Transmission occurs primarily during the infectious phase which consists of primary, secondary, and early latent syphilis. Primary syphilis is characterized by a painless ulcer approximately 3 weeks after exposure. Secondary syphilis is characterized by a generalized eruption 4 to 6 weeks after the primary stage in untreated patients. After weeks or several months, secondary manifestations resolve and about one-third of untreated cases become clinically latent sometimes leading to late manifestations involving the cardiovascular system, the central nervous system, skin, bones, and viscera. A diagnosis of early latent syphilis is made when the clinical situation and nontreponemal antibody titres reflect recent infection for which aggressive follow-up is necessary.
Perinatal transmission can occur, especially during the infectious phase.
Since July of 1997, British Columbia has experienced a serious outbreak of infectious syphilis. A total of 273 cases have been reported in the 30 months since the outbreak began. Age-adjusted rates are highest in men 30 to 49 years of age and women 20 to 39 years of age. With this latter group, condoms are not often used. There were two cases of congenital syphilis in British Columbia in 1997.