The Facts
Syphilis is primarily a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. The disease has many clinical appearances that are often grouped into stages, depending on when they occur.
There are three stages of syphilis during which symptoms appear; however, not everyone will go through all three stages. Between these stages are symptom-free, or latent, periods.
Syphilis first appears as an acute infectious disease that then seems to go away on its own. It may reemerge a short while later, only to seem to go away again. It may also come back as a chronic, non-contagious medical condition.
This means there are two distinct groups of people with syphilis - those who are infectious but may recover spontaneously, and those who aren't infectious but won't get better without treatment. Blood tests for syphilis in either group of people will be positive.
Syphilis used to be a leading cause of death and disability. It is believed that it was introduced into Europe from the Americas by the early Spanish explorers. It spread throughout Europe and became a condition associated with sex, and since Venus was considered the "goddess of love," it became known as venereal disease (VD) ("venereal" means "of or relating to Venus"). There was no treatment for syphilis until the availability of antibiotics in 1945 when penicillin was developed. This medical condition is much rarer today due to the widespread use of antibiotics.
More than 46,000 cases of syphilis were reported in the United States in 2008. The rate of syphilis declined in the 1990s but has increased since 2000. In 2008, it was 7.6 cases per 100,000 for men and 1.5 cases per 100,000 for women.