Syphilis is a chronic, systemic sexually transmitted disease caused by pale (syphilis) spirochetes. It is mainly transmitted through sexual channels. It can be clinically characterized as primary syphilis, secondary syphilis, tertiary syphilis, latent syphilis and congenital syphilis (fetal syphilis).
Syphilis is prevalent throughout the world. According to WHO estimates, there are about 12 million new cases worldwide each year, mainly in South Asia, Southeast Asia and sub-Saharan Africa. In recent years, syphilis has grown rapidly in China and has become the most common sexually transmitted disease reported. Among the reported syphilis, latent syphilis is the majority, and primary and secondary syphilis are also more common, and the number of reported cases of congenital syphilis is also increasing.