Q: What is trichomoniasis, and how is it spread?
A: Trichomoniasis is one of the most common sexually transmitted infections, with about 4 million new cases in the U.S. annually, most of them in women. The cause is a protozoan parasite, Trichomonas vaginalis, which infects the vagina and sometimes the urethra and is transmitted during unprotected sex. Contrary to some online reports, it is not spread by toilet seats (largely because the organism can’t live long on objects).
Two-thirds of people with trichomoniasis have no symptoms so they usually don’t know it, but they can still spread the infection. Common symptoms in women are vaginal itching, irritation, greenish-yellowish vaginal discharge, and pain and itching during intercourse or urination—which can be mistaken for symptoms of other vaginal or cervical infections. The great majority of infected men have no symptoms; the most common symptom in men is a burning sensation when urinating.
The most serious risks of trichomoniasis are complications during pregnancy, reduced fertility, and increased risk of getting other sexually transmitted infections.
If you’re a woman having symptoms of a vaginal infection, including any abnormal discharge, consult your health care provider, who can do a lab test. And if you’re taking medication for a yeast infection and there’s no improvement in three days, get medical advice.
A single dose of antibiotics can cure trichomoniasis. Your sexual partner(s) should also be treated in order to prevent re-infection, which is common. Condom use greatly reduces the risk of infection. For more information, go to the CDC's trichomoniasis web page.
See also: How to Prevent STDs.