There are no symptoms in the early and middle stages of latent syphilis. There is no symptom within 1 month of the incubation period, and the route of infection is mainly through sexual contact. Especially in untreated patients, the most infectious within 1 year after infection, generally the longer the course of treatment, the less infectious, after 4 years of infection, general contact is not infectious. In addition, the fetus can be infected during pregnancy or childbirth, kissing, towels, utensils, and blood transfusion can also be transmitted. The syphilis spirochete enters the body and is influenced by a variety of factors, the onset of the disease varies, but the syphilis process has a certain regularity, the initial site of infection is the genitals, often only one or several red papule nodules, the professional term is called syphilis hard chancre, no pain, even if broken, there is no pain.