Sexually transmitted diseases STD refers to a group of infectious diseases that can be transmitted through sexual contact, in China, people are referred to as venereal diseases, its concept is different from classical sexually transmitted diseases, inclusive of more than 20 diseases. According to the different pathogens of sexually transmitted diseases, it is divided into many types, caused by viruses, such as genital herpes caused by herpes simplex virus (HSV) (mainly caused by HSV-2), cytomegalovirus, type B, hepatitis A virus, human papillomavirus, human immunodeficiency virus, etc., caused by chlamydia, such as non-gonococcal urethritis caused by type D-K, lymphogranuloma venereum caused by type L, mycoplasma infection together, such as by ureaplasma urealyticum, mycoplasma hominis, Nongonococcal urethritis (cervic) caused by Mycoplasma genitalium infection, bacterial infections such as gonorrhoea caused by Choderma gonorrhoeae infection, and sexually transmitted diseases infected by fungi, protozoa, body surface parasites, and spirochetes as pathogens.