Syphilis is a sexually transmitted disease, or STD, caused by the Treponema pallidum bacteria. Less often, syphilis is transmitted from a pregnant woman to her baby. This form of syphilis is known as congenital syphilis.

What is going on in the body?

A person can develop syphilis 10 to 90 days after contact with the Treponema pallidum bacteria. Most people develop symptoms about 3 weeks after contact. This initial infection is known as primary syphilis.

If the Treponema pallidum bacteria are not effectively killed at this time, the person may develop secondary syphilis. This stage of the infection may show up right after the initial infection clears, or it may be delayed for several weeks.

If the syphilis is not treated effectively, the bacteria remains in the body. This period is known as latent syphilis. The Treponema pallidum bacteria travels to many vital organs. It may infect the brain, heart, eyes, nerves, and bones. Many years later, the person may develop tertiary syphilis.

What are the causes and risks of the infection?

Treponema pallidum is the cause of syphilis. The organism is spread from one person to another through direct contact with a syphilis sore. These sores are usually seen on the genitals or anus. However, they can also be found on the lips and inside the mouth. Therefore, syphilis can be spread by vaginal, anal, or oral sex. It can also be passed from a pregnant woman to her fetus.