• In Australia, trichomonas is more common in older women and women from regional and remote areas, especially Aboriginal & Torres Strait Islander women
  • Uncommon cause of vaginal discharge or male urethritis in urban settings
  • Long natural history (years) if not treated in women
  • Without treatment, the infection is cleared more quickly in men than women.


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

Clinical presentation

Male Female
Usually asymptomatic. See chlamydia for more information Malodourous vaginal discharge - typically profuse and frothy
Urethral discharge (uncommon) Vulval itch/soreness
Dysuria (uncommon) Cervicitis
Associated with prostatitis Associated with premature rupture of membranes, pre-term delivery and low birth weight
  Post-partum sepsis

Special considerations

  • Up to 50% of infected women are asymptomatic, men are usually asymptomatic.
  • May enhance HIV transmission.


  • Testing is not routinely recommended for men with urethritis
  • Treat male contacts presumptively.
Diagnosis in males

FPU Available in major laboratories in each state
NAAT – Nucleic Acid Amplification Test
FPU – First pass urine
Diagnosis in females

High vaginal swab or FPU

High vaginal swab should ideally be clinician collected during pelvic examination but can be self-collected if client declines examination.

High vaginal swab (wet prep)

TV can be found on a high vaginal swab (wet prep) by the laboratory if TV is requested. However this test has poor sensitivity compared to NAAT testing.

NAAT – Nucleic Acid Amplification Test
FPU – First pass urine

Specimen collection

Clinician collected |


  • NAAT testing for Trichomonas vaginalis  is currently available through some private pathology companies and the following laboratories:
    • NSW: SydPath, St Vincent’s PathologyDarlinghurst & Pathology West – ICPMR, Westmead Hospital, Westmead 
    • QLD: QML Pathology, Brisbane & Queensland Pathology
    • SA: SA Pathology, Adelaide 
    • VIC: Core Laboratory, The Royal Women’s Hospital, Melbourne
    • WA: PathWest Laboratory, Queen Elizabeth II Medical Centre, Perth 
  • Cervical screening (Pap smear) and urine or high vaginal samples may report trichomonas but these results must be confirmed by NAAT before initiating treatment 
  • Cervical screening alone is not diagnostic of trichmonas 


Principal Treatment Options
Uncomplicated infection

Metronidazole 2g PO with food, stat.
Tinidazole 2g PO stat. 

Metronidazole 400mg PO with food, BD for 5 days.

Treatment advice

  • Reinfection and poor adherence should be ruled out in persistent or recurrent infection
  • Treatment failures with single-dose metronidazole should trial single dose tinidazole or extended metronidazole therapy
  • High-level metronidazole resistance has been reported, although incidence is believed to be low. Reports indicate successful treatment with extended doses of oral or intra vagina tinidazole for these patients – discuss with local sexual health clinic
  • Avoid alcohol with metronidazole and tinidazole treatment and for 24 hours thereafter.

Other immediate management

  • Advise no sexual contact for 7 days after treatment is administered and their current sexual partner is treated
  • Contact tracing
  • Provide patient with factsheet
  • Trichomoniasis is only a notifiable condition in the NT.

Special treatment situations

Special considerations

  • Single-dose treatments are advised.
  • Consider seeking specialist advice before treating any complicated presentation.
Pregnant women 
Due to conflicting outcomes of treating in pregnancy, seek specialist advice
Breastfeeding Consider intravaginal treatment. Metronidazole may affect taste of breast milk; avoid high doses in breastfeeding.
Allergy to principal treatment choice There is no effective alternative to 5 nitroimidazole compounds.
Metronidazole desensitisation has been described
People who are HIV positive Reports indicate single-dose metronidazole is less effective than extended metronidazole.

Contact tracing

  • For all sexual partners
  • There is currently insufficient data to provide a definitive period for this, partner treatment encouraged presumptively.

See Australasian Contact Tracing Manual - Trichomoniasis for more information.

Follow up

Review in 1 week provides an opportunity to:

  • Confirm patient adherence with treatment and assess for symptom resolution
  • Confirm contact tracing procedures have been undertaken or offer more contact tracing support
  • Provide further sexual health education and prevention counselling.

Test of Cure (TOC)

Not recommended.


  • For patients who remain symptomatic or where partner treatment remains uncertain, retesting should be performed after 4 weeks
  • This also provides the opportunity to retest, post the window period, for other STIs.

Auditable outcomes

100% of women diagnosed are treated with recommended principle treatment option.


  • Dize, Laura. Agreda, Patricia. Quinn, Nicole. Barnes, Mathilda R. Hsieh, Yu-Hsiang. Gaydos, Charlotte A. Comparison of self-obtained penile-meatal swabs to urine for the detection of C. trachomatis, N. gonorrhoeae and T. vaginalis. Sexually Transmitted Infections. 89(4):305-7, 2013 Jun.
  • Lusk, Josephine. Naing, Zin. Rayner, Ben. Rismanto, Nikolas. McIver, Christopher. Cumming, Robert. McGeechan, Kevin. Rawlinson, William. Konecny, Pam. Trichomonas vaginalis: underdiagnosis in urban Australia could facilitate re-emergence. Sex Transm Infections. 86:227-230, 2010.
Last Updated: Thursday, 29 March 2018