Fifteen new cases of confirmed human infection of influenza A/H1N1 were reported on Thursday in Canada, bringing the total in the country to 34, including eight patients who contracted the illness in Canada.

An elementary school was closed after one student was found to have caught the disease, becoming the first school to be closed in Canada.

Health officials said although the numbers are going up fast, they will not change their approach in combating the illness.

While all 34 cases are described as mild ones, health officials have warned against complacency, saying the virus may mutate.

A pandemic is highly likely, but it remains unclear how severe it will be, Canada's chief public health officer David Butler-Jones said.

Among the 15 new cases, four were reported in Alberta and Nova Scotia respectively. British Columbia confirmed five and Ontario and Quebec each confirmed one. This has been the first case for Quebec.

Robert Strong, Nova Scotia's chief public health officer, said among all eight cases in his province, only one had been to Mexico and all other seven contracted the virus in Canada.

That brings the total number of human-to-human infection within Canada to eight, with one case already confirmed in British Columbia.

In British Columbia, health officials decided to shut down an elementary school in the Okanagan Thursday after a student fell ill with the virus, one of five new cases in the province, which include two children and three young adults.

Beairsto Elementary school in Vernon, B.C., which organized its students for a trip to Mexico recently, will remain closed for a week, according to the provincial Health Services Ministry.

"The student is experiencing a mild case and is at home recovering well," the ministry said in a statement.

Up to now, among Canada's 10 provinces and three territories, five provinces have reported cases.

At a press conference in Ottawa, Canada's chief public health officer David Butler-Jones announced that the illness, commonly known as swine flu, will now be called the H1N1 flu virus.

The change came after the World Health Organization said Thursday it will stop using the term "swine flu" to avoid confusion over the danger posed by pigs. It will instead refer to the virus by its scientific name, "H1N1 influenza. A."

Butler-Jones also moved to reassure Canadians that despite an increase in cases and the World Health Organization putting the pandemic alert level at 5, a strong signal that a pandemic is imminent, the country is ready should the situation worsen.

"Right now that snapshot shows that a pandemic is highly likely," Butler-Jones said. "How severe it is remains to be seen. But Canadians should be reassured that we are among the most prepared in the world."

Prime Minister Stephen Harper also said Thursday that everything possible is being done to respond to swine flu and encouraged everyone to comply with the advice of health care officials.

"We are all very concerned about the situation," Harper said. "At the same time, people should rest assured that governments around the world are responding to this in an appropriate and co-ordinated way."

But while all of Canada's cases have so far been mild, Dr. David Williams, Ontario's acting chief medical officer of health warned that could change.

"We haven't seen the severe picture that was in Mexico," Williams said. "It does give some ongoing reassurance to some extent, but it's still early and the virus can mutate as well. So while I want to reassure the public that so far it continues to perform in the mild level, I don't think we can be complacent."