GENERAL PARASITOLOGY TEST 1
1.
In a patient with diarrhea, occasionally Entamoeba histolytica/E. dispar (Entamoeba
histolytica complex) (four-nucleated cysts, no chromatoidal bars) are identified as being
present; however, these cells, which are identified as protozoa, are really:
A. Macrophages
B. Epithelial cells
C. Eosinophils
D. Polymorphonuclear leukocytes
2.
Parasitic organisms that may be transmitted sexually do not include:
A.
B.
C.
D.
3.
The use of Neti pot nasal irrigation has been linked to infections caused by:
A.
B.
C.
D.
4.
Entamoeba histolytica, Entamoeba hartmanni
Giardia lamblia (G. intestinalis, G. duodenalis), Cryptosporidium spp.
Dientamoeba fragilis, Trichomonas vaginalis
Pentatrichomonas hominis, Cystoisospora belli
Which specimen is least likely to provide recovery of Trichomonas vaginalis?
A.
B.
C.
D.
6.
Naegleria fowleri
Entamoeba histolytica
Trichomonas vaginalis
Microsporidia
The following organisms have been implicated in waterborne and foodborne outbreaks within
the United States. The suspect organisms are:
A.
B.
C.
D.
5.
Entamoeba histolytica
Dientamoeba fragilis
Diphyllobothrium latum
Trichomonas vaginalis
Urine
Feces
Urethral discharge
Vaginal discharge
An Entamoeba histolytica (true pathogen) trophozoite has which of the following
characteristics?
A.
B.
C.
D.
Compact karyosome in the nucleus, ingested red blood cells (RBCs), and clear pseudopodia
Ingested RBCs, clear pseudopodia, and uneven chromatin on the nuclear membrane
Ingested polymorphonuclear leukocytes (PMNs), and large glycogen vacuoles
Large blot-like karyosome, and ingested PMNs
pg. 1 Parasitology General Test 1
7.
A six-year-old boy with meningitis is seen in the emergency room; he has a history of
swimming in a warm-water spring. Motile amebae that measure 10 microns are seen in the
CSF and are most likely:
A.
B.
C.
D.
8.
Suspect amebae from a gum lesion were seen on a Gram stain. Additional routine trichrome
staining (used for fecal smears) demonstrated amebae with a single nucleus and ingested
PMNs. The correct identification is:
A.
B.
C.
D.
9.
Eosinophils
Lymphocytes
Monocytes
Neutrophils
Recommended methods for the recovery and identification of Cystoisospora belli are:
A.
B.
C.
D.
12.
Entamoeba histolytica
Blastocystis spp.
Giardia lamblia (G. intestinalis, G. duodenalis)
Entamoeba coli
Charcot-Leyden crystals are occasionally seen in stool specimens, may be associated with an
immune response, and are formed from the breakdown products of:
A.
B.
C.
D.
11.
Trichomonas tenax
Entamoeba coli
Entamoeba gingivalis
Entamoeba polecki
Worldwide the most common parasitic organism identified from stool is:
A.
B.
C.
D.
10.
Iodamoeba bütschlii trophozoites
Endolimax nana trophozoites
Dientamoeba fragilis trophozoites
Naegleria fowleri trophozoites
Gram stain and direct wet mount
Trichrome stain and concentration sediment
Silver stain and direct wet mount
Modified acid-fast stain and concentration sediment
Which of the following organisms does not have a cyst form in the life cycle?
A.
B.
C.
D.
Balantidium coli
Trichomonas vaginalis
Dientamoeba fragilis
Chilomastix mesnili
pg. 2 Parasitology General Test 1
13.
In a fecal concentration sediment examination, an operculated tapeworm egg that might be
seen is:
A.
B.
C.
D.
14.
The ingestion of poorly cooked infected pork can result in an infection with:
A.
B.
C.
D.
15.
Saline; to prevent premature hatching of the eggs
Formalin; to preserve eggs if present
Water; to encourage eggs to float
None of the above
The following groups of helminth eggs are listed in size from largest to smallest; which group
is correct?
A.
B.
C.
D.
19.
Toxoplasma gondii and serology
Cryptosporidium spp. and immunosuppressed patients only
Echinococcus granulosus and hydatid cysts
Strongyloides stercoralis and internal autoinfection
When performing a concentration for the recovery of schistosome eggs from fresh urine or
stool, what solution should be used and why?
A.
B.
C.
D.
18.
