Trichomoniasis (trich) is an infectious disease caused by the parasite Trichomonas vaginalis.[2] About 70% of women and men do not have symptoms when infected.[2] When symptoms do occur they typically begin 5 to 28 days after exposure.[1] Symptoms can include itching in the genital area, a bad smelling thin vaginal discharge, burning with urination, and pain with sex.[1][2] Having trichomoniasis increases the risk of getting HIV/AIDS.[1] It may also cause complications during pregnancy.[1]
For 95-97% of cases, infection is resolved after one dose of metronidazole.[26][35] Studies suggest that 4-5% of trichomonas cases are resistant to metronidazole, which may account for some “repeat” cases.[33][9] Without treatment, trichomoniasis can persist for months to years in women, and is thought to improve without treatment in men.[9] Women living with HIV infection have better cure rates if treated for 7 days rather than with one dose.[31][36]
Evidence from a randomized controlled trials for screening pregnant women who do not have symptoms for infection with trichomoniasis and treating women who test positive for the infection have not consistently shown a reduced risk of preterm birth.[29][30] Further studies are needed to verify this result and determine the best method of screening. In the US, screening of pregnant women without any symptoms is only recommended in those with HIV as trichomonas infection is associated with increased risk of transmitting HIV to the fetus.[31]
People who have been treated for trichomoniasis can get it again. About 1 in 5 people get infected again within 3 months after receiving treatment. To avoid getting reinfected, all sex partners should get treated with antibiotics at the same time. Wait to have sex again until everyone has been treated and any symptoms go away (usually about a week). Get checked at 3 months to make sure you have not been infected again, or sooner if your symptoms come back before then.
Trichomoniasis (trich) infection is spread when you have sex with an infected partner. Many women and most men do not have any symptoms of trich. If symptoms appear, they usually start within 1 week after a person is infected. But it may take up to a month for symptoms to appear. In most cases, trich should be treated to prevent transmitting this sexually transmitted infection (STI) to others and to prevent some problems that can happen if you are pregnant. You and your sex partner(s) should be treated for trich at the same time, to avoid reinfecting each other.
The parasite passes from an infected person to an uninfected person during sex. In women, the most commonly infected part of the body is the lower genital tract (vulva, vagina, cervix, or urethra). In men, the most commonly infected body part is the inside of the penis (urethra). During sex, the parasite usually spreads from a penis to a vagina, or from a vagina to a penis. It can also spread from a vagina to another vagina. It is not common for the parasite to infect other body parts, like the hands, mouth, or anus. It is unclear why some people with the infection get symptoms while others do not. It probably depends on factors like a person’s age and overall health. Infected people without symptoms can still pass the infection on to others.

The advent of new, highly specific and sensitive trichomoniasis tests present opportunities for new screening protocols for both men and women.[24][27] Careful planning, discussion, and research are required to determine the cost-efficiency and most beneficial use of these new tests for the diagnosis and treatment of trichomoniasis in the U.S., which can lead to better prevention efforts.[24][27]