14 confirmed measles cases in Region of Waterloo

A child with a red measles rash (EyeEm Mobile GmbH/Getty Images)

Public health says there are now 14 confirmed cases of measles in the Region of Waterloo.

“We continue to see cases primarily in unimmunized individuals,” Dr. Rabia Bana, the region’s associate medical officer of health, said in Tuesday’s media release. “Given the highly contagious nature of measles, we expect this number to continue to rise.”

A previous update from public health on March 25 listed three confirmed cases in the region.

Public health has identified several areas of potential measles exposure on its website. The latest is Grand River Hospital’s emergency room on March 29 between 4 p.m. and 7 p.m.

Anyone who was at any of the possible exposure locations during the dates and times specified is asked to contact Region of Waterloo Public Health, especially if they experience any of the following symptoms: fever, cough, runny nose, white spots in the mouth and red watery eyes that are sensitive to light. The main symptom of measles is a red rash that usually appears a few days after other ailments. These usually occur 21 days after exposure to the virus but can also show up as early as seven to 12 days.

Measles update

Public Health Ontario said 557 measles cases have been reported across the province in the first three months of 2025.

Most of those illnesses, approximately 60 per cent, were within the area covered by Southwestern Public Health and Grand Erie Public Health.

On Friday, the province’s chief medical officer of health expressed his optimism that the outbreak was showing signs of slowing.

“We’re seeing stable numbers week after week, which gives us hope,” Dr. Kieran Moore said. “This virus typically spreads in late winter and through spring, and we’re finding that it’s not accelerating. So that’s probably thanks to the great work in communities to try to limit spread, as well as our messaging with local public health agencies to affected communities and health system preparedness.”

The origin of the outbreak has been traced to a large Mennonite gathering in New Brunswick last fall and, as Moore explained in a memo to Ontario’s medical officers of health earlier this month, there is a disproportionate number of cases within the Mennonite, Amish and Anabaptist communities due to under-immunization.

- With files from The Canadian Press