Angiostrongylus and CSF examination
Dracunculus and skin biopsy
Onchocerca and blood smear
Toxocara and serology
Which of the following organism/information combinations is incorrect?
A.
B.
C.
D.
17.
Taenia solium and Trichinella spiralis
Taenia saginata and Hymenolepis nana
Trichuris trichiura and Hymenolepis diminuta
Diphyllobothrium latum and Ascaris lumbricoides
Visceral larva migrans has been associated with which of the following organisms and
diagnostic procedures:
A.
B.
C.
D.
16.
Dipylidium caninum
Clonorchis sinensis
Diphyllobothrium latum
Paragonimus westermani
Fasciola hepatica, Clonorchis sinensis, Taenia spp.
Hymenolepis nana, Paragonimus westermani, Fasciolopsis buski
Schistosoma mansoni, Hymenolepis diminuta, Opisthorchis spp.
Ascaris lumbricoides, Schistosoma haematobium, Diphyllobothrium latum
Examination of a sputum specimen may reveal infection with:
pg. 3 Parasitology General Test 1
A.
B.
C.
D.
20.
Strongyloides stercoralis rhabditiform (non-infective) larvae are characterized by which of the
following?
A.
B.
C.
D.
21.
Complete in terms of recognized pathogens
Incomplete in terms of recognized pathogens
100% sensitive and specific for panel organisms
Less sensitive than available immunoassays
The most appropriate test for the confirmation of infection with Enterobius vermicularis is:
A.
B.
C.
D.
25.
Dog
Cow
Sheep
Human
Molecular panels currently available for the identification of intestinal protozoa are:
A.
B.
C.
D.
24.
Definitive host
Intermediate host
Definitive or intermediate host
None of the above
The adult tapeworm of Echinococcus granulosus can be found in the intestine of the:
A.
B.
C.
D.
23.
Short buccal capsule and large genital primordium
Long buccal capsule and pointed tail
Small genital primordium and pointed tail
Large genital primordium and notch in tail
In infections with Taenia solium, the human can serve as the:
A.
B.
C.
D.
22.
Trichinella spiralis, Paragonimus spp.
Paragonimus spp., Strongyloides stercoralis
Strongyloides stercoralis, Taenia solium
Taenia solium, Cryptosporidium spp.
The routine O&P concentration
The routine O&P permanent stained smear
The cellulose tape or swab method
None of the above
The pathogenicity of Blastocystis spp. has been clarified; newer information suggests that:
A.
B.
C.
D.
The immune capability of the host is totally responsible for symptomatic infections.
Most organisms are misidentified as artifacts.
Nine subtypes/strains included in the name, some are pathogenic and some nonpathogenic.
The number of organisms present determines pathogenicity.
pg. 4 Parasitology General Test 1
26.
Holding blood too long in EDTA prior to thick and thin blood smear preparation can result in
which of the following problems?
A. Changes in parasite morphology, poor staining, and diminished organism numbers within a
few hours.
B. Loss of Schüffner’s dots, poor adherence of blood to the slide, and the initiation of the vector
life cycle within the tube of blood.
C. None of the above.
D. All of the above.
27.
A preliminary test for the presumptive diagnosis of Cyclospora cayetanensis is the use of:
A.
B.
C.
D.
28.
Infections with microsporidial spores can be confirmed using:
A.
B.
C.
D.
29.
Cystoisospora belli and Strongyloides stercoralis
Strongyloides stercoralis and Cryptosporidium spp.
Cryptosporidium spp. and Giardia lamblia (G. intestinalis, G. duodenalis)
Giardia lamblia (G. intestinalis, G. duodenalis) and Cystoisospora belli
Microsporidial infections cause diarrhea, dissemination from the GI tract to other body sites,
and eye infections. Possible routes of infections have been identified as:
A.
B.
C.
D.
32.
The visualization of the parasite within the RBCs.
The ability to identify the parasites to the species level.
The necessity to lake the RBCs during or prior to staining.
The examination of less blood per field than the routine thin blood film.
“Internal autoinfection” can be seen with which of the following parasites?
A.
B.
C.
D.
31.
Phase contrast microscopy and routine trichrome stains.
Electron microscopy and modified acid-fast stains.
Fluorescence microscopy and hematoxylin stains.
Light microscopy and modified trichrome stains.
Routine thick blood films are characterized by which of the following?
A.
B.
C.
D.
30.
Autofluorescence
The examination of a direct wet mount
An immunoassay
A routine trichrome permanent stain.
