Trichimonas vaginalis
is the single-celled protozoan that causes trichimoniasis, a sexually transmitted disease. Passed between sexual partners, Trichimonas may be asymptomatic in males but cause profuse vaginal discharge, burning, itching, and frequent urination in females.
Because Trichimonas moves with flagella, it is a member of the Mastigophora class. It has no cyst stage, existing only its motile, trophozoite (troph) stage. Stained Trichimonas are shown below at 1000 X magnification from a vaginal or urethral discharge. Each troph may possess three to five flagella at the anterior end. A single nucleus with a karyosome (appearing as a dark-staining dot in the center of the nucleus) is present.
Click on each image to see the enlarged version.
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