Students wear masks on the campus of King's-Edgehill School in Windsor, N.S., on Monday. Four students from the school contracted swine flu after an exchange trip to Mexico's Yucatan Peninsula. (Andrew Vaughan/Canadian Press)

Canadians should expect to see more severe cases of swine flu — including some deaths from the virus — as the outbreak spreads, the country's chief public health officer warned Monday.

"Simply because we are seeing mild cases so far does not mean we can take this for granted," said Dr. David Butler-Jones during a news conference in Ottawa with federal Health Minister Leona Aglukkaq.

"We will likely see more cases, we will likely see more severe illnesses and we will likely, unfortunately, see some deaths as well. We hope not, but it is a normal part of an influenza outbreak."

There have been six confirmed cases of swine flu in Canada since the outbreak was first reported in Mexico. All six people — four in Nova Scotia and two in B.C. — had a mild form of the illness and have recovered, Butler-Jones said.

Along with the cases in N.S. and B.C., medical authorities in Ontario, Prince Edward Island, Quebec and Saskatchewan are investigating cases of suspected swine flu.

Canada has heightened its surveillance system to more closely monitor the spread of the disease and will focus on rigorous infection control, he said.

The government is also considering advising travellers against all non-essential travel to Mexico, said Aglukkaq.

Provinces test for swine flu

Ontario deputy premier George Smitherman told reporters on Monday that about 10 to 12 potential cases of swine flu in the province are being checked.

"We first of all want to identify, we want to contain, we want to control any possible infectious outbreaks," Smitherman said.

Minister of Health Leona Aglukkaq told MPs in the House of Commons on Monday that Canada is "well-positioned" to deal with swine flu. (Sean Kilpatrick/Canadian Press)

Dr. Donald Low, medical director of Ontario's public health laboratories and chief microbiologist at Toronto's Mount Sinai Hospital, told CBC News he suspects the cases will be identified in the next 24 to 48 hours.

"We're in a unique opportunity in history that we're watching, I think, a pandemic unfold," said Low, who provided regular updates to the public during the SARS crisis six years ago.

"I don’t think anybody's thinking that this is not across Canada."

In P.E.I., the province's chief health officer Dr. Heather Morrison said Monday eight people who recently returned from Mexico are being tested for human swine flu and have been asked to isolate themselves.

In Saskatchewan, the province's chief medical health officer Dr. Moira McKinnon said eight people who showed flu symptoms had been tested. The results for five came back negative and the other three have been asked to stay home and have been prescribed the anti-viral medication Tamiflu.

Public health officials in Sherbrooke, Que., are following one suspected case of swine flu in a local resident who returned from a trip to Mexico with flu symptoms.

Canadians should take precautions

Aglukkaq has urged Canadians to take precautions to prevent the human-to-human transmission of this strain of swine flu by washing their hands with hot water and soap, as well as covering up their mouth and nose when sneezing.

She also advised people to stay home and contact their family physicians if ill, particularly if they've recently visited Mexico and have flu-like symptoms.

Aglukkaq said she is in regular contact with officials at the WHO, as well as her counterparts in the U.S. and Mexico. The government is also working "very closely" with the provinces and territories, she said.

"Canada is well-positioned to deal with the issue," she said during question period in the House of Commons on Monday. "We have a national plan to deal with disease outbreaks."

The federal government also said Monday it does not plan to ban seasonal workers from Mexico from entering Canada, but will require they have enhanced medical checkups before leaving Mexico.