the prosoma), followed by rapid disaggregation of host
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ABSTRACTS
tissue and nutrient accumulation (primarily by action of the opisthosoma) in preparation for metacercarial encystment. These results clarify the developmental and functional ultrastructure during host
invasion and establishment of a common strigeoid. This differs from previous descriptions by other
authors of schistosomula of Schistosoma spp. that similarly migrate through their host following skin
penetration.
452
The Impact of the Arrival of Hystricognath and Sigmodontinae Rodents on the Phylogeny of Neotropical Nematodes. F.A. JIMÉNEZ*, The Harold W. Manter Laboratory of Parasitology, University of Nebraska State Museum, Lincoln NE, and S.L. GARDNER, The Harold Manter Laboratory of Parasitology,
University of Nebraska State Museum, Lincoln NE, USA.
Among the South American endemics, Xenarthra and Didelphiomorphia have fossil representation
throughout the Cenozoic. In contrast, both Hystricognath and Sigmodontinae rodents arrived later in
the continent during the Eocene and Plio-Pleistocene, respectively. These mammals are infected by a
variety of heterakoid and trichosrongyloid nematodes that are believed to have originated in the South
American endemics. Their phylogenetic structure reveals clades involved in events of host-switching,
probably caused by the convergence in both habitat use and feeding habits of their hosts. According to
the fossil record and estimates using molecular clock, the origin of xenarthrans