Disease Debrief: Syphilis

Updated on November 19, 2018

NCCID Disease Debriefs provide Canadian public health practitioners and clinicians with up-to-date reviews of essential information on prominent infectious diseases for Canadian public health practice. While not a formal literature review, information is gathered from key sources including the Public Health Agency of Canada (PHAC), the USA Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO) and peer reviewed literature.

Questions, comments and suggestions regarding this debrief are most welcome and can be sent to Sheikh.Qadar@umanitoba.ca.

What are important characteristics of Syphilis?


Syphilis is a sexually-transmitted bacterial disease caused by Treponema pallidum subsp. pallidum. T. pallidum subsp. Pallidum causes venereal syphilis; T. pallidum subsp. endemicum causes endemic syphilis (bejel); T. pallidum subsp. pertenue causes yaws and T. carateum causes pinta.

It is the third most commonly reported sexually transmitted infection (STI) after Chlamydia and Gonorrhea in Canada. The infection can cause serious health consequences and moves through three stages (primary, secondary and latent stages) if left untreated.

Signs and Symptoms:

Detailed descriptions of clinical manifestations in different stages and the incubation time associated with each.

Stage Clinical signs & symptoms Incubation period
Primary Chancre (usually occurs where syphilis entered the body and at times difficult-to-notice area such as the vagina or anus), regional lymphadenopathy 3-6 weeks
Secondary Rash, fever, malaise, lymphadenopathy, mucus lesions, condyloma lata, patchy or diffuse alopecia, meningitis, headaches, uveitis, retinitis 2-12 weeks

(2 weeks–6 months)

Latent Asymptomatic Early: less than year

Late: at or after 1 year

Tertiary Syphilis

Stage Clinical signs & symptoms Incubation period
Cardiovascular Syphilis Aortic aneurysm, aortic regurgitation, coronary artery ostial stenosis 10-30 years
Neurosyphilis Headaches, vertigo, personality changes, dementia, ataxia, presence of Argyll Robertson pupil < 2 years–20 years
Ocular syphilis Vision changes, decreased visual acuity leading to permanent blindness
Gumma Tissue destruction of any organ; manifestations depend on site involved 1-46 years (most cases 15 years)


Stage Clinical signs & symptoms Incubation period
Early Fulminant disseminated infection, mucocutaneous lesions, osteochondritis, anemia, hepatosplenomegaly, neurosyphilis Onset < 2 years
Late Interstitial keratitis, lymphadenopathy, hepatosplenomegaly, bone involvement, anemia, Hutchinson’s teeth, neurosyphilis Persistence > 2 years after birth


Over the years, rates of syphilis in Canada have surged. According to the Canada Communicable Disease Surveillance report of 2010-2015, the rate of syphilis has increased by 85.6% from 2010 to 2015 (5.0 to 9.3 cases per 100,000 population). In females, the rate has increased from 0.9 per 100,000 population in 2010 to 1.2 per 100,000 population in 2015 whereas in males the rate has surged from 9.2 (2010) to 17.5 per 100,000 population (2015). However, these national rates do not include recent provincial/territorial outbreaks in Canada.

Laboratory Diagnosis:

Generally, two types of blood test are performed for laboratory confirmation of syphilis: non-treponemal tests (NTT) such as rapid plasma regain (RPR); followed by confirmatory treponemal tests if the NTT is reactive.

Dark-field microscopy, Direct/Indirect Fluorescent Antibody (DFA/IFA) or Nucleic Acid Amplification Tests [NAAT, e.g., Polymerase Chain Reaction (PCR) are options for testing lesions of primary and secondary syphilis]. DFA/IFA tests are not reliable for oral/rectal lesions because of cross-reaction with non-pathogenic treponemes in oral and anal specimen. An optional for such specimen is NAAT (PCR), if NAAT not available and initial serological testing is negative, repeat serology in 2-4 weeks.

Treponemal enzyme immunoassays (EIA) may provide a more sensitive screening test for syphilis. Treponemal tests include the T. pallidum particle agglutination (TP-PA), microhemagglutination-T. pallidum (MHA-TP), fluorescent treponemal antibody absorbed (FTA-ABS), EIA to detect IgG and/or IgM antibodies and the syphilis Inno-Lia. Treponemal antibodies appear earlier than nontreponemal antibodies and usually remain detectable for life, even after successful treatment. In cases where a treponemal test is positive, then a nontreponemal test with titer should be performed to confirm diagnosis and treatment.


All women in their first prenatal visit should be screened. Blood testing should be performed on patients living in high prevalence communities and populations and patients at risk during the third trimester (28-32 weeks) and at delivery.

Infants born through mothers who have reactive nontreponemal and treponemal tests should be evaluated for congenital syphilis.


The basic transmission mechanism is through either vaginal, anal and/or oral sex. Very rarely, syphilis is transmitted through kissing (oral contact), needle sharing, blood transfusion, accidental inoculation and organ transplantation.

