Illness in Canada Shows SARS Gaps
Mild Symptoms of Patients Raise a Host
Of Questions; Lab-Test Error Is Possible
An outbreak of respiratory illness at a Canadian nursing home has raised a troubling question: Will SARS come back, and if so, how will we know it?
This week, Canada's top testing laboratory said several elderly patients at Kinsmen Place Lodge, a nursing home in Vancouver, British Columbia, appeared to harbor the virus that causes severe acute respiratory syndrome.
Yet because most of the patients have had only mild, coldlike illnesses, rather than suffering from life-threatening SARS symptoms, the findings have raised a host of questions, including whether the lab tests could be in error to whether a new less-severe form of SARS has been silently spreading.
The mysterious episode underscores big gaps in scientific knowledge and is testing the public-health system's preparedness for a possible resurgence of SARS.
Canadian experts disagreed Tuesday what the results mean. The British Columbia Center for Disease control said its preliminary tests pointed to another human coronavirus, not the SARS virus. But if the Kinsmen virus is indeed SARS, "this is going to impact everyone in the world," said Donald Low, microbiologist in chief at Mount Sinai Hospital in Toronto.
For instance, if SARS can appear with symptoms no worse than the common cold, the coming fall cold and flu season could pose a formidable challenge. If some people harboring the SARS virus become only mildly ill, while others develop the full-fledged disease, "there isn't an easy way to make the diagnosis," says Andrew Simor, chief microbiologist at Toronto's Sunnybrook and Women's College. Controlling the spread of the disease would be harder, since public-health officials can't hope to isolate everyone with a cold.
Hospitals in Toronto say they are prepared for any resurgence. All patients entering the two sites at the Scarborough Hospital, where SARS first began spreading in Toronto, are screened for symptoms and immediately isolated if they exhibit SARS-like symptoms, a hospital spokeswoman said. Staff are asked to screen themselves for any SARS symptoms. Masks and other protective gear would immediately be put into place should any possible SARS cases appear in the city.
Reacting to the report, the World Health Organization in Geneva on Monday sent an epidemiologist to Canada to investigate the outbreak. "We've got some intriguing scientific findings, but not enough information to draw conclusions," said Dick Thompson, a WHO spokesman in Geneva.
The outbreak of respiratory illness in British Columbia apparently started when a staff member became ill at the nursing home on July 3. In a conference call Tuesday, Roland Guasparini, medical-health officer for the Fraser Health Authority in Vancouver, said a total of 94 residents and 49 staff at the Kinsmen Place Lodge took ill with the disease, and currently three staff remain off work and 20 residents remain in isolation as a precaution.
While a small number of elderly patients have developed pneumonia, and six died, most of the cases entailed straightforward cold symptoms, such as runny noses, sore throats, mild muscle aches and fatigue. SARS, in the international epidemic lasting from November to July, caused high fevers and pneumonia in nearly all of its 8,422 victims and killed 916.
Initial tests in the nursing home ruled out SARS, but follow-up tests by Canada's National Microbiology Laboratory detected genetic material identical with that of the SARS virus in several patients. Others had antibodies similar to the virus in their bloodstream, laboratory director Frank Plummer said. Follow-up tests will help determine if the virus is in fact SARS, or perhaps some closely related bug.
The Kinsmen cases raise the possibility that people may be harboring SARS, but showing few or no symptoms.
While many viruses produce both mild and severe infections, SARS is believed to almost always cause severe symptoms. David Patrick, chief epidemiologist at the British Columbia Center for Disease Control in Vancouver, said if the Kinsmen Lodge bug is identical to the SARS virus, "we've been dead wrong about the spectrum of the illness."
Some scientists think another explanation could be less complex. Dr. Simor of Sunnybrook and Women's College said the whole "disconnect" between the mild Vancouver cases and the lab results could still be explained by contamination at the lab. "It would be helpful," he said, "to have corroboration at another lab."
Health officials haven't established any direct link between people in the Kinsmen lodge and any of the four known SARS cases in Vancouver in the spring. But Dr. Guasparini said some of the lodge's staff also worked at the hospitals where the known SARS cases were treated. Investigative work looking for any direct links is continuing, he said.
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