Causative organism

Trichomonas vaginalis

A protozoan which infects the vagina, urethra and paraurethral glands.

Incubation period 5-28 days
How far trace back There is insufficient data to provide a definitive period, but current contact tracing and concurrent treatment is recommended to prevent reinfection.
Usual testing method Nucleic acid amplification tests (NAATs) are the most sensitive tests available to detect Trichomonas vaginalis. Wet preparation microscopy and culture are less sensitive
Common symptoms

10–50% of people are asymptomatic.

Vaginal symptoms: vaginal itch, vaginal discharge typically profuse malodorous (fishy odour) and frothy, and cervicitis.

Penile symptoms: are uncommon, but urethral discharge and dysuria occasionally occur

Likelihood of transmission per act of unprotected intercourse

Unknown, likely moderate to high

Perinatal transmission 5%

Likelihood of long-term sexual partner being infected Up to 70% of insertive partners in penis-in-vagina sex and 60-100% of receptive partners in penis-in-vagina sex
Protective effect of condoms High
Transmission by oral sex Extragenital infections (oral, anal) are uncommon
Duration of potential infectivity Trichomonas vaginalis in vaginal infections is thought to be longstanding, up to 3-5 years, whereas penile infections may spontaneously resolve lasting up to 4 months.
Important sequelae

Preterm delivery and low birth weight;

Increased transmission of HIV

Direct benefit of detection and treatment of contacts Cure
Usual management of contacts Counselling, clinical examination and testing. Treat sexual partners presumptively
Contact tracing priority Medium.

Only notifiable in the Northern Territory in Australia.

Not notifiable in New Zealand

Page last updated September 2022