Canada confirmed its first "presumptive" case of coronavirus in Toronto as the number of infections worldwide surpasses 1,900 cases.

Public health officials announced Saturday afternoon the patient — a man in his 50s who had travelled to Wuhan, China — was found at Toronto's Sunnybrook Health Sciences Centre.

Within a day of arriving, officials say, he became "quite ill," said Dr. Barbara Yaffe, associate chief medical officer of health with the provincial Ministry of Health.

Officials say lab results were received Saturday afternoon. The man is in stable condition.

While the case has been confirmed by a test in Toronto, officials said it has yet to complete separate testing by the National Microbiology Laboratory in Winnipeg. The illness can't be officially confirmed until that testing is completed.

Watch: Health officials say they have the situation 'well-managed.'

Toronto’s medical officer of health Dr. Eileen de Villa says a team is tracking down those who might have been in contact with the man, whose family members are already in self-isolation. 0:53

What do we know about the case?

Officials said the man took a flight on Jan. 21 from Wuhan to Guangzhou, then from Guangzhou to Toronto, arriving on Jan. 22.

Dr. Theresa Tam, Canada's chief public health officer, said the patient showed mild symptoms on the flight, but did not report his flu-like symptoms upon arrival.

He is believed to have travelled "privately" from the airport to his home. Officials do not believe he took public transit. They have not said what part of the city the man lives in.

Upon arriving, he told family members he felt ill and called 911. Officials say paramedics arrived prepared, taking all necessary precautions "right from first contact" until the hand-off to the hospital's emergency department on Jan. 23, officials say.

Watch: An associate professor at U of T's faculty of medicine discusses what comes next.

Dr. Susy Hota, associate professor at the University of Toronto's faculty of medicine, reacts to the news following the confirmation of the first "presumptive" case of the coronavirus in Toronto. 5:22

But in a tweet following Saturday's news conference, the Toronto Paramedic Union said the first responders who transported the man only learned he was infected with the coronavirus after they had transported him.

"Why did @TOPublicHealth not notify the division? This is completely unacceptable," said the tweet, which has since been deleted.

Toronto Public Health issued a statement in response saying it does not notify paramedics about patient lab results if they have not been exposed to a public health risk.

"In this situation, the paramedics used full personal protective equipment and no followup was therefore necessary," said the statement from Dr. Rita Shahin, associate medical officer of health.

Public health officials announced Saturday Canada's first presumed case of the coronavirus at Toronto’s Sunnybrook Health Sciences Centre. (Yanjun Li/CBC)

The union later sent a pair of followup tweets, confirming that the division was notified by Toronto Public Health "of a change in condition to a patient that paramedics transported...

"Paramedics were fully protected during the emergency call. It remains unacceptable that they were not informed of the change in condition prior to the media release."

When the man arrived at Sunnybrook, hospital officials say he was immediately identified as possibly affected by the virus and placed into a negative pressure room to prevent any contamination, with health-care workers taking protective measures to ensure the safety of staff and other patients.

What's the likelihood it will spread?

Public health officials are now working to track down some of the passengers of the China Southern Airlines flight after learning that the man showed symptoms on the plane.

Federal authorities, together with Toronto Public Health, are in the process of reaching out to those who were within a two-metre radius to the man to ensure they know what to do if they become ill, she said.

Officials are also trying to determine exactly how much contact the man could have had with others since his return to Canada. Officials say any contact was likely limited to members of his household.

Anyone who lived with the man is currently in "self-isolation," said Yaffe.

Watch: Health officials discuss whether people on the same flight are at risk.

Health officials say they need to reassess the patient's risk of being contagious while on board a flight to Toronto. 0:50

The federal government says it has been working with provincial, territorial and international counterparts since China first began reporting cases to make sure Canada is prepared to limit the spread of the infection.

"Canadian hospitals have strong infection control systems and procedures in place to limit the spread of infection and protect health-care workers," said federal Health Minister Patty Hajdu, who is expected to hold a news conference on Sunday morning.

What does 'presumptive' mean?

Health officials referred to the case as "presumptive" because they're being cautious due to the detailed process of testing and validating the sample, said Dr. Allison McGeer, an infectious disease specialist at Mount Sinai Hospital in Toronto.

When testing for a typical virus, technicians with the Public Health Ontario Laboratory would compare the sample with positive and negative specimens in order to verify a positive result, she said.

