Health-care workers on the front lines of Canada's preparations for the new coronavirus are gearing up to treat potential infections and prevent spread.

Those preparations will continue regardless of whether or not the World Health Organization declares the outbreak spreading in and beyond China a global health emergency on Thursday. The agency was expected to make a decision on Wednesday but delayed, citing lack of information.

China remains the epicentre of the outbreak, with more than 500 cases. Thailand, the United States, Taiwan, South Korea and Japan have also confirmed cases.

The head of the WHO's health emergencies program, Mike Ryan, said the priority now is to find out how the virus is passing between people and to limit it.

"We are in agreement with Chinese authorities who have been clear and transparent that there is evidence of human-to-human transmission," he said.

Given the speed of global travel, Canadian officials have said they would not be surprised if the virus lands here. If so, airport screening would offer one measure in efforts to control the spread. But passengers arriving here may not show any symptoms for days, which is why hospitals and health-care officials are getting ready.

"We are certainly preparing for the potential of a first case in Canada," says <a href="https://twitter.com/CPHO_Canada?ref_src=twsrc%5Etfw">@CPHO_Canada</a> Dr. Tam, as the deadly coronovirus outbreak in China continues to spread. She says it's "not surprising" the U.S. has detected a case, given the heightened alerts to local health systems. <a href="https://t.co/TCIuQApWD3">pic.twitter.com/TCIuQApWD3</a> —@PnPCBC

Standard infection control practices like isolating potentially sick patients are key, experts say.

At Toronto General Hospital's emergency department, staff have already had some practice in the form of three patients who tested negative.

"We've had three patients come in with a travel history who presented with these symptoms," said nurse Debra Davies, the manager of the emergency department. "They've done a phenomenal job in getting those patients into the isolation."

"As long as we keep an eye on it, we should be well prepared," she said.

Davies is a veteran of the SARS outbreak in 2002-03 that infected more than 400 people in Canada and killed 44.

A staff member screens arriving passengers with thermal scanners at Hankou railway station in Wuhan, in central China during the high-travel season for Lunar New Year. (AFP/Getty)

Dr. Michael Gardam, chief of staff at Humber River Hospital in northwest Toronto, says there were lessons learned from SARS.

"I can't stress enough how incredibly unprepared we were for SARS," he said. "We're in such a better position now."

During that outbreak, Gardam recalls running around trying to buy respirators and setting up negative pressure rooms to isolate patients. When Humber River opened in 2015, it was designed with outbreaks and infection control in mind, and such equipment and design principles are built into the new hospital.

Horacio Arruda, head of Quebec's public health authority, said Wednesday five people in that province were under surveillance for possible exposure.

Hospitals in Nova Scotia, Saskatchewan, Alberta and British Columbia have also announced preparations for cases.

Airport screening

The Public Health Agency of Canada (PHAC) acts as the lead agency for dealing with the coronavirus, through the Quarantine Act.

Under PHAC's direction, Canada Border Services Agency officials will now ask travellers: "Have you been in Wuhan, China, in the past 14 days?" There are no direct flights from Wuhan to Canada.

Additional signs at airports in Toronto, Montreal and Vancouver will remind passengers to speak to border officials if they have flu-like symptoms such as fever and cough.

Health officials watch thermographic monitors at a quarantine inspection station at the Kuala Lumpur International Airport in Malaysia on Tuesday in the hope of identifying passengers infected with the new coronavirus. (Vincent Thian/The Associated Press)

"We are in the process of putting up signs on the electronic screens warning travellers that if they've been to an affected area to essentially determine if they've been in contact with live animals, sick people," Dr. Theresa Tam, Canada's chief public health officer, said Tuesday on CBC's Power & Politics.

If so, CBSA agents can alert a federal quarantine officer to do an assessment, which could include a temperature check.

Digital signs were added Wednesday at Vancouver International Airport to warn travellers to be aware of the new coronavirus infection circulating. (Vancouver Airport Authority)

Canada's National Microbiology Laboratory as well as provincial government labs in Ontario, British Columbia and Alberta have a battery of tests to detect respiratory pathogens, including one that's in the works for the new coronavirus, Allen said.

So far, Canada is not planning to use thermal imaging to monitor travellers en masse, as was tested during the SARS outbreak.

Small percentage

Tam said the current assessment of the risk to Canada is "low."

Steven Hoffman, a law professor and director of the Global Strategy Lab at Toronto's York University, and an expert on global health, supports Canada's screening approach so far.

"Not everyone who has a high temperature is going to have this novel coronavirus. In fact, only a very small percentage would," said Hoffman.

Dr. Kamran Khan, an infectious disease physician, says the most important point of screening travellers is 'giving them the information they need so that if they do become sick after they've left the airport they know what to do.' (John Lesavage/CBC)

The first U.S. patient illustrates one of the weaknesses of airport screening — the man in his 30s did not have symptoms when he arrived and was in good condition, so he wouldn't be picked up in a check for fever.

Rather, when the man started feeling ill, he went to a doctor, with a fever and cough. Lab tests confirmed the infection and he was put into isolation for monitoring.

Engaging travellers

Dr. Kamran Khan, an infectious disease physician in Toronto, said there's a delay between when people are infected and when they develop symptoms — the incubation period. For coronaviruses in general, such as those that can cause the common cold, the incubation period is typically five or six days.

With coronaviruses such as SARS and Middle East Respiratory Syndrome, MERS, the incubation period can extend to 14 days.

"You can imagine if an individual is infected and they get on a plane and it could be up to two weeks before they manifest symptoms. In today's world you could literally go around the Earth before you start to develop illness," said Khan, founder and CEO of BlueDot, a digital health company that helps predict the spread of infectious diseases globally.

"We need to kind of think about that in the context of how airport screening works. The value of airport screening and engagement with travellers, if you will, is more about giving them the information they need so that if they do become sick after they've left the airport they know what to do."

Health officials stress precautions for travellers to prevent infection while in China, such as staying away from animal markets, washing hands, observing cough hygiene, not coming into contact with sick people and telling health-care providers about their travel if flu-like symptoms occur.