sexual intercourse 3 =Infective Stage Diagnostic Stage Trichomonas vaginalis 阴道毛滴虫 ①Trophozoe in Multiplies by longitudinal 3 Trophozoite in vaginal and prostatic binary fission vagina or orifice secretions and urine of urethra 单宿主型一单一阶段单宿主型——单一阶段