Gonorrhoea or gonorrhea, colloquially known as the clap, is a sexually transmitted infection (S.T.I.) caused by the bacterium Neisseria gonorrhoeae. Infection may involve the genitals, mouth or rectum. Infected men may experience pain or burning with urination, discharge from the penis, or testicular pain. Infected women may experience burning with urination, vaginal discharge, vaginal bleeding between menstrual periods, or pelvic pain. Complications in women include pelvic inflammatory disease and in men include inflammation of the epididymis. Many of those infected, however, have no symptoms. If untreated, gonorrhea can spread to joints or heart valves.