Par Eric Charette | 08 June 2021


Syphilis is a bacterial STBBI on the rise among men who have sex with men since the 2000s. It is transmitted through contact with lesions (typically during sex). Luckily, the access to antibiotic treatment is free to all in Quebec.

ITSS Site4 Syphilis


Syphilis is a bacterial infection caused by the bacteria Treponema pallidum. The bacteria is transmitted through contact with a syphilis lesion. Generally, syphilis is spread during sex, but also during contact with a lesion (for example, skin-to-skin contact or wet kissing). Syphilis can also be transmitted from a pregnant mother to her baby, risking serious complications for the baby.

Who is at risk of infection?

Syphilis is less widespread than chlamydia or gonorrhea. Currently, a resurgence of syphilis is being observed in Québec, particularly affecting men who have sex with men, a group who are especially at risk.

The following activities are associated with a higher risk of infection:

  • vaginal, anal or oral-genital contact, with or without penetration
  • having sex with multiple partners
  • sharing sex toys
  • sharing injection materials

Symptoms and complications

Syphilis is sometimes nicknamed “the great imitator” because its clinical presentation can often be confused with other diseases. Classically, untreated syphilis evolves through three main clinical stages: primary, secondary and tertiary.

The most frequently observed symptoms, by stage:

  • Primary stage (appears between approximately 3 to 90 days after infection):
    • Painless sores or lesions (may disappear after several weeks)
  • Secondary stage (appears between approximately 2 to 12 weeks, sometimes several months, after the disappearance of lesions):
    • Skin rash (most often on the chest, stomach, hands, feet and genitals)
    • Flu-like symptoms (such as fever, headache, fatigue)
  • Tertiary stage (observed on average 5 to 30 years after the disappearance of lesions):
    • Cardiovascular complications, such as aortic aneurysm
    • Lesions that can damage many different parts of the body, including the skin and bones
    • Neurological complications, such as dizziness and dementia

In the long term, the consequences of syphilis are serious and can be life-threatening.

It is important to note that a syphilis infection can increase your risk of being infected by or transmitting HIV (if you are HIV positive).

Screening and treatment

How to test: Testing is performed using a blood sample.

When to test: The minimum delay before detection is approximately 10 days. The window period ends 12 weeks after exposure.

Treatment consists of antibiotics, which are administered by injection in the majority of cases. Often, one dose is enough, but a longer treatment period is sometimes necessary. Treatment is free for those affected, as well as their partners, as part of a program for free medication to treat sexually transmitted infections. Response to treatment is evaluated with the help of medical follow-up and additional blood tests.

It is also recommended to inform and treat all sexual partners from the last 90 days preceding the diagnosis. Screening is also recommended for recent sexual partners of up to one year prior to diagnosis.


There is no vaccine to protect against syphilis. The best means of protection is to use condoms, regardless of the type of sex. Since it is possible to be infected and not have any symptoms, routine screening is recommended for anyone who is single and sexually active, especially when there have been new partners or unprotected sex.

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