As winter approaches, we can begin to worry about frostbite instead of mosquito bites. After all, it would seem the 2002 West Nile virus episode is coming to a close.

But rest assured, in eight months it is bound to return, for the West Nile Virus is in North America to stay.

Even though Canadians have only taken note of the disease recently, the West Nile virus has actually been around for some time. First discovered in Uganda in 1937, this mosquito-borne pathogen (Flaviviridae flavivirus) slowly spreads its way across temperate regions of the Middle East, Europe, Asia, South America, and most recently in North America, starting with New York City in September 1999.

Since then, U.S. and Canadian scientists, health officials and the media have begun to seriously monitor the activity of the West Nile virus. Every summer, there are increasing concerns as fatal consequences befall the horse, dog, cat, squirrel and bird populations.

West Nile was first detected in Canada in June of 2001. Organizations like the Canadian Cooperative Wildlife Health Centre have kept a close watch on wildlife and dead birds ever since. In Ontario, the virus is known to affect more than 70 species of birds, including crows, ravens and bluebirds.

This year, the virus claimed its first human life in Ontario, a Mississauga resident. Twenty-nine people in Canada have been confirmed infected.

Should we worry?

“The probability of any one of us getting sick, because that’s what we care about, is low, but it’s not non-existent,” said U of T’s Dr. Martha Brown, an associate professor in microbiology. “Should we all go out and be worried about it? There are probably more important things to worry about.

“It’s a probability game. It’s the probability of you being in the vicinity of mosquitoes that are carrying it [West Nile Virus] and then them coming and biting you.”

Dr. Colin D’Cunha, the Ontario Chief Medical Officer of Health, agreed. In a recent press release, he stressed that 99 per cent of those infected with the virus would not be affected or display symptoms. In comparison with the flu virus, which “kills 2,000 Canadians a year,” the risk of West Nile is minimal.

The West Nile virus presents symptoms similar to the flu, like fever, aches and occasionally rashes. In most cases the symptoms disappear within a few days.

In rare cases, the symptoms can include neck stiffness, high fevers and comas, as the virus spreads to the tissues of the spinal cord or brain, causing meningitis or encephalitis. The disease mostly affects the elderly and people with weakened immune systems.

The most common form of transmission is through the saliva of an infected mosquito, and the virus can’t be transmitted through normal interaction with an infected person.

Why all the fuss?

Since the risks of West Nile are minimal, the question might be raised: why is there so much worry?

Part of the reason may be since the West Nile virus is so new, vaccines and treatments for it have yet to be developed. The best way right now to fight the West Nile virus is by prevention.

The real cause for concern lies in the fact that not only has the West Nile virus spread to this continent, this year it emerged earlier in the season, exposing humans and animals to risk for a longer period of time. The spread of the virus has grown vigorously this past year, and some experts fear that a “periodic epidemic” will arise, claiming an increasing number of victims each year.