For the third time in 2019, public health officials in Montreal are warning doctors and nurses to be on the lookout for a disease that was eradicated in Canada two decades ago.

On Friday the agency said that a person infected with measles had been in frequent contact with an unvaccinated child at a school in Montreal's Ahuntsic neighbourhood.

There are no indications the child contracted measles, but health professionals vaccinated a dozen staff and students at the elementary school on Friday, and booster shots against the potentially deadly and life-altering disease were offered over the weekend at a neighbourhood CLSC.

“One of those contacts identified was not vaccinated and was going to school so there was a preventive intervention done in that school,” said Renee Pare of Montreal Public Health.

As a precautionary measure that child has been ordered to stay home until the incubation period for measles has ended.

According to the notice the unvaccinated woman was exposed to measles during a recent trip to France and was contagious from April 26 to May 4.

During that time the infected person flew from Paris to Montreal, then visited clinics on April 28 and 30, and she also went to a hospital on May 1.

That means it's possible someone else who has not been immunized could show up at hospitals or clinics up to May 25.


Prior cases in Quebec

Measles had been eradicated in Canada in 1998 but has since begun to return to the country, almost always because of international travellers who are not vaccinated.

Dr. Marie-Astrid Lefebvre, Infectious Disease Unit, Montreal Children's Hospital said cases in Canada are on the rise.

"In Canada we see mostly imported cases that come from abroad," said Dr. Lefebvre, and that as confirmed was in two of the three cases in Montreal this year.

In January a woman who had travelled to Russia contracted the disease, and officials warned people in Frankfurt, Toronto, and Montreal of possible exposure.

In March an employee at the MUHC Glen site contracted measles and was at work while contagious for several days.

"We're seeing dozens of cases across the country since the beginning of the year," said Dr. Lefebvre.

To date there have been 43 cases in Quebec, British Columbia, Ontario, Alberta and the Northwest Territories, and 86.7 percent of those infected were never vaccinated.

About 20 cases of measles were reported last year in Canada.

In the U.S., there are currently over 750 confirmed cases. Almost all are in New York, coming after one unvaccinated child travelled to Israel and came home with the disease.

"These unimmunized populations can really serve as a hotspot for measles so as soon as there's one case- the disease is so contagious that it very rapidly spreads," said Lefebvre.

More than 1,200 people have died in Madagascar, where more than 115,000 people were infected in March and April.

The measles vaccine is very safe but because of a fraudulent British report from in the 1990s that faked data, vaccination rates have dropped throughout the world.

Measles vaccinations are done in two doses for infants: one at 12 months, the other at 18 months.

To make it easier for children to get vaccinated in a timely fashion, Quebec is altering the vaccination schedule as of June to get shots for the measles, mumps, rubella, hepatitis b and whooping cough.


Highly contagious and dangerous

Measles is one of the most easily spread diseases, with non-immunized people at an 80 percent chance of contracting the disease if they are in the same room as a contagious individual.

"Just being in the same room as a person is enough to be exposed," said Pare.

It normally takes seven to 14 days to begin showing symptoms; those symptoms include a rash, fever, cough, fatigue, nasal discharge, and white spots in a person's mouth.

It can cause permanent hearing loss, blindness, and the disease kills about one in a thousand.

A person is contagious for four days before a rash appears, and for four days after the rash disappears.