Treponema pallidum (Syphilis)

About 12 million people worldwide are infected with syphilis and > 90% of cases are in developing countries. Syphilis can spread through sexual contact or in pregnancy (mother to fetus), however, it can be effectively treated with antibiotics. Without treatment, an infection can lead to serious consequences including small tumors (called gummas), neurological problems (stroke, meningitis, deafness, dementia), cardiovascular disease, and an increased risk of HIV infection (2-5x). An infected baby can also develop serious problems such as cataracts, deafness, seizures, or death. It has been reported that untreated early syphilis in pregnant women results in perinatal death in up to 40% of cases. If acquired during the 4 years before pregnancy, it can lead to infection of the fetus in 80% of cases.

The signs and symptoms of syphilis vary depending on which of the four stages it presents (primary, secondary, latent, and tertiary). During the first (primary) stage of syphilis, a sore appears at the point of contact where syphilis was transmitted. The sore is usually painless, lasts 3-6 weeks, and heals without treatment. Secondary syphilis occurs approximately 4-10 weeks after the primary infection and usually starts with a rash on one or more areas of the body (and these rashes harbor bacteria and are infectious). Other symptoms may include fever, sore throat, malaise, weight loss, hair loss, and headache. The latent stage of syphilis begins when all of the symptoms disappear and a latent infected person can continue to have syphilis for years without any symptoms. Without treatment, a third of infected people develop tertiary syphilis, which usually occurs 3-30 years after the initial infection.