Diagnostic Findings [Last Modified: ]
Trypanosomiasis, African
[Trypanosoma brucei gambiense] [Trypanosoma brucei rhodesiense]
Causal Agent Life Cycle Geographic Distribution Clinical Features Laboratory Diagnosis Treatment

Microscopy

The two Trypanosoma brucei subspecies that cause African trypanosomiasis, T. b. gambiense and T. b. rhodesiense, are indistinguishable morphologically.  A typical trypomastigote has a small kinetoplast located at the posterior end, a centrally located nucleus, an undulating membrane, and a flagellum running along the undulating membrane, leaving the body at the anterior end.  Trypomastigotes are the only stage found in patients.  Trypanosomes range in length from 14 to 33 µm.

Trypansoma brucei sp in a thick blood smear Trypanosoma brucei sp. in a thin blood smear
A B

A:  Trypansoma brucei ssp. in thick blood smears stained with Giemsa.
B: Trypanosoma brucei ssp. in thin blood smears stained with Giemsa.

Trypanosoma brucei in a thin blood smear Trypanosoma brucei in a thin blood smear
C D

C, D:  Trypomastigotes of T. brucei ssp. in a blood smear stained with Giemsa.

Trypansoma brucei sp in a thin blood smear Trypansoma brucei sp in a thin blood smear, dividing
E F

E: Trypanosoma brucei ssp. in thin blood smears stained with Wright-Giemsa.
F: Trypanosoma brucei ssp. in a thin blood smear stained with Giemsa.  The trypomastigote is beginning to divide; dividing forms are seen in African trypanosomes, but not in American trypanosomes.

 
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