1. Sexual transmission
Sexual behaviors, including kissing and touching, can spread STD and are the main route of transmission. Various pathogens such as Neisseria gonorrhoeae, HIV, Mycoplasma, Chlamydia, and Trichomonas vaginalis can be present in vaginal secretions and semen.
Sexual partners can be transmitted to each other through sexual behavior; while the pathogens of syphilis, genital herpes, and soft chancre are not present in semen, they can be transmitted through direct contact with the skin mucosa.
Women are more susceptible to sexually transmitted diseases than men. Those with too much prepuce are more susceptible to sexually transmitted diseases.
2. Non-sexual contact propagation
Sexually transmitted diseases have a large number of pathogens in the secretions, and indirect contact with clothes, utensils, articles, bedding, toilets, etc. contaminated by pathogen carriers or patients with urogenital secretions may also be infected.
3. Blood source transmission
AIDS, syphilis, gonorrhea, hepatitis B, hepatitis C, and cytomegalovirus infection can all be transmitted through blood transfusion.
Infusion of blood containing the above pathogens, the probability of infection can generally be as high as 95% or more, and the incubation period is short, the onset is fast, the symptoms are serious, and the complications are many. Whether hepatitis C can be transmitted through sexual contact is still inconclusive
4. Mother-to-child transmission
(l) Intra-fetal infection: Treponema pallidum, HIV, hepatitis B virus and herpes simplex virus can infect the fetus through the placenta, causing intra-fetal infection.
Fetal infections usually occur after 4 months of pregnancy. HIV can enter the amniotic cavity through the chorioamnion, and then enter the amnion fluid through the fetus, or directly through the mucosa, or the virus can pass through the placental syncytium trophoblast.
Syphilis infection through the placenta can cause fetal abortion, premature birth, stillbirth or death after birth. Even if the baby survives, there are often diseases such as deformity and mental retardation.
Herpes simplex virus transmission can cause fetal death, miscarriage, malformation, encephalitis, intrauterine growth retardation, cataract, congenital heart disease.
(2) Infection of the birth canal: Although some STDs cannot be transmitted through the placenta, infections can occur when the fetus passes through the birth canal, such as neonatal gonococcal ophthalmia, non-gonococcal infant conjunctivitis, neonatal pneumonia, etc. HIV can also infect the fetus through the maternal birth canal.
(3) Postpartum infection: Postpartum lactation and close contact between mother and baby can cause infection in infants. If the mother is HIV-infected, the baby can be infected by consuming human milk containing HIV.
5. Iatrogenic transmission
The equipment used in medical operations is not properly sterilized and can cause iatrogenic infections. Mainly unsterilized or incompletely sterilized syringes, surgical instruments, and other medical devices that pierce the skin or mucous membranes, causing the spread between patients, doctors and patients, especially the spread 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 are sometimes infected with sexually transmitted diseases after being raped.