Which statement best describes Trichomonas vaginalis infection in women and men, and the preferred diagnostic method?

• A. Women: vaginitis with foul-smelling discharge; men: asymptomatic or mild urethral irritation; diagnosis by NAAT or wet mount.
• B. Women: vaginitis with foul-smelling discharge; men: asymptomatic; diagnosis by serology.
• C. Women: vaginitis with itching and discharge; men: severe urethritis; diagnosis by culture.
• D. Women: asymptomatic; men: urinary symptoms; diagnosis by stool antigen

Answer: (A)

Trichomonas vaginalis infection typically presents in women as vaginitis with a foul-smelling discharge, while men are often asymptomatic or have only mild urethral irritation. For diagnosis, nucleic acid amplification tests (NAAT) on appropriate specimens (such as a vaginal swab or first-void urine) are preferred because they are highly sensitive and can detect infection even when symptoms are absent. Wet mounts can detect the parasite when it's present, but their sensitivity is much lower, so relying on NAAT reduces the chance of missed infections. This combination of a characteristic clinical picture plus the most reliable testing method makes the described statement the best fit.