• In women: may cause frothy yellow-green or thin vaginal discharge, unpleasant odor, itching/burning, pain when urinating, or discomfort during sex. Many people have no symptoms.
• In men: often no symptoms, but it can cause urethral irritation, burning after urination/ejaculation, or discharge.
• Diagnosis: a clinician can test a vaginal swab or urine sample, usually with a nucleic-acid test.
• Treatment: prescription oral antibiotics are needed, typically metronidazole. CDC guidance recommends metronidazole 500 mg by mouth twice daily for 7 days for women; men are often treated with a single 2 g oral dose. The correct regimen depends on sex, pregnancy, HIV status, prior treatment, and allergies. See the CDC trichomoniasis guideline.
• Partners must be treated at the same time, even if they have no symptoms. Avoid sex until everyone has completed treatment and symptoms have resolved.
• Women should be retested about 3 months after treatment because reinfection is common, per the CDC follow-up advice.

Morphology of Trichomonas vaginalis

• Exists only as a trophozoite. It has no cyst stage.
• Shape: pear-shaped or oval, with a pointed posterior end.
• Size: approximately 7-23 µm long and 5-15 µm wide.
• Nucleus: single, oval nucleus located near the anterior end.
• Flagella: five flagella:
  • Four anterior flagella project freely from the front.
  • One recurrent flagellum runs backward along the body.
• Undulating membrane: a short membrane formed along the anterior half of the organism by the recurrent flagellum.
• Axostyle: a prominent rod-like structure that runs through the body and projects from the posterior end.
• Motility: rapid, jerky or tumbling movement, demonstrable in a fresh saline wet mount.
• Cytostome: absent.