Trichomonas vaginalis

Trichomonas vaginalis. Trophozoites in vaginal smear (Papanicolaou stain, oil immersion). Several trophozoites are seen to be linearly arranged in this field. The middle organism that stains more darkly demonstrates a fine flagellum extending from it. Two of the trophozoites to the right of this flagellated trophozoite demonstrate characteristic red granules (hydrogenosomes), whereas they are less clear in the other organisms. The variable morphology and size of these trophozoites illustrate the difficulty in recognizing them in Papanicolaou stained smears.