Updated

A mystery flue-like illness has killed a fifth and sixth person in Canada and appeared to be spreading throughout the country, health officials said Tuesday.

Ontario health authorities announced the deaths the same day that Canada's health minister acknowledged that little is known about severe acute respiratory syndrome, or SARS, but said proper steps have been taken to confine it.

All the deaths in Canada have occurred in Toronto, where the majority of the nation's 151 probable or suspected cases so far have occurred. The total announced by the federal health department included 22 more than the previous day, with possible cases for the first time on Prince Edward Island in the east.

The illness was brought to Canada by air travelers from Asia. Its initial symptoms include fever, dry cough and shortness of breath.

SARS has killed more than 60 people worldwide and sickened about 1,800, with the majority of cases in Hong Kong and China.

Health Minister Anne McLellan said information cards and questionnaires have been given to international travelers at Toronto's Pearson International Airport, but interviewing the 36,000 international travelers using the airport each day would be unworkable and unnecessary.

Prime Minister Jean Chretien called the SARS outbreak "a very serious problem" but added, "We should not panic. We hope it is confined, but you never really know."

In Ontario, the nation's most populous province, authorities have declared a health emergency and restricted access to all hospitals, where staff and visitors must wear masks and other protective garb.

Anyone with symptoms, anyone who has been in contact with SARS patients or anyone who visited two hospitals where the illness first turned up have been asked to quarantine themselves at home for 10 days.

Federal health officials say there are 124 probable or suspected cases in Ontario, with others in Vancouver on the west coast, the prairie provinces of Alberta and Saskatchewan, and Prince Edward Island and New Brunswick province on the east coast.