Concerning Rise in Syphilis Cases in Canada

Often associated with history books or period novels, syphilis is far from being a relic of the past. In Canada, it remains very present, and has seen a sharp increase in recent years. According to data from the Public Health Agency of Canada, the number of infectious syphilis cases nearly doubled between 2018 and 2023, rising from 6,371 to 12,135 cases.

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Often associated with history books or period novels, syphilis is far from being a relic of the past. In Canada, it remains very present, and has seen a sharp increase in recent years. According to data from the Public Health Agency of Canada, the number of infectious syphilis cases nearly doubled between 2018 and 2023, rising from 6 371 à 12 135 cases.¹.

Understanding syphilis and its symptoms is an important step toward protecting your sexual health and reducing the risk of STIs.

What Exactly Is Syphilis?

Syphilis is a sexually and blood-transmissible infection (STI) caused by a bacterium called Treponema pallidum.

Nicknamed “the great imitator,” syphilis lives up to its name: its symptoms can resemble those of many other infections or even go completely unnoticed, making diagnosis challenging. Knowing how it manifests is essential for early detection and protecting your sexual health.

How Is It Transmitted?

Infectious syphilis is mainly transmitted through direct contact with a chancre, a sore or ulcer on the skin or mucous membrane. This usually occurs during sexual activity, including:

Vaginal or frontal sex;
Anal sex;
Oral sex (including oral-anal contact or anulingus).

It can also spread through sharing sex toys or drug injection equipment, though these routes are less common.

Even without visible symptoms, an infected person can still transmit the disease.

Syphilis can also pass from a pregnant person to their baby during pregnancy, causing congenital syphilis—a serious condition that can lead to severe complications for the child.

Symptoms of Syphilis

Syphilis often goes unnoticed, especially early on, as many people show no visible signs. Without treatment, the infection remains in the body and can progress. Regular testing is essential for early detection.

Untreated syphilis typically progresses through stages, each with common symptoms².

Primary stage: About 3 weeks after infection, a small painless sore (chancre) appears on the genitals, anus, mouth, or throat. It may go unnoticed and heal on its own. Nearby lymph nodes may swell.
Secondary stage: Entre 2 et 12 semaines après l’infection, une éruption cutanée peut survenir, le plus souvent sur la poitrine, le ventre, les mains, les pieds et les organes génitaux. Des symptômes généraux peuvent également apparaître, tels que de la fièvre, des maux de tête, de la fatigue, des douleurs musculaires, une perte d’appétit ou l’apparition d’autres plaies.
Latent stage: At this stage, there can be no symptoms for years or decades.
- Early latent stage: Early latent syphilis is when it's been less than 12 months since the start of infection. Even if there are no symptoms, it can still be passed on to others.
- Late latent stage: Late latent syphilis is when it's been over 12 months since the start of infection. The risks of transmission are lower.³.
Tertiary syphilis: Between 5 and 40 years after the initial infection, syphilis can affect several systems in the body, including the cardiovascular system. It can cause lesions called syphilitic gums as well as serious, sometimes fatal, diseases. Fortunately, the majority of cases do not progress to this stage.
Neurosyphilis : At any stage, syphilis can affect the brain or nervous system. It can lead to serious complications, such as hearing or vision loss, cognitive impairment, paralysis, meningitis, and vertigo.

It's important to note that syphilis infection can increase the risk of becoming infected and transmitting HIV.

Syphilis Cases Are Increasing: What the Latest Data Shows

In Canada, syphilis is experiencing a significant increase. According to a report from the Public Health Agency of Canada⁴, the number of infectious syphilis cases nearly doubled between 2018 and 2023, highlighting the importance of screening and prevention.

Key Facts: Canada, 2023

Men still account for the majority of reported cases, representing 64% of infections
Among men, those aged 30 to 39 have the highest incidence rate
Since 2018, the incidence rate among women has tripled.
Among women, those aged 20 to 29 are most affected, making up 40% of female cases.
The increase in cases is much faster in the non-GBMSM population (gay, bisexual, and other men who have sex with men), with a 177% rise compared to 2% in the GBMSM population

Alarming Increase in Québec City

The rise in syphilis cases isn’t limited to the national level: Québec City is feeling the impact particularly strongly.

According to the Public Health Directorate of the CIUSSS de la Capitale-Nationale, the incidence rate in 2025 has reached 21.4 cases per 100,000 residents, placing the region third in the province and well above the Québec average of 13.0 cases per 100,000.⁵.

The CIUSSS Public Health Directorate warns: 2025 could set a new record for reported cases.

Why Syphilis Is Making a Comeback: Prevention Challenges

Several factors explain why syphilis is sharply increasing in Canada:

Insufficient Testing : Some infected individuals don’t get tested, especially if they have no visible symptoms (remember, syphilis can remain silent for a long time!).
Limited Awareness: Gaps in sex education and STI prevention make it harder for people to recognize risks and take protective measures.
Access to Care: Regional and socio-economic inequalities limit access to healthcare services, particularly among marginalized populations.
Reinfection: Even after treatment, it’s entirely possible to contract syphilis again if exposed.

Syphilis Screening: What You Need to Know

Like most STIs, syphilis can go unnoticed. That’s why regular testing is recommended, even when you feel fine and have no symptoms.

At Prelib, syphilis testing is done through a simple blood test.

It’s important to consider the window period when testing for STIs, AKA the time after exposure during which an infection may be present but not yet detectable. A follow-up test at the end of the window period is recommended to confirm previous results. For syphilis, this period can last up to 12 weeks.

If you develop symptoms (such as a sore or chancre), an in-person consultation is advised, as a physical examination is essential for proper care.

How Syphilis Is Treated

Syphilis is treated with antibiotics, most often in injectable form. In most cases, a single injection is enough, but some situations may require a longer course of treatment. Regular clinical and serological follow-up is essential to monitor the response to treatment and correctly interpret subsequent test results.

Le traitement est offert gratuitement à la personne infectée et à ses partenaires, dans le cadre du Programme de gratuité des médicaments pour le traitement des infections transmissibles sexuellement.

Protecting Yourself From Syphilis Reinfection

Even after completing treatment, it’s possible to contract syphilis again if you’re exposed to the infection.

To reduce the risk of reinfection and transmission, it’s important to notify any sexual partners who may have been exposed. The look-back period for partner notification depends on the stage of the infection. This table outlines the recommended time frame for each stage to identify partners who should be informed.

Syphilis Prevention Strategies

In today’s context, prevention plays a crucial role in slowing the rise of syphilis cases. The most effective protection remains condom use, regardless of the type of sexual activity. Since it’s possible to be infected without knowing, routine testing is recommended for all sexually active single individuals—especially when new partners are involved or in cases of unprotected sex.

In addition to these measures, there is an extra prevention tool for certain at-risk individuals: doxy-PPE (Doxycycline Post-Exposure Prophylaxis). When taken within 72 hours after a high-risk exposure, doxy-PPE can reduce syphilis transmission by up to 70%⁶.