Trichomonas vaginalis

Trichomonas vaginalis. Trophozoites in smear from culture (Giemsa's stain, oil immersion). Each of these trophozoites shows a large nucleus situated in the anterior end, the prominent stiff axostyle protruding beyond the posterior end, and four anteriorly directed flagella. The posteriorly directed flagellum courses along the margin of the undulating membrane and ends slightly posterior to the middle of the body.