Canadian, U.S. scientists debate cause of SARS

Researchers in the United States went public Monday with their hypothesis on a cause for the mysterious pneumonia-like illness.

Scientists in Geneva and the U.S. have seen a coronavirus, a family of viruses that includes the second most common cause of colds.

Last week, microbiologists at the National Microbiology Laboratory in Winnipeg identified genetic signs of human metapneumovirus, a family of microbes that can cause measles, mumps and canine distemper.

• FROM MARCH 21, 2003: Canadian scientists find clue in SARS outbreak

"We now have two major groups and it's up to the laboratories to see where the virus is going to end up," said Dr. Klaus Stohr, a WHO virologist who is co-ordinating the laboratory work.

Dr. Julie Gerberding, director of the U.S. Centers for Disease Control and Prevention said Monday it appears a new form of cornovirus has been found in the lungs and other tissue of some victims. Patients also seemed to develop antibodies to the virus as they get sicker with pneumonia, she said.

It could also be a combination of both viruses, or neither. It is too early to tell, and experts say finding the virus in tissue samples does not mean it is the cause.

The illness, called severe acute respiratory syndrome, SARS, has produced 456 cases and 17 deaths since Feb. 1, WHO said. The figures do not include an earlier outbreak from mainland China.

Scientists want many lines of evidence, such as electron microscopy images, genetic sequencing of the virus, and immunology results, before they can be confident about identifying the cause of SARS.

Teams of researchers from around the world are sharing their knowledge and findings with each other to gain clues to the cause of SARS and identify the best treatments.

Despite the spirit of co-operation, there simply aren't enough samples from all cases to go around.

Researchers in Hong Kong have developed a test to diagnose SARS, which is now being perfected for clinical use.

The WHO has said it appears "that the test is reliably identifying cases of SARS infection." Gerberding said more research needs to be done to see how accurate and sensitive the test is.