Trichomonas

• A type of protozoa that cases vaginal and urethral infection.
• In NZ, unlike other STIs, Trichomonas is more common in women aged >25. It is also more commonly seen in those of Maori or Pacific ethnicity, and in areas of social deprivation.
• Up to 50% of women and the majority of men will be asymptomatic.
• Vaginal discharge is the commonest symptom, which may be malodourous and frothy. Also causes vulvovaginal itch, vulval dermatitis and post-coital bleeding.

Infection can persist for years in women if untreated.

• Test women with vaginal discharge or other vaginal and vulval symptoms.
• Not a recommended test for men with urethritis – reserved for persistent cases.
• It can take up to 2 weeks to test positive if infection occurs relating to specific sexual event.
• Male sexual contacts should be treated empirically rather than tested.

Request Trichomonas NAAT

NAAT/PCR on a low vaginal swab (self- or clinician-collected; chlamydia and gonorrhoea testing should be done also, and can be shared on same swab).

• A specific kit is usually required for NAAT testing e.g. the Aptima swabs/urine kit.
• Excellent sensitivity – a negative teston a well-collected sample makes the diagnosis very unlikely
• Excellent specificity – a positive testin an at risk person makes the diagnosis highly likely
• First void urine may also be used in women, but has lower sensitivity.

If testing in a male is required discuss with the clinical microbiologist first.

• Culture on a high vaginal swab is an acceptable alternative if NAAT/PCR is not available, however it is less sensitive and slower.
• Wet prep microscopy is no longer recommended due to limited sensitivity.

• Co-infection with other STIs is common.
• Test of cure is not required if symptoms resolve.
• If symptoms persist, or there are other exposures, don’t retest within 4 weeks of treatment, as the test may remain positive due to residual dead organisms.