Health officials say there are four cases of swine flu in the Toronto area, but the provincial medical officer of health considers them to be an extension of flu season.

"All the cases we've seen so far are mild, self-limiting, so it's like flu season continuing," Dr. David Williams told a Tuesday news conference.

All four cases are mild, "meaning they did not require hospitalization," he said, adding the individuals had been to Mexico.

"Personally, I know we're going to see a lot more cases. It's only a matter of time because of the amount of flow of public that go back and forth to Mexico," Williams said. "It would not be surprising that we have some more confirmed cases."

Three of the newly confirmed cases are in Durham region. All three are women in their 20s. One 27-year-old man lives in York region.

The cases are the first ones to be confirmed in Ontario. On Monday, officials said there were 10 to 12 suspected cases. Williams said Tuesday that number is now 20 cases but is likely to change so rapidly.

Earlier Tuesday, city officials said there had been no cases of swine flu detected so far in the city of Toronto.

 Dr. David McKeown, the city's medical officer of health, told the morning news conference that health officials are "ready to respond" in the event of an outbreak here.

He also asked that anybody who recently travelled from an infected area and is experiencing flu symptoms to contact their doctor for an assessment.

Toronto Mayor David Miller credited the city's experience with SARS -- a deadly respiratory illness that plagued the city in 2005 -- for its readiness to deal with other infectious diseases.

So far, there are 13 confirmed cases of swine flu in Canada.

Health officials say that increased influenza monitoring has been put in place, asking area hospitals to immediately report possible cases of swine flu.

Ontario Premier Dalton McGuinty also tried to soothe people's fears Tuesday, assuring the public that the province's health system is in a strong position to deal with a crisis, should one arise.

"There's a real concern here, there's no doubt about that, but it's not a cause for undue alarm," he said.

He too credited the SARS crisis for forcing the province to have an effective plan for disease control.

"I want to reassure our families that... all of our public health officials, and our doctors and nurses, are working hard and well together, executing a plan we have put in place drawing on the painful lessons that we learned six years ago," he said.

"We have a new plan, we have more resources, we have more personnel, more technology, more know-how and a better understanding of how to deal with these kinds of things."

What to do

Williams said that swine flu appears to be spread much like colds and other respiratory viruses.

As preventive measures, people should wash their hands frequently and cough or sneeze into their sleeve and limit contact with family members, he said.

Those Ontarians who have general questions about swine flu can call the ServiceOntario INFOline at 1-800-476-9708.

If someone has flu-like symptoms and believe they may have swine flu, they should call Telehealth at 1-866-797-0000.

Symptoms include:

  • fever
  • cough
  • fatigue
  • muscle aches and pains
  • vomiting and diarrhea (in some cases)

If people feel ill, they should stay away from work and consult with their physician, he said.

Mexico still a hot spot

Ontario Ministry Health officials spoke hours after the federal government issued a travel warning advising people against travelling to Mexico.

Mexico's residents have been hit hard by the virus as the flu is being linked to more than 150 deaths.

But despite the warnings, many Canadians crowded Pearson International Airport Tuesday afternoon, eager for a vacation.

"We'll just be careful and wash our hands and take precautions," said one woman waiting in line to check her luggage. "But we're looking forward to the change."

Dr. Donald Low, an infectious disease specialist in Toronto, told CTV Toronto that young, healthy people should have a strong enough immune system to fight the disease should they contract the virus on vacation.

"What we want to make sure is that they don't bring it back home with them," he said.

The swine flu outbreak has not reached pandemic proportions but health officials warn that the virus is spreading quickly from person to person.

"We're not talking about 1,000 cases, we're talking tens of thousands of cases or maybe hundreds of thousands of people that have had this disease," said Low. "The number of deaths that are being reported is making it seem like this is a virus that causes a high death rate."

There have been reported cases of swine flu in Canada, the U.S., the Middle East, Europe and in Mexico.

With a report from CTV Toronto's Reshmi Nair and files from The Canadian Press