Four More Deaths From Canadian Mystery Virus, but Outbreak Wanes

Despite four newly reported deaths, health officials here say they're "confident" a mysterious viral illness, which causes respiratory symptoms, is under control.

"The outbreak remains under control," said David McKeown, M.D., of Toronto's Medical Office of Health. "The good news is that the number of new cases has really dropped off."

But he said the outbreak, centered on a nursing home in the eastern part of the city, has now killed 10, most of them frail and elderly, has made 70 of the home's 250 residents ill, and has sent 40 of them to the hospital.

Also, 12 staff members of the Seven Oaks Home for the Aged have fallen ill, and follow-up calls to people who had visited the home in the days before the outbreak was recognized found two with symptoms consistent with the mystery virus, Dr. McKeown said at a late afternoon press conference.

He said he "would not be surprised to see additional deaths" among those already ill.

But, he added, the number of new cases continues to fall; there had been no new cases by 4 p.m. today, and just two on Monday, down from a peak of 20 on Sept. 29.

Those who died, for the most part, were "very elderly, frail, and have other medical conditions," he said.

The four newly reported deaths include three women and a man, all in their 80s and 90s, he said. Three of the deaths occurred Monday; the other occurred Sept. 30 and was included retrospectively after a case analysis, he added.

The cause of the illness remains unclear. Scientists carried out autopsies Monday on the first four of those who died, and were analyzing lung tissue samples today in the hope of identifying the virus, whose symptoms are cough, fever and malaise.

Officials have already ruled out influenza, Avian flu, and Severe acute respiratory syndrome (SARS), and a range of other common viruses.

Severe Acute Respiratory Syndrome (SARS) is a serious form of Pneumonia, resulting in acute respiratory distress and sometimes death. It is a dramatic example of how quickly world travel can spread a disease. It is also an example of how quickly a networked health system can respond to an emerging threat.

This contagious respiratory infection was first described on February 26, 2003. SARS was identified as a new disease by World Health Organization (WHO) physician Dr. Carlo Urbani. He diagnosed it in a 48-year-old businessman who had traveled from the Guangdong province of China, through Hong Kong, to Hanoi, Vietnam. The businessman died from the illness. Dr. Urbani subsequently died from SARS on March 29, 2003 at the age of 46.

But Dr. McKeown said so far researchers at the Ontario Public Health Laboratories have not come up with a smoking gun.