Public Health Update for Clinicians: Confirmed measles case in Windsor-Essex

Alert Date
Location
Windsor-Essex County

The Windsor-Essex County Health Unit (WECHU) recently received a laboratory-confirmed measles case and issued a public warning to anyone who may have been exposed to measles infection at various locations on multiple dates. See Updated Media Statement: Windsor-Essex County Health Unit Issues Warning for Possible Measles Exposure.

The Windsor-Essex County Health Unit (WECHU) would like to highlight that Ontario continues to experience a multi-jurisdictional measles outbreak1. In the past, measles has been rare in Ontario, with most cases associated with international travel. However, there has been an increase in measles world-wide and in Canada, with 91% of measles cases reported in 2025 resulting from exposures within Canada.2 As of February 26, 2025, 177 measles cases (127 confirmed, 50 probably) are associated with this multi-jurisdictional outbreak.1 All outbreak cases were in individuals born in or after 1970. Of those cases that were children and adolescents, 97.9% were unimmunized.1 

Health Care Provider Recommendations

Given the current prevalence of measles in Windsor-Essex County, the WECHU encourages health care providers to take the following actions: 

  1. For contacts of confirmed cases: Ensure any patient’s identified as having been exposed to a suspected or confirmed case of measles are instructed to contact the WECHU to be assessed for eligibility for post-exposure prophylaxis
  2. Consider Measles as a Differential Diagnosis: Clinicians are strongly encouraged to consider measles as part of the differential diagnosis when clients present with:
    • febrile illness and rash
    • history suggesting that they are not immune to measles
    • history of travel to areas with measles outbreak or are known to have had an epidemiologic link to a measles case or outbreak
  3. Verify infection prevention and control measures are in place at your facility
  4. Ensure appropriate testing for Measles: It is essential to complete ALL of the following tests to confirm diagnosis:
    • Nasopharyngeal swab/aspirate or throat swab for PCR
    • Blood specimen for serology
    • Clean catch urine for PCR
  5. Report: Timely reporting of suspected or confirmed cases of communicable diseases is essential for their control.
    • Duty to Report: Clinicians are required to report all diseases of public health significance (DOPHS), including all suspected and confirmed measles cases and cases awaiting lab results. measles as per the requirements in accordance with Ontario Reg 135/18 and amendments under the Health Protection and Promotion Act, R.S.O. 1990. Refer to the DOPHS List for all reporting requirements.  
    • Reporting forms are available on the WECHU website. Reporting forms should be filled out completely and faxed to 226-783-2132.

For questions or concerns, please call 519-258-2146 ext. 1420 during regular office hours, and 519-973-4510 during after-hours and weekends. You can also visit our website. 

For more information, visit:

  1. Public Health Ontario, 2025: Enhanced Epidemiologic Summary. Measles in Ontario
  2. Government of Canada, 2025: Measles and Rubella Weekly Monitoring Report. Week 7 (February 9 to February 15, 2025)
  3. Measles: For Health Professionals
  4. Ministry of Health, 2024: Appendix 1: Case Definitions and Disease Specific Information: Measles
  5. Public Health Ontario, 2025: Measles Information for Clinicians
  6. Government of Canada, 2025, Measles vaccines: Canadian Immunization Guide