The
virus pinpointed as the likely cause of the killer Sars illness
may not be responsible - most Canadian victims don't carry
it. So far, more than 4,000 people worldwide have fallen ill
with Sars, which kills in 4% of cases.
In
Canada, more than 300 are either "probable" or "suspected"
of having sars, and 15 are reported to have died.
The outbreak centres around the city of Toronto.
The World Health Organization says it is reasonably certain
that Sars is caused by infection with a new strain of coronavirus.
However, Canadian scientists have carried out hundreds of
tests on samples from patients with suspected or probable
cases of Sars in Canada.
They found only 40% of people carried the new strain of coronavirus.
In addition they found evidence of the strain in healthy people
enlisted as "controls" for the experiment.
Nine out of ten
The results, from the Canadian National Microbiology Laboratory
in Winnipeg, completely contradict those from scientists in
Hong Kong, where more than 100 people have so far died from
the illness.
The Hong Kong team found that 90% of probable Sars cases harboured
the coronavirus, and found no trace of it in healthy controls.
Researchers around the world are scrambling to provide diagnostic
tests and treatments, and even working towards vaccines, on
the basis that coronavirus is the root cause.
If it is not actually caused by coronavirus, then these efforts
would be in vain.
Many experts believe it will be some years before an effective
vaccine for this new strain of coronavirus is available.
Dr Frank Plummer, who led the Canadian research, said: "There
remain some very puzzling things we are finding.
"I'm still not convinced it's coronavirus - although it could
well be, but the data is not conclusive."
BBC
News
Last Updated: Wednesday, 23 April, 2003
16:58 GMT
In
Canada, more than 300 are either "probable" or "suspected"
of having sars, and 15 are reported to have died. 