Ingestion and inhalation
Direct contamination from the environment
All of the above
None of the above
Confirmation of a microsporidial infection can be confirmed by seeing:
pg. 5 Parasitology General Test 1
A.
B.
C.
D.
33.
The oocyst wall.
Sporozoites within the spore.
Evidence of a polar tubule.
Organisms stained with modified acid-fast stains.
A helminth egg with terminal polar plugs is:
A. Ascaris lumbricoides
B. Trichuris trichiura
C. Hookworm
D. Enterobius vermicularis
34.
An immunocompromised patient continues to have diarrhea after a series of 3 O&P
examinations were negative (concentration, permanent stained smears). The most likely
organisms that might be responsible for the patient’s continued symptoms are:
A.
B.
C.
D.
35.
The early ring stages of Plasmodium knowlesi most closely resemble those of:
A.
B.
C.
D.
36.
Ingestion of raw infected freshwater crabs
Skin penetration of cercariae
Peeling the coat from uncooked water chestnuts with the teeth; subsequent swallowing
Ingestion of raw infected freshwater fish
Humans can serve as both the intermediate and definitive host in infections caused by:
A.
B.
C.
D.
38.
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium falciparum
Humans acquire infections with Diphyllobothrium latum adult worms through:
A.
B.
C.
D.
37.
Cryptosporidium spp. and Cystoisospora belli
Microsporidia or Cyclospora cayetanensis
Cryptosporidium spp. and microsporidia
Cystoisospora belli and Cyclospora cayetanensis
Hymenolepis nana
Ascaris lumbricoides
Schistosoma japonicum
Enterobius vermicularis
Babesia spp. are organisms that have been implicated in disease in immunocompetent and
immunosuppressed patients. Morphologically, these parasites resemble:
A. Microsporidian spores
B. Leishmania donovani amastigotes
C. Trypanosome cruzi trypomastigotes
pg. 6 Parasitology General Test 1
D. Plasmodium falciparum ring forms
39.
Toxoplasma gondii is characterized by:
A.
B.
C.
D.
40.
Massive hemolysis and central nervous system involvement are more common with:
A.
B.
C.
D.
41.
Protozoan trophozoites
Motility of helminth larvae
Formation of amoebic pseudopods
Protozoan cysts and helminth eggs
Cysts of Iodamoeba bütschlii typically have:
A.
B.
C.
D.
45.
Enterobiasis – dysentery
Paragonimiasis – hemoptysis
Cryptosporidiosis – watery diarrhea
Toxoplasmosis in compromised host – central nervous system symptoms
The formalin-ether (ethyl acetate) concentration procedure for fecal specimens is primarily
used to demonstrate:
A.
B.
C.
D.
44.
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium falciparum
The incorrect match between disease and symptoms is:
A.
B.
C.
D.
43.
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium falciparum
Older developing stages (trophs, schizonts) of Plasmodium knowlesi most closely resemble
those of:
A.
B.
C.
D.
42.
Possible congenital infections, ingestion of infective oocysts, and ingestion of raw meats
Worldwide distribution and possible difficulties with the interpretation of serological results
Both A and B
None of the above
A large glycogen vacuole
A heavily vacuolated cytoplasm
Chromatoidal bars with rounded ends
Many ingested bacteria and yeast cells
There are relatively few STAT parasitology test requests. The most obvious order would be:
pg. 7 Parasitology General Test 1
A.
B.
C.
D.
46.
The microsporidia are organisms (reclassified from protozoa to fungi) that have been
implicated in human disease primarily in:
A.
B.
C.
D.
47.
The organisms were actually not present in the concentrate sediment
There were too few cysts to allow identification on the stained smear
E. coli cysts were present but poorly fixed due to their impenetrable cyst wall
The concentrate and permanent stained smear were not from the same patient
An immunosuppressed man has several episodes of pneumonia, intestinal pain, sepsis with
gram-negative rods, and a history of military service in Southeast Asia 20 years earlier. The
most likely cause is infection with:
A.
B.
C.
D.
50.
Chilomastix mesnili (lemon/pear shape) and Shepherd’s crook
Hymenolepis nana and striated shell
Wuchereria bancrofti and sheathed microfilariae
Plasmodium malariae and “band trophozoite”
Protozoan cysts were seen in a concentration sediment and tentatively identified as
Entamoeba coli. However, the organisms were barely visible on the permanent stained smear
because:
A.
B.
C.
D.
49.
Adult patients with congenital immunodeficiencies
Patients who have been traveling in the tropics
Pediatric patients under the age of 5
Immunocompromised patients
The incorrect match between organism and characteristic is:
A.
