Trypanosomes are haemoflagellates that live in the blood and tissues of their human hosts.

1. African
Trypanosomiasis
Huda Alislam Talab
B.Sc., M.Sc. Medical Parasitology
University of Medical Sciences and
Technology (UMST)

2. T.Brucei T.Cruzi
Infective stage Metacyclic trypomastigote Metacyclic trypomastigote
Diagnostic stage Trypomastigote Trypomastigote / Amastigote
Vector Tsetse fly Triatomine bug (kissing bug)
Disease African trypanosomiasis or American trypanosomiasis or
(sleeping sickness) (Chagas disease )
Site of bite chancre Chagoma

3. Triatomine bug(kissing bug)

4. Triatomine bug(kissing bug)

7. Tsetse fly

8. Morphology of Trypomastigote

9. Trypomastigote of T.cruzi

11. Trypomastigote of T.brucei

15. Laboratory diagnosis of T.brucei
Microscopic examination of :
Chancre fluid
Lymph node aspirates
Blood
Bone marrow
Cerebrospinal fluid

16. 1) Examination of chancre fluid for trypanosomes
When a chancre is present (more
commonly seen in early T. b. rhodesiense
infections than in T. b. gambiense
infections)

18. 2) Examining blood for trypanosomes
 Examination of stained blood film.
 Microhaematocrit concentration technique.

19. Human African
Trypanosomiasis

23. An impression smear of the trypanosomes and the RBC in
the capillaries.

25. 3) Examination of lymph glands aspiration
Examining aspirates from enlarged lymph glands
for trypanosomes, particularly when T.b.gambiense
trypanosomiasis is suspected.
Enlarged lymph glands called wintterbotoms sign.

26. winterbottoms sign

28. Collecting lymph fluid to
examine for T.b.gambiense
T.b.gambiense in stained
smear of lymph fluid

29. Collecting lymph fluid to examine for
T.b.gambiense

31. 4) Examining cerebrospinal fluid (C.S.F)
When there is involvement of the CNS in African trypanosomiasis
the following may be found in C.SF :
Few trypanosomes
More than 5 white cells/µl
Morula (Mott) cells (IgM producing plasma cells)
 IgM, usually more than 10% of the total C.S.F. protein
Raised total protein

37. Change in behavior : Neurological complications can occur as a
result of infection

43. 5) Serological testing
The card agglutination test for trypanosomiasis (CATT)
Indirect haemagglutination (IHA)
Indirect immunofluroscence (IIF)
Enzyme linked immunosorbent assay (ELISA)
Complement fixation test (CFT)

44. 6) Culture
The organisms are difficult to grow, hence
culture is not routinely used for primary
isolation of the parasite.

45. Other tests
Measurement of haemoglobin→ Rapidly developing
anemia with reticulocytosis
 Measurement of the erythrocyte sedimentation rate (ESR)
→ A significant and rapid rise in ESR due to changes in
plasma proteins.

46.  Total white blood cell count and differential →A moderate
leucocytosis with monocytosis, lymphocytosis and presence
of plasma cells .
 Checking urine for protein, cells, and casts once treatment
has started.