Hamilton health workers prepare as measles appear in Niagara, Toronto

Hamilton health care workers are taking precautions should a measles case appear locally after five cases of measles in Toronto and one in Niagara have appeared in recent weeks. Because they don't have obvious connections to each other, such as travel or attendance at a common event, health care workers say more cases could be out there.

"It's hard to predict but it's always a possibility," said Jocelyn Srigley, associate medical director of infection prevention and control at Hamilton Health Sciences, which runs six hospitals, a cancer centre and an urgent care centre. "Our ERs have dealt with [measles] before." 

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One challenge is training doctors who may have never seen a case of the measles, if they've never travelled to a place where the infection still occurs commonly. 

"In Canada since the mid-2000s it's been very rare to see … out-of-the-blue measles cases where there's no known travel history or exposure history," said David Goldfarb, an assistant professor of pediatric infectious disease at McMaster University. 

Measles can be hard to spot, especially with how infrequently doctors see cases in Canada, and it can be contagious days before a rash appears. Goldfarb emphasized that people should make sure their kid's and their family's immunizations are up-to-date.

"Vaccines are really one of the most effective thing we've ever done in the medical community," Goldfarb said. 

Goldfarb said parents of children who develop a fever and a rash should take their child to the doctor or clinic. 

When an undiagnosed case arrives at hospital

The potential for a measles outbreak echoes some of the concerns raised in recent months as hospitals evaluate their capacity to deal with infectious cases like Ebola. 

"Whether it's Ebola or measles or SARS, a lot of the principles that we follow are the same," Srigley said. "In infection control we have certain tools that we use."

When patients show up to the emergency room or a clinic, they first see a triage nurse, who asks questions about symptoms — fever, respiratory problems, diarrhea, travel history — that helps the staff know whether they should urgently place the person in isolation on suspicion of Ebola or measles. HHS has installed plexiglass shields between patients and those nurses. 

"If they have symptoms suggestive of measles then they would go into airborne isolation," Srigley said. It's a private room that has negative pressure, meaning when a nurse or doctor enters or exits, the virus particles won't seep out into the hallway. 

Elsewhere in the hospital, those isolation rooms have an anteroom, an intermediate room where doctors and nurses can remove their special protective equipment, instead of removing the potentially contaminated items in a public space.

'Those are the other people to think about'

Beyond the precautions that health care professionals take, is there a greater risk to other patients waiting to be seen? That's why triage nurses ask so many questions at the outset, Srigley said. 

But she said with potential measles cases out there undiagnosed, the hospital isn't the only risky place to be. Disneyland was found to be the place of transmission for many of the current measles cases in the U.S., for example.

"I think that's a concern anywhere," Srigley said. "Luckily still the majority of people are immunized."

Goldfarb said he hopes "vaccine resistant" or "vaccine hesitant" people will think not just of their own children but of a child who is younger than a year old, or someone grappling with immunodeficiency or cancer.

"Those people, the vaccines can't protect them very well," Goldfarb said. "Those are the other people to think about." 

Goldfarb feels that concern personally. "I have a 9-month-old who's now at risk whenever we go out in the community," he said.