Trichomonas vaginalis

Trichomoniasis is the most common curable, non-viral sexually transmitted infection (STI) worldwide. It is caused by the single-celled protozoan parasite Trichomonas vaginalis (TV). In 2020, the World Health Organization (WHO) estimated 156 million new cases globally among individuals aged 15 to 49 years. Despite its prevalence, the true incidence remains unknown, as trichomoniasis is not a notifiable disease, except in the Northern Territory, and screening criteria are undefined. It has also been referred to as “the neglected STI” due to limited knowledge of its sequelae and associated costs.

Symptoms
- 70 to 80% of individuals experience minimal or no genital symptoms
- Men may present with urethritis, epididymitis or prostatitis
- Women may present with vaginal discharge, which can be profuse, malodorous or yellow-green
- In women with HIV, trichomoniasis is associated with an increased risk of pelvic inflammatory disease (PID)
Trichomonas vaginalis is associated with significant reproductive morbidity, including increased risk of preterm birth, premature rupture of membranes and small-for-gestational-age infants. Infection is also associated with a 1.5-fold increased risk of HIV acquisition.
Treatment
- Recommended: Metronidazole 400 mg orally with food, 12-hourly for 7 days.
- Alternative: Metronidazole 2 g orally with food, single dose (less effective).
- Avoid alcohol during treatment and for 24 hours after the last dose.
- Advise no sexual contact for 7 days after starting treatment, or until symptoms have resolved and the course is completed, whichever is later.
- Recommend treatment for the current sexual partner.
- Further guidance available at sti.guidelines.org.au
Test of Cure

Not recommended unless symptoms persist.
How to Order Trichomonas vaginalis Testing
Request Form Instructions:
- T. vaginalis PCR or Trichomonas PCR
Specimen Details (NSW):
- A high vaginal or endocervical swab.
- First-pass urine.
- A dedicated red-top dry swab or Aptima Unisex Swab kit.
- If routine vaginal bacterial culture is also required (MC&S), please provide a blue-top gel swab as well.
- Click here to view the current NSW swab guide.
Specimen Details (All Other States):
- A high vaginal swab or urethral swab is required.
- Use an orange dry swab for Trichomonas PCR testing, along with a blue gel swab for Microculture and Sensitivity.
- Testing for Trichomonas PCR is also available on urine samples.
Test Cost:
- Bulk-billed, subject to Medicare eligibility criteria.
Additional Resources:
- STI Doctor Brochure
- STI Patient Brochure