Infection with the flagellate protozoan Trichomonas vaginalis is usually, but not exclusively, spread by sexual contact. The condition is commonly asymptomatic in males. In females trichomoniasis has a variety of manifestations, including vaginal discharge, irritation of the genitals, and pain during intercourse or urination. Both sexes may experience complications, such as cystitis and urethritis; males may also develop prostatitis and epididymitis. Treatment with metronidazole, an antibacterial and antiprotozoal agent, is standard.