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Canadian labs can't confirm
SARS-cold virus link

FROM CANADIAN PRESS

A previously unidentified member of a family of viruses that causes cold-like ailments in humans was identified today by the U.S. Centers for Disease Control as the leading suspect in the search for the source of SARS.

"Right now for us this is a hypothesis. It is our leading hypothesis," CDC director Dr. Julie Gerberding said at a news conference in Atlanta.

Gerberding said CDC scientists have been able to isolate the virus from specimens from some SARS patients and have been able to grow it in culture.

As well, blood samples taken at different times in the course of the illness show at least some patients have no antibodies against the virus early in the disease process but go on to develop them. That suggests the virus is not something they have been carrying for some time, but has mounted a new assault on their immune systems.

But the head of Health Canada's national microbiology laboratory in Winnipeg said scientists there have been unable to replicate the results that lead the CDC to believe a new coronavirus is behind the mysterious outbreak.

"We've been aware of these results for a couple days and as yet we've not been able to confirm the results," said Dr. Frank Plummer, scientific director of the laboratory.

"Our results were negative for coronaviruses. And we continue to find evidence of human metapneumovirus."

On Friday, Plummer announced his team had found human metapneumovirus, a member of the paramyxovirus family, in specimens from six of eight patients for whom the lab had samples.

Scientists in Hong Kong had named the paramyxovirus family earlier in the week as the likely causative agent.

To date a number of labs have found evidence to support the Winnipeg laboratory's findings. And scientists at the University of Hong Kong have found evidence to back the coronavirus hypothesis.

Regardless of which is to blame — if indeed one of the two is the culprit — the findings are surprising. Both types of viruses are known to mainly cause mild cold-like ailments. No one is clear on why one or the other of these viruses may have become a killer.