Toronto Public Health said it was investigating a confirmed case of measles linked to international travel, and warned that members of the public may have been exposed to the virus at a location in the west end of the city.
The agency said potential exposure had occurred at a business on Roncesvalles Avenue on Thursday, May 7, and advised anyone who had been there to monitor for symptoms.
Measles is among the most contagious viral infections. It can spread through the air and linger in an enclosed space for up to two hours after an infected person has left, making contact tracing for public exposures difficult.
Symptoms typically appear between one and three weeks after exposure and include fever, cough, a runny nose and a characteristic rash. Health officials said people who are not immune should be especially alert in the weeks following a potential exposure.
Toronto Public Health urged residents to confirm that they and their children are up to date with measles vaccination, which it described as the most effective protection. The case adds to a rise in travel-related measles infections reported across Canada in recent months.