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.
The terrifying outbreak of SARS in 2003, which left 44 dead in the city, is very much on everyone’s mind.
The Seven Oaks home has instituted full-scale infection control measures, including a ban on visitors. Staffers caring for the residents are masked, gowned and gloved.
Also, the home has instituted what Dr. McKeown called “cohort nursing,” in which groups of residents are consistently cared for by the same staff members to minimize contacts that might spread infection.
The eight hospitals that have admitted sick residents are also following the strict protocols for respiratory illnesses put in place during the SARS outbreak.
The response shows that the public health officials have learned their lesson, said Allison McGeer, M.D., the head of infection control at Toronto’s Mount Sinai Hospital, earlier this week.
“SARS gave everyone new respect for respiratory viruses,” said Dr. McGeer, who not only was one of the leaders in the struggle against SARS, but also contracted the virus at the height of the outbreak.
Dr. McKeown said earlier this week that SARS led to “much better protocols for dealing with respiratory outbreaks.”
As well, public health officials are working more closely with ambulance services, nursing homes, and hospitals than was the case in the first few weeks of the SARS outbreak, he said.
The Toronto SARS outbreak was eventually linked to a single index patient, a 78-year-old woman who had apparently contracted the disease during a visit to Hong Kong. In the current outbreak, Dr. McKeown said, officials have been unable to identify an index patient.
“It’s difficult to pinpoint a source,” he said.
However, like SARS at the beginning, this virus remains a mystery. Dr. McKeown said he and other officials are hoping that testing will eventually pinpoint it.
SARS is caused by a new member of the coronavirus family (the same family that can cause the common cold). The discovery of these viral particles represents some of the fastest identification of a new organism in history.
SARS is clearly spread by droplet contact. When someone with SARS coughs or sneezes, infected droplets are sprayed into the air. Like other coronaviruses, the SARS virus may live on hands, tissues, and other surfaces for up to 6 hours in these droplets and up to 3 hours after the droplets have dried.
But, he added, “in most outbreaks of this sort, the virus is never identified.”
So far, the illness has not spread beyond residents, staff members and visitors of the nursing home, Dr. McKeown said, although the hospitals involved are taking strict respiratory precautions.
“We’ve spoken to a large number of people who were in the facility during the time when the outbreak was happening,” he said. “Very, very few of them have any illness at all and none is seriously ill.”
“That’s a sign, I think, that there’s very little risk of this infection coming out into the community,” he said.
Revision date: June 22, 2011
Last revised: by Janet A. Staessen, MD, PhD