Trichomoniasis

Caused by Trichomonas vaginalis, a protozoan which infects the vagina, urethra and paraurethral glands.

In Australia, trichomonas is more common in older women and women from regional and remote areas, especially Aboriginal and Torres Strait Islander women. Uncommon cause of vaginal discharge or male urethritis in urban settings.

Clinical presentation

	Male	Female
Symptoms	Usually asymptomatic (see Chlamydia for a comparable picture); urethral discharge and dysuria are both uncommon	Malodourous vaginal discharge, typically profuse and frothy; vulval itch/soreness; cervicitis
Complications	Associated with prostatitis	Associated with premature rupture of membranes, pre-term delivery, low birth weight and postpartum sepsis

Up to 50% of vaginal infections are asymptomatic; urethral infections are usually asymptomatic. May enhance HIV transmission.

Diagnosis

High vaginal swab NAAT is the preferred option in people with a vagina, and should ideally be clinician-collected during pelvic examination if symptomatic, but can be self-collected if the patient declines examination. First-pass urine NAAT is also available in major laboratories in each state, and is the test to use in men. A wet-prep high vaginal swab can also detect the organism, but its sensitivity is poor compared with NAAT.

Testing is not routinely recommended for men with urethritis — treat male contacts presumptively instead.

Management

Situation	Recommended	Alternative
Uncomplicated infection	Metronidazole 400mg PO with food, BD for 7 days	Metronidazole 2g PO with food, stat

Avoid alcohol with metronidazole treatment and for 24 hours thereafter.

Advise no sexual contact for 7 days after treatment is commenced, or until the course is completed and symptoms resolved, whichever is later — and until the current partner has been treated. Recommend that the current sexual partner is treated presumptively.

There is no fixed contact-tracing period; focus on current and recent partners and use clinical judgement. Trichomoniasis is only a notifiable condition in the Northern Territory.