Trichomoniasis is an infection spread through sexual contact. It is caused by the microscopic organism Trichomonas vaginalis. It infects the urethra of both women and men. Other sites of infection in women include the vagina, cervix, and Bartholin glands found at the vaginal opening.

Men often do not have symptoms when infected with Trichomonas. Some women also have no symptoms. They can harbor the organism for prolonged periods without knowing it. It is often not possible to tell when a woman became infected and who may have transmitted the infection to her. When symptoms occur, the most common is a moderate, thin, irritating vaginal discharge. The discharge may have an unpleasant odor. A woman may feel a burning sensation when urination and having intercourse.

The infection is treated with the antibiotic metronidazole. It is important that the woman's sexual partners also receive treatment -- even if they have no symptoms. Avoid sexual activity until treatment is complete, otherwise there is a high rate of reinfection.