Sexually transmitted diseases (STDs) are a group of infectious diseases that can be transmitted through sexual contact, and in our country are referred to as STDs. The concept is different from the classical STD and includes more than 20 types of diseases. The term “sexually transmitted” does not necessarily refer to genital intercourse. Sexual transmission is a form of transmission that can be direct or indirect, and can also be transmitted from parent to fetus or newborn. Venereal disease (VD) is a systemic disease transmitted through sexual intercourse with obvious symptoms of genital damage, also known as a classical STD. They include syphilis, gonorrhea, chancre and venereal lymphogranuloma. Sexually transmitted diseases are a group of infectious diseases that can be transmitted through sexual contact, and in China, they are referred to as STDs. The concept is different from the classical STDs and includes more than 20 types of diseases. The pathogens that can be transmitted by sexual means and caused by STD 1, superficial fungus: ringworm; 2, protozoa, Trichomonas vaginalis: trichomoniasis, urethritis; 3, amoeba lysis: amoebiasis; 4, Giardia lamblia: Giardia lamblia infection; 5, body parasites, pubic lice: pubic lice disease; 6, scabies mites: scabies in the pubic area. The “STD Control Management Measures” stipulates that there are 8 kinds of STDs that are currently the focus of control in China. These are syphilis, gonorrhea, AIDS, soft chancre, venereal lymphogranuloma, non-gonococcal urethritis, condyloma acuminata and genital herpes. The first three of them belong to Class B infectious diseases managed by the Law of the People’s Republic of China on the Prevention and Control of Infectious Diseases, while the other five are diseases subject to surveillance and outbreak reporting by the Ministry of Health. Sexually transmitted disease transmission 1, the sexual route of transmission: including kissing, touching, including sexual behavior can be transmitted STD, is the main route of transmission. The pathogens such as Neisseria gonorrhoeae, HIV, Mycoplasma, Chlamydia and Trichomonas vaginalis can be found in vaginal secretions and semen, and one of the sexual partners can infect the other through sexual intercourse. The actual fact is that women are more likely to be infected with STDs than men. The person who is circumcised is more likely to be infected with STDs. 2, non-sexual contact transmission: STD patients have a large number of pathogens in the secretions, indirect contact with the pathogen carrier or patient urogenital secretions contaminated clothing, utensils, articles, bedding, commode, etc., may also be infected. 3, blood-borne transmission: AIDS, syphilis, gonorrhea, hepatitis B, hepatitis C, cytomegalovirus infection can be transmitted through blood transfusion. Transfusion of blood containing the above pathogens, the chance of infection can generally be as high as 95% or more, and the incubation period is short, the onset is rapid, the symptoms are severe, and there are many comorbidities. There is no definitive answer as to whether hepatitis C can be transmitted through sexual contact. 4, mother-to-child transmission: (1) intrauterine infection: syphilis spirochetes, HIV, hepatitis B virus and herpes simplex virus can be transmitted to the fetus through the placenta, resulting in intrauterine infection. Fetal infection usually occurs after the fourth month of gestation. HIV can cross the chorionic amniotic membrane into the amniotic cavity and then infect the fetus through the intestinal tract by swallowing amniotic fluid, or directly through the mucous membranes, or through the placental syncytial trophectoderm through the blood. Syphilis infection through the placenta can cause miscarriage, premature birth, stillbirth or death after birth, and even if the baby survives, it often has deformities, mental retardation and other diseases. Herpes simplex virus fetal transmission can cause fetal death, miscarriage, malformation, encephalitis, intrauterine growth retardation, cataract, congenital heart disease, etc. （HIV can also infect the fetus through the maternal birth canal. (3) Postpartum infection: Postpartum breastfeeding and close contact between mother and infant can cause infection in infants. If the mother is HIV-infected, the baby can be infected by consuming HIV-containing breast milk. 5) Medical transmission: Inadequate sterilization of instruments used in medical operations can cause medical infections. Mainly unsterilized or incompletely sterilized syringes, surgical instruments, and other medical devices that pierce the skin or mucous membranes can cause transmission between patients and between doctors and patients, especially the transmission of AIDS, hepatitis B and hepatitis C. 6. Artificial insemination, organ transplantation and sexual violence: Artificial insemination and organ transplantation can cause the spread of STD, especially HIV. Children or adults can sometimes contract STD after being raped. Prevention of sexually transmitted diseases 1, STD prevention and control policy: many social factors greatly affect the occurrence, spread and prevalence of STD, so the prevention and control of STD is a difficult and complex social system project. China’s “management of STD prevention and control measures” clearly pointed out that China’s prevention and control of STD to implement prevention-oriented, combined with prevention and treatment, comprehensive management of the policy. Health and medical departments alone is not enough, must be combined with the construction of socialist spiritual civilization, strengthen the legal education, mobilize the whole society to participate in the formation of multi-sectoral division of labor and cooperation under the leadership of the government at all levels, each of their responsibilities, close cooperation, and concerted efforts to control the disease network, in order to effectively control the epidemic. 