Syphilis is infection with the bacteria Treponema pallidum.

Syphilis is a sexually-transmitted infectious disease. The bacteria that cause it spread through broken skin or mucous membranes.

Pregnant mothers infected with the disease can pass it to the baby developing in their womb. This is called congenital syphilis.

Syphilis is widespread in the United States. It mainly affects sexually active adults ages 20 to 29.

Syphilis has several stages.

• Primary syphilis is the first stage. Painless sores ( chancres) form at the site of infection about 2-3 weeks after you are first infected. You may not notice the sores or any symptoms, particularly if the sores are inside the rectum or cervix. The sores disappear in about 4-6 weeks, even without treatment. The bacteria become dormant (inactive) in your system at this stage. For more specific information about this type of syphilis, see primary syphilis.
• Secondary syphilis occurs about 2-8 weeks after the first sores form. About 33% of those who do not have their primary syphilis treated will develop this second stage. These symptoms will often also go away without treatment and again, the bacteria become dormant (inactive) in your system. For more specific information about this type of syphilis, see secondary syphilis.
• Tertiary syphilis is the final stage of syphilis. The infection spreads to the brain, nervous system, heart, skin, and bones. The dormant bacteria may be detectable either by seeing the damage they cause to a part of the body, or through a blood test for syphilis. For more specific information about this type of syphilis, see tertiary syphilis.