Syphilis is a sexually transmitted disease caused by infection with the syphilis spirochete. After infection, the pathogen can invade various organs throughout the body, causing a variety of symptoms. As a classic sexually transmitted disease, syphilis is contagious, with its main routes of transmission being through sexual contact, mother-to-child transmission, and also through close contact, such as kissing, or the use of daily items from a syphilis patient, such as towels, razors, cutlery, etc. If syphilis is not treated, its infectivity gradually decreases over time.