Trypanosomes

Definition

Kinetoplastid flagellate protists (family Trypanosomatidae) characterized by a single flagellum and undulating membrane, typically exhibiting corkscrew-like motility. Obligate parasites with life cycles alternating between invertebrate vectors (primarily insects) and vertebrate hosts; several species cause significant human and veterinary diseases including African trypanosomiasis (sleeping sickness) and Chagas disease. Insect vectors include tsetse flies (Glossina spp.) for Trypanosoma brucei complex and triatomine bugs (kissing bugs, subfamily Triatominae) for T. cruzi.

Etymology

Greek trypanon (borer, auger) + soma (body), referring to the corkscrew drilling motion observed in motile forms

Example

Trypanosoma brucei gambiense, transmitted by tsetse flies in sub-Saharan Africa, evades host immunity through antigenic variation of its variant surface glycoprotein coat—a mechanism studied extensively in both parasitology and vector biology.

Synonyms

• trypanosomatids (broader, includes related genera)

Related Terms

• tsetse fly
• triatomine bug
• kinetoplast
• vector-borne disease
• African trypanosomiasis
• Chagas disease
• antigenic variation
• sleeping sickness

Usage Notes

In strict usage, 'trypanosomes' refers specifically to members of the genus Trypanosoma, while 'trypanosomatids' encompasses the broader family Trypanosomatidae including Leishmania and other genera. The term is sometimes used loosely for any trypanosomatid in clinical contexts. Distinguish from trypomastigote (a specific morphological stage, not the organism itself).