Trichomoniasis is a sexually transmitted infection (STI) caused by a parasite called Trichomonas vaginalis. It is one of the most common curable STIs in the world.
Anyone who is sexually active can get trichomoniasis, but it is more common in women than in men. Women can get trichomoniasis from having unprotected sex with an infected partner. Trichomoniasis can also be passed from a mother to her baby during childbirth.