Syphilis as a Public Health Topic

Syphilis is a bacterial sexually transmitted infection caused by Treponema pallidum. It has been documented in medicine for centuries and was long among the most feared infections before antibiotics became available. Today it is curable in most cases, yet it remains a regular subject of public health reporting in Canada and elsewhere.

This article covers the general medical background, which applies to anyone who is sexually active.

How it is transmitted

Syphilis spreads mainly through direct contact with a sore during vaginal, anal or oral sex. It can also pass from a pregnant person to a fetus, which is called congenital syphilis. Condoms reduce but do not fully eliminate the risk, because sores can occur on skin that a condom does not cover.

Stages of infection

Clinicians describe the illness in stages.

• Primary: a firm, usually painless sore appears at the site of infection, often weeks after exposure
• Secondary: a rash, frequently on the palms and soles, sometimes with fever, swollen glands or patchy hair loss
• Latent: no visible symptoms, although the infection remains in the body
• Tertiary: serious damage to the heart, brain or other organs, seen after years without treatment

Because the sores and rash can be mild or go unnoticed, many people are unaware of an infection for some time.

Diagnosis and treatment

Diagnosis normally relies on blood tests, sometimes combined with examination of a sore. Treatment typically involves the antibiotic penicillin, with the dose and duration depending on the stage. Follow-up blood tests are used to confirm that the infection has cleared. Partners of an infected person are generally notified through confidential public health processes.

Surveillance in Canada

Syphilis is a nationally notifiable disease in Canada. Provincial and territorial health authorities collect case reports, and the Public Health Agency of Canada compiles national summaries. Health officials have, over several periods, described increases in reported infectious syphilis in various regions, and these shifts are tracked through the same reporting system.

Testing programs and the window period

Screening for sexually transmitted infections takes place in many settings, and the scope and rules of testing programs differ from place to place. Such programs usually screen for several infections, and public discussion often notes that a test captures only a point in time, since infections have a window period before they can be detected.