Trypanosoma species
Trypanosoma brucei, trypomastigotes, thin blood film
Shown are the trypomastigotes of Trypanosoma brucei on a Giemsa-stained thin blood film. Unlike Trypanosoma cruzi, there is no amastigote stage. Note that the trypomastigotes are extracellular. They have a nucleus, small kinetoplast at the posterior end, and a single flagellum that emerges from the anterior end.
Trypanosoma cruzi, trypomastigotes, thin blood film
Shown are the trypomastigotes of Trypanosoma cruzi in a Giemsa-stained thin blood film. Note that the trypomastigotes are extracellular. They have a nucleus, large kinetoplast, and a single flagellum that emerges from the anterior end. They are best differentiated from the similar-appearing trypomastigotes of Trypanosoma brucei by their larger kinetoplast; they also commonly assume a "C" shape but this is less specific. Trypanosoma cruzi also has an intracellular non-motile stage called an amastigote (not shown).
Trypanosoma cruzi, amastigotes, tissue
Trypanosoma cruzi, the agent of Chagas disease, has both motile trypomastigote and non-motile amastigote forms. While the trypomastigotes are present in the blood, amastigotes are found in tissues. These photos show clusters (pseudocysts) of amastigotes in heart muscle (stained with hematoxylin and eosin; 200 to 400x total magnification).
