Syphilis is primarily a sexually transmitted infection (STI) caused by Treponema pallidum bacteria. The disease has many clinical appearances that are often grouped into stages, depending on when they occur.
There are 3 stages of syphilis during which symptoms appear; however, not everyone will go through all 3 stages. Between these stages are latent periods: periods that are symptom-free.
Syphilis first appears as an acute infectious disease that then appears to go away on its own. It may reemerge a short while later, only to appear 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 is an adjective formed from Venus). There was no treatment for syphilis until 1945, when penicillin was developed. This medical condition is much rarer today due to the widespread use of antibiotics.
As of 2009 (the latest statistics available), Canada has an infectious syphilis rate of 5 per 100,000 people. In Canada, the number of syphilis cases is increasing among both men and women, but moreso among males.