Trichomoniasis is a genitourinary infection by a parasitic protozoan Trichomonas vaginalis, one species of zooflagellate
protozoa that are common parasites in the digestive system of animals. (Two other species found in humans are T. buccalisa and T. hominis, nonpathogenic forms located in the mouth and intestine, respectively.) Trichomoniasis, a sexually transmitted disease, generally occurs in the vagina but may also be found in the urethra and bladder in either sex and in the prostrate gland in males, who can serve as carriers. Trichomoniasis is treated with antibiotics. To avoid reinfection, both partners must be treated simultaneously. Vaginal
symptoms include itching, burning, and an irritative
discharge; urethral symptoms are painful urination and a mild discharge. Some women may have no symptoms.