Montreal Public Health says 14 cases of measles have led to thousands of contacts

The measles virus is highly contagious and can remain active for hours in the air. (Alissa Eckert/CDC - image credit)
The measles virus is highly contagious and can remain active for hours in the air. (Alissa Eckert/CDC - image credit)

Montreal Public Health says there have been 14 confirmed cases of measles in the city since the beginning of February, with only two believed to have been acquired abroad, suggesting local transmission.

These cases have exposed several thousand individuals in various settings in Montreal, including various health-care environments, the health agency said in an update Wednesday.

A complete list of locations where exposure may have occurred has been published online. The list includes pharmacies, supermarkets, restaurants, coffee shops, Metro lines, daycare centres, pediatric ERs and hospitals.

Given the current resurgence of measles worldwide, Montreal Public Health says it anticipates infections among individuals who have travelled abroad, especially if they were not adequately protected against the virus.

Travel associated with March break could lead to an increase in infections acquired abroad, the agency says.

The agency is urging health-care professionals to verify their own vaccination status and get vaccinated immediately if necessary to avoid preventive isolation if exposed to a contagious case.

"We recommend checking the protection status of all personnel working in health-care settings," the statement said.

Health-care professionals are asked to report any suspected measles cases by phone without waiting for laboratory results in order to expedite public-health interventions, such as contact tracing.

Fast reporting will also facilitate the administration of prophylaxis to individuals at risk of complications within the expected short timeframes, the statement said.

This week, Montreal Public Health is launching a measles vaccination campaign in select schools.

Neither students nor school staff are required to be vaccinated in Quebec, but those who are unvaccinated could be forced to stay home for weeks at a time if infection is detected in the school, according to Dr. Paul Le Guerrier, who is responsible for immunization at Montreal's health agency.

He said both adults and children will be excluded from schools up to 14 days after the last case of measles in the school.

"If there are several cases in the school, this could be a month or a month-and-a-half being excluded from the school," he said.

Dr. Marie-Astrid Lefebvre, a pediatric infectious diseases specialist with the Montreal Children's Hospital, told CBC News that measles, which travels in air, is "very easy to transmit to multiple people who are just present in the same area as the individual."

Across the world, measles remains among the common causes of child deaths.

"Measles has been eliminated from Canada, but from time to time there are travellers who are not adequately vaccinated that go to many countries in the world where measles is endemic," said Le Guerrier.

It can take one to two weeks before someone exposed to the virus begins showing symptoms. Those symptoms include: high fever, runny nose, coughing, red eyes and general discomfort. Then, a rash develops on the face and body.

According to Quebec Public Health, a person with the virus is contagious four days before the rash appears and can remain contagious for up to four days afterward.

Complications include ear infections, pneumonia, convulsions and, in some cases, death.