Trichomoniasis

Overview

In Australia, trichomonas is more common in older people, people from regional and remote areas, especially Aboriginal and Torres Strait Islander people and street-based sex workers.
Uncommon cause of vaginal discharge or penile urethritis in urban settings.
Long natural history (years) if not treated.
Without treatment, the infection is cleared more quickly in a penis than in a vagina.

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

Symptoms
Urethritis – usually asymptomatic. See chlamydia for more information. Urethral discharge (uncommon) Dysuria (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 and low birth weight. Post-partum sepsis

Special considerations

Up to 50% of vaginal infections are asymptomatic; urethral infections are usually asymptomatic.
May enhance human immunodeficiency virus (HIV) transmission.

Testing is not routinely recommended for people with urethritis.
Screening is not recommended except in high prevalence populations; refer to local guidelines.
Treat contacts presumptively.

Site/Specimen	Test	Consideration
High vaginal swab	NAAT	Preferred option in people with a vagina. Should ideally be clinician collected if the patient is symptomatic but can be self-collected if client declines examination.
First pass urine (FPU)	NAAT	Available in major laboratories in each state.

NAAT – Nucleic Acid Amplification Test

Specimen collection guidance

Clinician collected | Self-collection

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

Treatment advice

Re-infection and poor adherence should be ruled out in persistent or recurrent infection.
Seek specialist advice if suspected metronidazole resistance or contraindication.
Avoid alcohol with metronidazole treatment and for 24 hours thereafter.

Other immediate management

Advise no sexual contact for 7 days after treatment is commenced, or until the course is completed and symptoms resolved, whichever is later.
Recommend that their current sexual partner is treated.
Contact tracing.
Provide patient with factsheet.
Trichomoniasis is only a notifiable condition in the Northern Territory.

Special considerations

Consider seeking specialist advice before treating any complicated presentation.

Situation	Recommended
Pregnancy	Category B2 in pregnancy
Breastfeeding	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 living with HIV	Reports indicate single-dose metronidazole is less effective than extended metronidazole.

There is currently insufficient data to provide a definitive period for contact tracing, focus on current and recent partners.
Test from genital sites.
Consider presumptive treatment if there has been sexual contact within the past 2 weeks or when the person’s individual circumstances mean later treatment may not occur.
Partners with a penis may test negative for trichomonas as it is more likely to resolve spontaneously in these people.

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.
Educate about condom use, contraception, HIV PrEP/PEP, safe injecting practices, consent, CST and vaccinations for HAV, HBV and HPV as indicated.

Test of cure

Not recommended unless symptoms persist.

Retesting

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.

100% of vaginal infections diagnosed are treated with recommended principal treatment option

Dize L, Agreda P, Quinn N, Barnes MR, Hsieh YH, Gaydos CA. Comparison of self-obtained penile-meatal swabs to urine for the detection of C. trachomatis, N. gonorrhoeae and T. vaginalis. Sex Transm Infect 2013;89:305-7.
Lusk MJ, Naing Z, Rayner B, Rismanto N, McIver CJ, Cumming RG, et al. Trichomonas vaginalis: underdiagnosis in urban Australia could facilitate re-emergence. Sex Transm Infect 2010;86:227-30.
British Association for Sexual Health and HIV (BASHH). Trichomonas vaginalis. Available at: https://www.bashh.org/guidelines (last accessed 24 October 2021).

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