Syphilis is a chronic, degenerative, sexually transmitted disease caused by the bacterium Treponema pallidum. Although modern treatments now control the disease, its incidence remains high worldwide, making it a global public health concern. Spread by sexual contact, syphilis begins as a small, hard, painless swelling, called a primary (or Hunter's) chancre. The disease is very contagious in the early stages. The initial sore will usually pass away in about eight weeks, but the disease will then spread through the body and lodge in the lymph nodes, causing a skin rash to appear in two to four months along with fever and headaches. This second stage can last two to six weeks. After a latent period, which can extend for years, the disease can appear in various bodily organs and it can be spread to others.

The earliest records of syphilis are those of Spanish physician Rodrigo Ruiz de...