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Trypanosoma
Causes
Trypanosomiasis
West African
Trypanosomiasis
East African
Trypanosomiasis
T.brucei
T.brucei
gambiense
rhodesiense
Sleeping sickness
Transmitted by
Glossina (tsetse fly)
American
Trypanosomiasis
T.cruzi
Chagas’ disease
Transmitted by
Triatoma (reduviid bug)

The name is derived from the Greek trypaô (boring) and
soma (body) because of their corkscrew-like motion.

Trypanosoma brucei is parasitic protist species
that causes several disease for human and
animals.

Approximately 16-18 million people are currently
infected, 50,000 of which die each year.
Epidemiology
Morphology
 Trypanosomes
are minute actively
motile fusiform protozoa .large oval
nucleus located centeraly near the
posterior end there is a kinetoplast .
A flagellum arise from the kinetoplast
pass along the margin of the
undulating membrane projecting
from the anterior end as a free
flagellum
Trypanosoma parasite
Trypanosoma life stages are:




- Epimastigote - Basal body(Kinetoplast) anterior
of nucleus, with a long flagellum attached along
the cell body.
- Trypomastigote - Basal body posterior of
nucleus, with a long flagellum attached along the
cell body.
Infective stage for vertebrate is metacyclic
trypomastigote.
Infective stage for the invertebrate is
trypomastigote
Life Cycle of Trypanosoma brucei
Reservoirs
For T.b. gambiense, the main
reservoir of infection is humans,
although both wild and domestic
animals have also been seen to harbor
the infection. For T.b. rhodesiense, the
main reservoir for infection is cattle.
However, other domestic animals
(dogs, pigs, and sheep) and many
game animals also carry the infection.
Reservoirs
T.b. gambiense
T.b. rhodesiense
Tsetse flies belong to the genus
Glossina
Mechanism of disease transmission by Glossina
Trypomastigotes
(polymorphic
trypanosomes)
Bite of Glossina
Salivar
y gland
Full of short
stumpy metacyclic
Trypomastigote
Infective
stage
Biological
transmission
3
weeks
Diagnostic
stage
1242µ
Epimastigot
e
Pathogenesis and Clinical Picture
Incubation period (2 weeks)
Trypanosoma chancre (at the site of bite)
Via lymphatics: enlarged lymph nodes especially posterior cervical
region.
(Winterbottom’s sign)
Via blood stream: headache, fever(fluctuating), muscle & joint
pain, irregular erythematous rash.
Invasion of bone marrow
(hypoplastic anaemia)
Enlarged liver & spleen, generalized weakness.
Invasion of CNS: severe headache, mental apathy, slow speech,
deep sleep, coma & death
In East African Trypanosomiasis:
Disease runs more rapid & fatal course
Pathogenesis and Clinical Picture
Trypanosoma chancre
Winterbottom sign
Emaciation
‫على عظم‬
Coma before death
‫جلد‬
Diagnosis
1- Clinical picture
2- Demonstration of trypanosomes:
- Microscopic examination of
unstained or stained blood films
Polymorphic
Trypanosomes
- Culture on suitable medium (N.N.N OR
Weinmann’s media to detect Epimastigote)
- Animal inoculation
* in case of T.brucei rhodesiense injected in lab
Animal produce a new form “Posterior Nucleus
Shift”
Diagnosis
C.S.F
Diagnosis
3- Serological test:
Increased total IgM level in serum due to antigenic
variation of the surface coat of the parasite.
Trypanosome posses genes that code for about 1000
variant forms of their surface glycoproteins (SVG).
Switch to a different variant produces a new generation
not susceptible to attack by immune factors specific to
the previous generation.
Treatment
In early stage of the disease:
Pentamidine OR Suramin
For CNS involvement :
Melarsoprol (i.v)
Control
•
Treatment of patients
•
Control of vectors (Glossina)
•
Pentamidine as prophylactic drug
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