Syphilis

Definition:

A sexually transmitted or congenital infection caused by the bacterium Treponema pallidum. See also documents on Syphilis; primary, Syphilis; secondary, and Syphilis; tertiary.

Causes, incidence, and risk factors:

Syphilis is an infectious disease caused by the spirochete Treponema pallidum, which penetrates broken skin or mucous membranes. Transmission occurs most frequently by sexual contact. Syphilis can also be transferred to the fetus via the placenta after the 10th week of pregnancy. Syphilis has 3 stages. In the primary stage, painless sores, called chancres, appear 10 days to 6 weeks after exposure which can disappear on their own. The secondary stage can begin a week to 6 months after the primary stage. A skin rash is the hallmark of this stage, and lesions may appear again. The lesions are very infectious in this stage. A latent or tertiary phase follows during which no symptoms are present, but syphilis can be diagnosed by blood tests. If the disease has not been effectively treated, bacteria continue to invade the body, and there will be a relapse. The tertiary phase is a widespread infection that infects the internal organs, bones, the heart, and the brain. Approximately 30,000 cases of syphilis in adults are reported each year in the U.S. Congenital syphilis occurs in 1:10,000 live births. Transplacental transmission of syphilis can result in stillbirth. The risk of transmission to the fetus in untreated primary or secondary syphilis is approximately 100%.