2.STD prevention: STD prevention contains two levels of content, one is to protect healthy people from infection, which is often referred to as primary prevention of STD; the second is to follow up STD patients and suspected patients, and strive for early detection, early diagnosis and correct treatment, so as to avoid complications and sequelae in the late development of the disease, as well as to prevent further infection to the surrounding healthy people to form the second generation of infection, that is, secondary prevention. (1) Primary prevention of sexually transmitted diseases (STD) To popularize the knowledge of STD prevention and treatment, different health education models should be adopted for different groups of people. Through health education, people should be fully aware of the hazards and preventability of STD and know how to protect themselves from infection. ① Strictly prohibit impure sexual behavior: Adhere to the ethical concept of monogamy and strictly prohibit impure sexual behavior. In particular, avoid having sex with people who belong to high-risk groups. For example, the rectal epithelium is more delicate than the vaginal epithelium, and anal sex is more likely to cause damage to the mucosa than vaginal sex and increase the risk of STD infection. ②Use condoms: For those who refuse to change their high-risk sexual behavior, we should promote the correct use of condoms every time they have sex. ③Avoid pregnancy: It is very important to strengthen the screening for STD infection in pregnant women, and it should be included as a routine screening program. Syphilis, gonorrhea, AIDS, cytomegalovirus infection and genital herpes can be transmitted to the fetus through the placenta. In addition, gonorrhea, non-gonococcal cervicitis, genital herpes and condyloma acuminata can also cause infection of the newborn through the birth canal. Blood transfusion and the use of blood products are important ways to transmit HIV, hepatitis B, hepatitis C, syphilis and cytomegalovirus infection. According to the relevant regulations, blood donors must be tested for HIV antibody, hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (anti-HCV), syphilis seropositivity and other items before supplying blood, and only those with all negative tests are allowed to supply blood. Although transfusion of blood that has passed the test is basically safe, it is not 100% safe and reliable. Because there is a certain interval (window period) between the infection of any infectious disease and the detection means currently used to prove the infection, at this time, although the test is negative, but the infectiousness exists, and then due to the quality of reagents and many factors, there may be false negatives, so the clinical work should try to avoid blood transfusion. For the same reason, blood products that fail to detect pathogenic contamination of raw materials (plasma), once put into production, will contaminate a large amount of plasma, and therefore produce blood products with a greater range of transmission, so the use of blood products should also be more vigilant. ⑤ Application of antimicrobials and local disinfectants: Although taking antimicrobials before or after sexual intercourse can be useful in preventing some STDs. However, it is not reliable for sexually promiscuous persons, prostitutes, and clients to protect themselves from infection by using antimicrobials given afterwards or by injection for STD. No single antimicrobial can prevent all STDs, especially viral STDs such as AIDS, genital herpes, and condyloma acuminata, for which there is no specific treatment. Repeated use of antimicrobials can also lead to drug resistance and secondary infections, which can have adverse effects. Topical disinfectants, even if they contain real disinfectants and ensure the concentration and duration of action, at best only kill the pathogens already present on the surface of the skin and mucous membranes, but it is difficult to ensure that the pathogens are discharged from the deeper part of the lesion, tissue or organ at any time. Users also tend to believe or rely too much on its disinfection effect and ignore other prevention methods. (2) Secondary prevention of sexually transmitted diseases Patients with STDs should be diagnosed and treated correctly in a timely manner. there are many types of STDs and many types of pathogens that cause STDs. Especially for STD caused by virus, there is still no specific treatment drug. The clinical features of some different types of STDs have many similarities, and because of the frequent occurrence of mixed infections and atypical cases, multiple tests must be used to clarify the diagnosis. Most patients stop treatment once their symptoms are relieved or disappear, do not complete the full course of treatment, or blindly use drugs, making the treatment incomplete and become chronic, which makes further treatment difficult. Therefore, it is important to diagnose STD in a timely manner and to treat it effectively and thoroughly. Almost all STDs do not develop protective immunity for a longer period of time due to a single infection, so they can be re-infected and develop again after treatment. Close contacts should be treated prophylactically to break the chain of infection as early as possible. Follow-up of sexual partners and treatment of couples together. Clinicians should try to convince patients to notify all their sexual partners or their spouses for screening and necessary treatment of STD infection, emphasizing that couples should be investigated and treated together in order to eliminate the source of infection and prevent circular transmission. STD patients should be prohibited from having sex until they are cured, or at least they should use condoms for safe sex to prevent further spread of the disease. 3, do a good job of consultation of patients with STDs: clinicians in addition to giving patients timely diagnosis and treatment, but also do a good job of consultation. The main aspects are: mobilize sexual partners or spouses to seek timely medical treatment; suggest and guide patients to receive HIV antibody testing; correct use of condoms; do a good job of publicity, do not believe in street medicine advertising; persuade them to stop high-risk sexual behavior; prevent intra-family contact transmission. 4, STD patients after treatment follow-up: for example, syphilis should be done every 3 months within a year after the completion of formal treatment, and every 6 months in the second year for non-syphilis spirochete antigen syphilis serology test (RPR or USR, etc.), gonorrhea formal treatment after the 7-10 days and 14 days before and after the gonorrhea culture, etc., to evaluate the effectiveness of treatment and prevent recurrence.