Trichomonas vaginalis is a parasite that causes vaginal and urethral infections. Trichomonas vaginalis is a typical sexually transmitted disease (STD). Vaginal contamination of Trichomonas vaginalis can either go undetected and show no symptoms ( asymptomatic carrier) or it can be detected by acute or chronic inflammation in the local area (genital discharge, pain and discomfort, etc.). The clinical manifestation of trichomonas vaginalis depends upon the agentâs virulence and a person's immunity. Men are usually asymptomatic carriers of trichomonas vaginalis. Trichomonas vaginalis can be detected in the vagina with a microbiological examination (in a native smear or with cultivation).