Short answer
Trichomoniasis (“trich”) is a common STI caused by a microscopic parasite.
It is frequently silent, reliably testable with molecular methods, and curable with clinician-directed prescription therapy. But partner treatment is non-negotiable, since untreated partners re-supply the infection within weeks.
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See Tests & Prices →Transmission in context
Trich spreads through vaginal sex; transmission via other routes is uncommon.
Condoms reduce risk.
Because male partners are so often silent, the infection ping-pongs between partners invisibly. Which is why simultaneous partner treatment defines cure as much as medication does.
Route context is covered in How Do Sexually Transmitted Infections Spread?.
Symptoms that overlap everything
Most infections cause no symptoms.
Possible signs include frothy or unpleasant-smelling discharge, genital itching or redness, burning with urination, and discomfort during sex.
In pregnancy, untreated trich is linked to preterm birth. Another reason testing plus treatment matters.
Discharge character alone never diagnoses: yeast, BV, chlamydia, and gonorrhea all mimic it, so symptoms trigger testing rather than conclusions.
Compare discharge patterns in Unusual Vaginal Discharge and STIs.
Testing and diagnosis that settles it
Molecular NAAT on vaginal swabs or urine is the sensitive standard; older wet-mount microscopy misses many infections.
Clinicians choose the sample by anatomy and availability, and pregnancy or persistence may add confirmatory retesting.
A negative test after the window period with no new exposure reliably clears the question.
Treatment and partner care principles
Clinicians prescribe current guideline-based therapy matched to the patient, including pregnancy-adjusted choices where relevant, with abstinence until completion and simultaneous partner treatment.
Return if symptoms persist: uncommon resistance is managed by specialists, while the usual cause is reinfection from an untreated partner.
The broader partner-treatment logic is covered in What Is Partner Notification for STIs?.
When to seek care
Seek care for discharge, itching, or burning; during pregnancy with any symptoms or exposure; and after a partner’s diagnosis.