Infectious Syphilis Cases Rise in Females of Childbearing Age
Hamilton Public Health Services is notifying healthcare providers of a significant increase in the rate of infectious syphilis among females of childbearing age. While syphilis continues to disproportionately impact men who have sex with men (MSM), local data suggests the rate of infectious syphilis among females has increased 4 times from 2019 to 2022. In 2022, there were 33 confirmed female cases in Hamilton, representing 11 per 100,000 population.
Additionally,74% of the female infectious syphilis cases were among those of child-bearing age. This resulted in a rise in the number of infants undergoing investigation for congenital syphilis, due to potential transmission during pregnancy. Between 2018 to 2022, a total of 7 confirmed cases of congenital syphilis were identified, highlighting a need to ensure testing during the prenatal period.
Recommended Actions
A pregnant individual infected with syphilis may have no symptoms. If present, symptoms can include chancres on the genitals or mouth, a rash, fever and swollen glands.
The Public Health Agency of Canada (PHAC) recommends the following screening during pregnancy:
- Universal screening during the first trimester or at first pre-natal visit
- Repeat screening at 28-32 weeks and again at time of delivery:
- in areas with outbreaks of syphilis or
- for pregnant individuals at ongoing risk of infection or reinfection - Consider more frequent screening for those at high risk of infection
- Screen all people who deliver a stillborn infant after 20 weeks gestation
- Individuals at high risk of acquiring syphilis (underhoused, sex workers) may be less likely to receive standard prenatal care, for this reason, screening pregnant individuals in the ER is recommended.
- Ensure partners of pregnant individuals with syphilis are screened and treated to reduce risk of re-infection.
- Promote the need for safer sex practices, including reducing the number of sexual partners during pregnancy.
Transmission
Congenital syphilis is caused by the bacterium Treponema pallidum. It is most commonly transmitted from pregnant individuals with syphilis to baby during pregnancy. However, transmission can occur at the time of delivery through contact with active genital lesions during vaginal birth.
The risk of transmission to the fetus is influenced by the stage of maternal infection as well as gestation age at the time of diagnosis and treatment. The likelihood of vertical transmission to the fetus is 70-100% in untreated cases of primary syphilis or secondary syphilis and 40% during the early latent phase.
If untreated, maternal syphilis can result in adverse pregnancy outcomes including miscarriage, pre-term birth, low birth weight, neonatal death, and/or congenital syphilis.
Diagnostic Testing and Treatment
Treatment of pregnant individuals during early pregnancy can drastically reduce the risk of congenital syphilis. Fetal infection can be prevented with adequate treatment before 16 weeks gestation. Adequate maternal treatment is a penicillin-based regimen initiated at least 1 month prior to delivery. Medication can be ordered by www.hamilton.ca/hcp-sti.
Pregnant individuals diagnosed with infectious syphilis and suspect congenital syphilis cases should be managed in consultation with an infectious disease specialist. It is important to ensure that referral does not delay treatment.
Advise all individuals who are treated to abstain from condomless sexual contact until treatment has been completed and ideally for seven days after completion of treatment.
Reporting Requirements
Syphilis is reportable to the Medical Officer of Health under the Health Protection and Promotion Act, R.S.O. 1990, c.H.7.
Reporting to Hamilton Public Health Services
To report suspect and confirmed cases of syphilis, call PHS Monday to Friday 8:30 am to 4:30 pm at 905-528-5894 or Fax 905-546-2203.