Flu expert’s answers

Finding the respiratory virus that is causing residents of Seven Oaks Home for the Aged to get sick and in some cases die is like finding a needle in a haystack and may prove difficult for even the most diehard of medical detectives, like Dr. Allison McGeer. That’s because it could be one of hundreds of respiratory bugs. We asked McGeer, a microbiologist at Mount Sinai Hospital and director of infection control, about the mystery bug that is affecting the elderly and staff at the Scarborough nursing home. Q: What is this mysterious illness? A: This illness appears to be what we think of as a “usual” respiratory virus. There are a whole group of viruses that are characterized by the fact they have the same incubation period, they cause the same kind of illness, the same kind of infectivity and the modes of transmission are the same. They are impossible to distinguish from each other. . . . We may or may not identify this before we stop investigating. When you get these infections, they damage the lining of the passages in your lungs. There’s inflammation and irritation. So if you have asthma or underlying lung disease, it gets worse. For reasons we don’t understand, they also set off heart attack and make people’s angina worse. . . . You’re also more likely to get infections from pneumonia and other infections that complicate the condition. . . . Healthy people get common colds and are miserable for three or four days, maybe a week. People who are elderly and have serious underlying problems are more likely to get more complicated illnesses from the virus. Q: Should the public be concerned in any way? A: No. There is nothing at the moment in this outbreak that suggests it is anything new, worrisome or different for the general public. It is, however, a very good reminder about how fragile our elderly population, particularly in nursing homes, is. Q: How often do outbreaks of these kinds occur in nursing homes and what is the mortality rate? A: Outbreaks of these respiratory viral infections occur very commonly in nursing homes. We have about 600 nursing homes in Ontario and, depending on how much virus activity there is in a year, somewhere between 25 and 75 per cent of nursing homes have outbreaks. Usually in those outbreaks, between 10 and 15 residents are affected. The mortality rate is about 5 per cent, sometimes a little higher. Q: Is it SARS or anything like SARS or influenza? A: The first thing you do is to demonstrate it’s not influenza, and in this case it’s not. Then you want to make sure it won’t get out in the community, like SARS or avian flu. We know it’s not that. We have tests for that. And we’ve tested for that and those tests are negative. . . . We’ve got a bunch of tests for other viruses that are common and relatively easy to test for, but everything we’ve looked at so far is negative.