Infectious Syphilis Cases Increasing Locally

Advisory Alert

May 14, 2019

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Re: Infectious Syphilis Cases Increasing Locally

I am writing to advise you of a recent increase in confirmed cases of infectious syphilis within the Public Health Sudbury & Districts’ catchment area. This advisory alert will provide you with information regarding the local epidemiology of syphilis, its risk factors, clinical management considerations, and reporting requirements. Please be vigilant for syphilis in your patients presenting with clinically compatible signs, symptoms and risk factors for infection.

Local Epidemiology

The number of cases of infectious syphilis has been increasing locally over the last several years. Since 2014, a total of 40 cases have been confirmed with 13 having been reported since the beginning 2019. Most cases reported this year involve men who have sex with men.

Etiology, Transmission, Signs and Symptoms

Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. Clinical manifestations vary by stage (primary, secondary, latent, tertiary). Primary, secondary and early-latent syphilis are considered infectious (see Table 1, below) and are the focus of this alert. The main mode of transmission is by vaginal, anal and oral sexual contact. Vertical transmission can occur, resulting in congenital syphilis. Direct contact with lesions of primary and secondary syphilis pose the greatest risk of transmission. Not all lesions may be readily apparent. A high proportion of individuals fail to recall primary chancre. Signs and symptoms may be modified in the presence of HIV co-infection.

Table 1: Clinical Manifestations of Infectious Syphilis by Stage of Infection

StageClinical ManifestationsIncubation Period
PrimaryChancre, regional lymphadenopathy3 weeks (3-90 days)
SecondaryRash, fever, malaise, lymphadenopathy, mucous lesions, condyloma lata, patchy or diffuse alopecia, meningitis, headaches, uveitis, retinitis2-12 weeks (2 weeks to 6 months)
Early LatentAsymptomatic˂1 year

Diagnosis: Risk Factors

Serologic testing for syphilis is recommended for patients who have signs or symptoms compatible with syphilis and also in the following individuals:

Diagnosis: Laboratory Testing

  1. Testing from lesions of primary and secondary syphilis: use direct fluorescence for detection of T. pallidum. Submit serous exudates from suspected lesions or chancres obtained in accordance with the instructions in the Direct Fluorescence Kit. The slide is to be labelled with the patient’s full name and date of birth. Use the General Test Requisition from Public Health Ontario Laboratory available at:
  2. Serology: indicated for routine diagnosis of suspected syphilis cases, monitoring of treatment of diagnosed syphilis, and as part of prenatal screening, and donor screening. Submit serum for analysis along with a completed General Test Requisition as above.

Further information on the syphilis serologic screening test and algorithm and test interpretation is available from Public Health Ontario at:


The following table outlines the preferred treatment for infectious syphilis:

PatientPreferred treatment
All non-pregnant adults with primary, secondary or early latent syphilisBenzathine penicillin G 2.4 million units IM as a single dose
Epidemiological treatment* of all sexual contacts in the preceding 90 days to primary, secondary or early latent syphilis
Pregnant women with primary, secondary or early latent syphilisBenzathine penicillin G 2.4 million units IM weekly for 1–2 doses
*Refers to treatment provided when diagnosis is considered likely on clinical, laboratory or epidemiologic grounds, but before results of confirmatory tests are known

Please consult the Canadian Guidelines on Sexually Transmitted Infections for additional guidance at:

Health care practitioners can have access to publicly funded syphilis treatment for their patients by contacting the Sexual Health Clinic using the contact information below.


Report all confirmed and suspected cases of syphilis to Public Health Sudbury & Districts at 705.522.9200, ext. 482.


Ariella Zbar, MD, CCFP, MPH, MBA, FRCPC
Associate Medical Officer of Health and Director, Clinical Services

This item was last modified on May 14, 2019