For 95-97% of cases, infection is resolved after one dose of metronidazole. Studies suggest that 4-5% of trichomonas cases are resistant to metronidazole, which may account for some “repeat” cases. Without treatment, trichomoniasis can persist for months to years in women, and is thought to improve without treatment in men. Women living with HIV infection have better cure rates if treated for 7 days rather than with one dose.
A draft sequence of the Trichomonas genome was published on January 12, 2007 in the journal Science confirming that the genome has at least 26,000 genes, a similar number to the human genome. An additional ~35,000 unconfirmed genes, including thousands that are part of potentially transposable elements, brings the gene content to well over 60,000.
^ McGregor, James A.; French, Janice I.; Parker, Ruth; Draper, Deborah; Patterson, Elisa; Jones, Ward; Thorsgard, Kyja; McFee, John (1995). "Prevention of premature birth by screening and treatment for common genital tract infections: Results of a prospective controlled evaluation". American Journal of Obstetrics and Gynecology. 173 (1): 157–167. doi:10.1016/0002-9378(95)90184-1. PMID 7631673.
Most people infected with Trichomonas vaginalis do not have any symptoms and can be undetected for years. Symptoms experienced include pain, burning or itching in the penis, urethra (urethritis), or vagina (vaginitis). Discomfort for both sexes may increase during intercourse and urination. For women there may also be a yellow-green, itchy, frothy, foul-smelling ("fishy" smell) vaginal discharge. In rare cases, lower abdominal pain can occur. Symptoms usually appear within 5 to 28 days of exposure. Sometimes trichomoniasis can be confused with chlamydia because the symptoms are similar.
Use condoms. Condoms are the best way to prevent STIs when you have sex. Because a man does not need to ejaculate (come) to give or get trichomoniasis, make sure to put the condom on before the penis touches the vagina, mouth, or anus. Other methods of birth control, like birth control pills, shots, implants, or diaphragms, will not protect you from STIs. Get tested. Be sure you and your partner are tested for STIs. Talk to each other about the test results before you have sex.