In the case of transmission from women to infants, most of the congenital syphilis cases are infected in utero but can also be contacted with an active genital lesion at the time of delivery.

Risk of Mother-to-Child Transmission:

The risk of transmission in untreated women is very high (70-100%) with primary or secondary syphilis, 40% with early latent syphilis and 10% in late latent stages in pregnancy. Close to 40% of pregnancies in women with syphilis infections result in fetal deaths.


In sexually active persons, the risk of syphilis should be clearly elucidated by health care professionals to avoid ambiguity, especially regarding transmission through oral sex and the use of protection. Patients should be provided information on the use of barrier methods. Patients with syphilis infections and their partners should abstain from unprotected intercourse until treatment of both partners is complete and an adequate serological response is determined.

According to the CDC, partner-based interventions including partner notification play a vital role in prevention of syphilis infections.

To prevent congenital syphilis, routine prenatal screening for syphilis is recommended.


Below are the treatment protocol according to the stages, with alternative therapies listed as well.

Stage Treatment Alternative treatment for Penicillin-allergic patients
Non-pregnant adults with primary, secondary & early latent


Benzathine penicillin G

2.4 million units IM as a single dose

Doxycycline 100 mg PO bid for 14 days

To be use in exceptional situations:

Ceftriaxone 1g IV or IM daily for 10 days

Latent syphilis, latent syphilis of unknown duration, cardiovascular syphilis & other tertiary syphilis excluding CNS Benzathine penicillin G 2.4 million units IM weekly for 3 doses Doxycycline 100 mg PO bid for 28 days

Ceftriaxone 1g IV or IM daily for 10 days

Neurosyphilis Penicillin G 3-4 million units IV q 4h (16-24 million units/day) for 10-14 days Ceftriaxone 2g IV or IM daily for 10-14 days

Pregnant women

Primary, Secondary, Early latent (<1 yr. duration) Benzathine penicillin G 2.4 million units IM weekly for 1-2 doses No suitable alternative available
Late latent syphilis, latent syphilis of unknown duration, cardiovascular syphilis and other tertiary syphilis excluding CNS Benzathine penicillin G 2.4 million units IM weekly for 3 doses No suitable alternative available
Congenital syphilis Crystalline penicillin G 50,000 units/kg IV every 12 hrs. for the first week of life and every 8 hrs. for 10 days


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What is happening with current outbreaks of Syphilis infections?


There has been a steady increase in syphilis cases during the last five years. In the first nine months of 2018, about 733 cases have been reported, which surpasses the 536 cases of 2017 (male 414 and female 122) and 422 from the year 2016 (male 370, female 52).

British Columbia:

Since 2010, syphilis cases have been increasing in British Columbia. In the province, about 546 cases were reported in 2014 (male 521, female 24), 757 in 2015 (male 721, female 28), about 755 cases were reported in 2016 (male 721, female 33) and about 685 cases of syphilis were reported in 2017 respectively.


According to the Saskatchewan Health Authority, the cases of infectious syphilis have been sharply increasing as well. In 2015, about 24 were reported whereas in 2016 the number of cases jumped to 85 and about 120 cases were reported in 2017. In the first eight months of 2018, about 72 cases have been reported so far.


In the year 2015, 205 cases of syphilis was reported whereas in 2017 the case counts were more than 400% compared to 2013.

Women: In 2015, Manitoba Health reported that syphilis rates among women are ten times higher in 2015 than in 2012. About 86% of these female cases were among women of childbearing age (15-39) which increases risk for congenital syphilis. About four of every ten new infections were in women in 2017.

According to Winnipeg Regional Health Authority (WRHA), just in the first six months of 2018 there have been more than 120 cases (gender specific breakdown not available).


In Nunavut there were about 82 cases of syphilis reported in 2014, giving an incidence rate of 227.6 per 100,000 population and 56 cases (153.3 per 100,000) were reported in 2015.


In Ontario, about 1052 and 1175 syphilis cases were reported in 2015 and 2016 respectively. During the first six months of 2018, 981 cases were reported.

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What is the current risk for Canadians from Syphilis disease?

The rates of syphilis in Nunavut, British Columbia and Manitoba have increased above the national average.

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What measures should be taken for a suspected Syphilis infection case or contact?

Case and Contact Management:

The government of Canada has developed national notification requirements for laboratory confirmed cases of infectious syphilis and early congenital syphilis.

These case definitions are strictly for the purpose of case identification and reporting.

Identifying & Reporting:

Syphilis infection is a nationally and provincially notifiable and reportable infection to the Public Health Agency of Canada.

Non-infectious syphilis (late, latent, cardiovascular and neurosyphilis) may be reportable at the provincial /territorial level but is not notifiable to the Public Health Agency of Canada.

Infection Control & Prevention:

The Government of Canada provides guidelines for syphilis infection control and prevention.

Circumventing unprotected sexual activities which can cause reinfection until both partners have completed antibiotic treatment, syphilis testing for sexually active individuals, correct use of condoms, safe sex and needle-sharing practices.

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