With a possible new SARS case in Singapore, regular rumors of outbreaks in nursing homes and hospitals in former SARS hot spots and flu season around the corner, public health officials need to figure out how and when physicians and hospitals should ring alarm bells, experts say.

To that end, Health Canada is calling together officials from Ontario and British Columbia -- the two provinces which had SARS outbreaks -- as well as the US Centers for Disease Control and the WHO to try to establish guidelines for SARS surveillance for the coming cold and influenza season.

Coming up with workable framework is not going to be easy, admitted Dr. Arlene King, director of Health Canada's immunization and respiratory infections division.

"It's challenging. There's no question about it. This is not an easy subject," she said in an interview with local reporters.

One of the key questions that will be on the table during the meeting to be held Wednesday and Thursday in Ottawa is when should doctors order SARS testing to be done?

Tests for the SARS coronavirus are still new and have not been validated. It remains unknown how often they produce false positives or false negatives.

But a positive SARS test demands instant action and draws worldwide attention. That's something public health officials in British Columbia learned to their dismay last month when they were trying to figure out what was behind an outbreak of mild respiratory illness at a seniors' home in Surrey, south of Vancouver.

The illness didn't look like SARS, which has a mortality rate of 50 percent in people aged 60 and older. The average age of residents of the lodge was 82, but most of those who became ill just experienced cold-like symptoms.

SARS has since been ruled out as the cause of the outbreak. But the incident points out how crucial it is that doctors and public health authorities across the country get some guidance about when SARS testing should be conducted, said Dr. Donald Low, a leading SARS expert.

In addition to setting out criteria for when SARS tests should be conducted, the experts at the meeting are expected to finalize new Canadian case definitions for suspect and probable SARS.

(Xinhua News Agency September 11, 2003)