B.
C.
D.
48.
Blood films for malaria
Culture of amoebic keratitis
Ova and parasite examination for giardiasis
Baermann’s concentration for strongyloidiasis
Trypanosoma cruzi
Strongyloides stercoralis
Naegleria fowleri
Paragonimus westermani
When staining Cystoisospora belli oocysts with modified acid-fast stains, the important
difference between these methods and the acid-fast stains used for acid-fast bacilli (AFB) is:
A.
B.
C.
D.
The staining time is much longer with regular AFB acid-fast stains.
The decolorizer is weaker than acid alcohol used for AFB decolorizing.
A counterstain must be used for the modified methods.
The stain is more concentrated when staining for AFB.
pg. 8 Parasitology General Test 1
51.
A 60-year-old Brazilian patient with cardiac irregularities and congestive heart failure
suddenly dies. Examination of the myocardium revealed numerous amastigotes, an indication
that the cause of death was most likely:
A.
B.
C.
D.
52.
Plasmodium vivax and Plasmodium ovale are similar because they:
A.
B.
C.
D.
53.
The lung
The nervous system
The gastrointestinal tract
Mucocutaneous lesions
Organisms and infections that under normal conditions cannot be transmitted in the
laboratory are:
A.
B.
C.
D.
57.
Use of soft contact lenses
Use of hard contact lenses
Use of contaminated lens care solutions
Failure to remove lenses while swimming
The most common microsporidian infections originate in:
A.
B.
C.
D.
56.
Dysentery and amebiasis
Malabsorption syndrome and giardiasis
Cardiac involvement and chronic Chagas’ disease
Myalgias and trichuriasis
Eye infections with Acanthamoeba spp. have most commonly been associated with:
A.
B.
C.
D.
55.
Exhibit Schüffner’s dots and have a true relapse in the life cycle
Have no malarial pigment and multiple rings
Commonly have appliqué forms in the red cells
Have true stippling, do not have a relapse stage, and infect old red cells
The incorrect match between symptoms and disease is:
A.
B.
C.
D.
54.
Leishmaniasis with Leishmania donovani
Leishmaniasis with Leishmania braziliense
Trypanosomiasis with Trypanosoma gambiense
Trypanosomiasis with Trypanosoma cruzi
Taenia solium – cysticercosis
Ascaris lumbricoides – ascariasis
Cryptosporidium spp. – cryptosporidiosis
Enterobius vermicularis – pinworm infection
Key characteristics of infection with the fifth human malaria, Plasmodium knowlesi include:
A. Rapid erythrocytic cycle (24 h), will infect all RBCs, and can cause serious disease
pg. 9 Parasitology General Test 1
B. Erythrocytic cycle limited to young RBCs and causes a relatively benign disease
C. The possibility of a true relapse from the liver, infection in older RBCs, and causes serious
disease
D. Extended life cycle (72 h), will infect all RBCs, and disease is similar to that caused by
Plasmodium ovale
58.
Two helminth eggs that may resemble one another are:
A.
B.
C.
D.
59.
The following organisms are linked with specific, relevant information. The incorrect
combination is:
A.
B.
C.
D.
60.
Diphyllobothrium latum and Paragonimus westermani
Opisthorchis sinensis and Fasciolopsis buski
Taenia saginata and Hymenolepis nana
Ascaris lumbricoides and Trichostrongylus
Strongyloides stercoralis – hyperinfection syndrome
Echinococcus granulosus – hydatid sand
Toxoplasma gondii – serology
Balantidium coli – common in the United States
Parasites that should be considered in a nursery school outbreak of diarrhea include:
A.
B.
C.
D.
Endolimax nana, Giardia lamblia (G. intestinalis, G. duodenalis), and Entamoeba coli
Giardia lamblia (G. intestinalis, G. duodenalis), and Cryptosporidium spp.
Cryptosporidium spp., and Trichomonas vaginalis
Pentatrichomonas hominis, Dientamoeba fragilis, and Endolimax nana
CORRECT ANSWERS:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
D
C
A
B
B
A
D
C
B
A
D
B
C
A
D
B
A
C
pg. 10 Parasitology General Test 1
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
B
A
C
A
B
C
C
D
A
D
C
B
C
C
B
C
D
D
A
D
C
D
C
A
D
A
A
D
B
C
B
B
D
A
D
C
C
B
A
A
D
B
pg. 11 Parasitology General Test 1