Answers to some common questions about the West Nile Virus
What is West Nile virus?
West Nile virus is a bird-borne infection spread by mosquitoes that was first isolated in
Africa in 1937. The first known incidence of the virus in humans in North America was in 1999.
In that year, there were 61 confirmed cases in New York City. By 2000, evidence of the virus
was found in birds throughout New York State and parts of neighbouring states. The rapid spread
of the virus has led to expectations that the virus could soon be found in birds in Ontario.
The virus is transmitted to humans by mosquitoes that bite an infected bird and then an
What are the symptoms?
In humans, most infections of the virus result in no symptoms. In a small number of cases,
flu-like symptoms such as fever, frontal headache, muscle aches, and, occasionally, skin rash
The time between infection and the onset of symptoms, called the incubation period, is
between three and 15 days. Most people infected with the virus show no symptoms at all. To
these people, the virus is harmless.
In a very small number of people, particularly the elderly and those with weakened immune
systems, additional symptoms such as neck stiffness, muscle weakness, stupor, disorientation
and coma can occur. Rarely, the disease can be fatal.
How serious is West Nile virus infection?
The virus is harmless to most people. Some people may develop flu-like symptoms such as fever,
frontal headache and muscle weakness or aches. Occasionally, a skin rash may appear. In a few
people, particularly the elderly and those with weakened immune systems, additional symptoms
such as neck stiffness, muscle weakness, stupor, disorientation and coma may occur. Rarely, the
disease can be fatal.
What Can I Do?
How can I reduce the chances of being bitten? You can reduce
your exposure to mosquito bites by wearing long sleeved shirts and long pants when outdoors and
by applying mosquito repellent. Mosquitoes breed in standing water. You can help to minimize
the mosquito breeding grounds around your home by:
- Recycling/disposing of unwanted containers
- Draining water regularly from rain barrels, flower pots, window boxes, planters and
swimming pool covers
- Making sure your eaves troughs drain properly
- Changing the water in bird baths at least once a week
- Drilling holes in the bottom of recycling bins, trash containers and children's tire
- Removing and recycling old tires, plastic containers and paint cans
- Turning over wheelbarrows, canoes and plastic wading pools to drain the standing water
What is being done about West Nile Virus?
The Region of Peel works with the City of Mississauga and other surrounding
municipalities and develops "West Nile Prevention Plans". These plans
include public information material being created and distributed, monitoring and
Where can I get more information?
For more information on mosquito control, how to protect yourself from mosquito bites and the
West Nile Virus visit
www.peelregion.ca/health/westnile or call Health Line Peel at 905-799-7700