Syphilis is mainly contagious in the early stages, syphilis has a long course, and in the late stages syphilis is basically not contagious. Untreated patients are generally strongly contagious within 1-2 years after infection, with the prolongation of the disease period, the contagiousness becomes smaller and smaller, more than 10 years after infection, basically patients are not contagious. Syphilis can be divided into three stages, generally in the first stage, the second stage is more infectious, the third stage, although damage to various organs, the disease is more serious, but less infectious. Syphilis is mainly transmitted through sexual contact, and in China, syphilis infections transmitted through sexual contact account for more than 95% of the total number of infections. In addition, it is vertically transmitted from mother to child. After the fourth month of pregnancy, pregnant women can transmit syphilis spirochetes to the fetus through the placenta and umbilical vein, and also during delivery.