Sunnybrook Health Sciences Centre is caring for a patient who has a confirmed case of the novel coronavirus that originated in Wuhan, China.<br><br>The patient is in stable condition and has been admitted to an isolation room. More info: <a href="https://t.co/BDLgqfjAzw">https://t.co/BDLgqfjAzw</a> —@Sunnybrook

But because the test for the new coronavirus was developed so quickly based on positive cases overseas, it's standard practice to have two laboratories verify the sample.

"You never call something definitive until two labs with two different tests have called it," McGeer said.

"It would be really surprising if it wasn't confirmed."

How deadly is the virus?

Dr. David Williams, chief medical officer of health for Ontario, told the news conference that the province's health system acted as it should.

"As a result, the risk to Ontarians is still low, and things are managed and well-controlled," Williams said.

It is not clear how lethal the new coronavirus is or even whether it is as dangerous as the ordinary flu, which results in 12,200 hospitalizations and about 3,500 deaths in Canada yearly.

At this point, the World Health Organization has not declared the outbreak to be an international public health emergency.

So far, there have been 76 reported deaths attributed to the virus, all in China, according to China's state media.

The majority of those infections have been inside China, where the virus has mostly been concentrated in Wuhan city, although there have been confirmed cases reported in Shanghai and Beijing, along with Hong Kong and Macao.

Outside of China, cases have been confirmed in France, Japan, South Korea, Taiwan, Thailand, the United States, Vietnam, Australia and Malaysia.

In China, transportation has also been shut down in roughly a dozen cities, home to roughly 36 million people. Canadian officials have said such mass quarantines are unlikely, even if the virus spread here.

What do we know about this virus?

Coronaviruses are a large family of viruses that most often cause mild-to-moderate upper respiratory tract illnesses including the common cold, but they can also lead to severe diseases. Some coronaviruses spread between animals, some pass between animals and people, and others go from people to people.

Watch: Health officials discuss what precautions people can take.

Ontario Health Minister Christine Elliott says people are encouraged to take normal precautions such as washing hands and coughing into their elbow to prevent transmission of any kind. 0:51

This new virus is different from the coronaviruses that cause Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS).

Its symptoms include fever, cough and difficulty breathing.

Typically, coronavirus infections manifest as the common cold. Symptoms can include runny nose, headache, cough, sore throat and fever. Young babies may contract gastrointestinal disease. Severe cases involve pneumonia, kidney failure and even death.

Those with weakened immune systems are most vulnerable to severe disease. That includes the elderly and people with chronic illness, such as diabetes, cancer, heart or lung disease.

Those travelling to China, where the majority of infections have happened, are advised to avoid crowded areas and seek medical attention if they become sick. The federal government advises avoiding farms, live animal markets and contact with animals alive or dead, in addition to usual precautions.

What now?

Confirmation of this case comes just one day after Williams said it was only "a matter of where and when" the virus would arrive in Canada.

"Ontario is ready, our systems are ready," Williams said in a news conference Friday. "We're light years away of where we were in 2003," he said, referring to the SARS outbreak that killed 44 people in the Toronto area.

Watch: Health officials say they're better prepared than they were for SARS.

Experts say Canada is much better prepared for the new coronavirus than it was for SARS in 2003. 0:40

Dr. Peter Donnelly, CEO of Public Health Ontario, said Friday the province has testing that lets medical professionals know within 24 hours whether an illness is this new coronavirus type.

Toronto Mayor John Tory said he has "complete confidence" in the city's medical officer of health, Dr. Eileen de Villa, to co-ordinate the city's response. "Our front-line health-care workers are the best in the world and have procedures in place to keep people safe," Tory said in a statement.

"Toronto Public Health is continuing to work closely with provincial and federal health colleagues to actively monitor the situation and respond as appropriate."

(CBC News)

The federal government says measures to stem the risk and spread of diseases like the coronavirus are in place.

These include messages on arrival screens at the Toronto, Montreal and Vancouver international airports reminding travellers to inform a border services officer if they are experiencing flu-like symptoms, as well as an additional health screening question on electronic kiosks used by international travellers.

If need be, officials say passengers will be referred to local hospitals, with the individual's travel history available to the hospital they may arrive at.

British Columbia's minister of health and provincial health officer said there have been no cases in B.C. and the overall risk to the province is still low. ""We are closely watching the situation in Canada and globally and are meeting regularly with our counterparts across the country to make sure we are prepared if cases arise in B.C.," Adrian Dix and Dr. Bonnie Henry said in a statement issued Saturday.

Watch: Full statements by health officials on presumptive coronavirus case.