Commonest trophozite infection by sexual intercourse -: (A) Entamoeba histolytica, (B) Trichomonas vaginalis, (C) Trepanoma palidium, (D) Giabrdia intestinales
Answer is B. Trichomoniasis has an estimated annual incidence of 173 million cases(Ref.PARK'S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE 21st Edition page no.304)