Trichomoniasis ("trich") is genuinely one of the most common curable STIs, and also one of the least discussed — largely because it's so frequently asymptomatic that a lot of people never realize it's a distinct, common infection at all.
What it is
Unlike most of the infections covered on this site, trichomoniasis is caused by a single-celled parasite, not a bacteria or virus. It's transmitted through sexual contact and is curable with antiparasitic medication, typically a single dose.
Why it goes unnoticed so often
Trichomoniasis is frequently asymptomatic, especially in men. When symptoms do occur — more commonly in women — they can include discharge, itching, or an unusual odor, but these overlap significantly with other, unrelated conditions like a yeast infection or bacterial vaginosis, which can delay someone connecting the symptoms to an STI at all rather than treating it as a routine irritation.
Why it's worth treating even when symptoms are mild
Left untreated, trichomoniasis is associated with increased susceptibility to other infections, including HIV if exposed. It's a real, treatable infection worth taking seriously even without dramatic symptoms — see our testing timing guide for when it's reliably detectable after a specific exposure.
Treatment and partners
Antiparasitic medication, prescribed after diagnosis, resolves the infection. As with bacterial STIs, current and recent partners typically need testing and treatment too, since continued sexual contact with an untreated partner leads to reinfection.
Frequently asked questions
Is trichomoniasis a virus or bacteria?
Neither — it's caused by a single-celled parasite, which is a genuinely different category from most other common STIs. It's treated with antiparasitic medication rather than a standard antibiotic or antiviral.
Why don't more people know they have it?
It's frequently asymptomatic, especially in men, and even when symptoms do occur in women (discharge, itching, odor) they can be mistaken for a yeast infection or bacterial vaginosis rather than recognized as an STI, which delays testing and treatment.
Does it increase risk from other infections?
Left untreated, it's associated with increased susceptibility to HIV if exposed, among other complications — another reason treatment matters even when symptoms are mild or absent.
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