Trichomoniasis

Trichomoniasis is caused by Trichomonas vaginalis, a microscopic single-celled parasite. It is the most common non-viral sexually transmitted infection globally, with an estimated 156 million new cases annually worldwide.

Despite being very common, trichomoniasis is rarely discussed and often not included in standard STI panels — which means many people carry and spread it unknowingly. The good news: it is completely curable with a single dose of metronidazole.

Symptoms appear 5–28 days after infection and are much more common in women than men:

• WOMEN: Frothy, yellow-green vaginal discharge with an unpleasant 'fishy' odour; itching, burning, redness, and soreness in and around the vagina; pain or burning during urination or sex.
• MEN: Most infections (70-80%) are completely asymptomatic. When symptoms occur: mild itching or irritation inside the penis; slight discharge; burning after urinating or ejaculating.

• Penis-to-vagina sex — the primary route
• Vulva-to-vulva sexual contact
• The parasite cannot infect the mouth or anus
• Theoretically can survive on wet surfaces briefly, though sexual contact is the primary route

• Wet mount microscopy — vaginal or urethral swab examined under microscope. Quick and inexpensive, but only 60-70% sensitive.
• NAAT (vaginal, cervical, or urethral swab) — 95-100% sensitivity; the preferred test in larger labs.
• Rapid antigen tests — available at some clinics.

You must specifically request a trichomoniasis test — it is often not included in standard STI panels.

• Metronidazole 2g — a single oral dose. Highly effective.
• Tinidazole 2g — an alternative single-dose option with fewer side effects.
• BOTH partners must be treated simultaneously to prevent immediate reinfection.
• Avoid alcohol for 24–48 hours after metronidazole (causes severe nausea and vomiting).
• Avoid sex for 7–10 days after treatment, or until both partners complete treatment.

• Any unusual vaginal discharge, especially frothy or foul-smelling
• Genital itching or irritation not explained by other causes
• Before or after a new sexual partner
• If a partner has been diagnosed with trich
• During pregnancy (associated with preterm birth)