Trichomoniasis is an inflammatory disease of the urogenital organs or the intestines, caused by [Trichomonas vaginalis], a flagellate protozoon. It is usually transmitted by sexual intercourse, and causes vaginitis, a superficial ulceration, itching, inflammation and a gray or yellow-green discharge. Urination may be painful. It may also occur in animals, causing miscarriages and sterility in cows (and resultant economic loss); poultry are also affected.
It has been estimated that about 20% of the female population of the USA is affected. The infection is more prevalent in institutionalized patients and lower socio-economic classes than in other groups.