Prevention hints from the U.S. Centers for Disease Control:

Avoid mosquito bites to avoid infection. To avoid mosquito bites:


1 Apply insect repellent containing DEET (N,N-diethyl-meta-toluamide) when you're outdoors.
2 When possible, wear longCsleeved clothes and long pants.
3 Consider staying indoors at dawn, dusk, and in the early evening, which are peak mosquito biting times.
4 Limit the number of places available for mosquitoes to lay their eggs by eliminating standing water sources from around your home.
Check to see if there is an organized mosquito control program in your area. If no program exists, work with your local government officials to establish one.

Health Canada advises:
Minimize your time outdoors at dawn and dusk when mosquitoes are most active and, whenever possible, wear long-sleeved tops and long pants when spending time outside.
Use an insect repellent containing 10 per cent or less DEET (N, NCdiethylCmethylCmetaCtoluamide) for children and no more than 30 per cent DEET for adults.
For children between six months and two years of age, use one application per day of a product containing 10 per cent or less DEET in situations where a high risk of complications due to insect bites exist
For children between two years and 12 years of age, up to three applications per day of a product containing 10 per cent or less DEET can be used.
Individuals 12 years of age and older can use a DEET products of up to 30% DEET concentration. More information on the safe use of insect repellents can be found on Health Canada's Web site.[url]http://www.hc-sc.gc.ca/pmra-arla/english/pdf/pnotes/deet-e.pdf[/url]
Make sure door and window screens fit tightly and are free of holes.

Take action to reduce mosquito breeding sites around your home, local parks and community. For more information see the Information Sheet entitled Effective Control of Mosquitoes Around Your Home on the Pest Management Regulatory Agency web site at:
[url]www.hc-sc.gc.ca/pmra-arla[/url]

Ensure that things in and around the yard like pool covers, saucers under flower pots, children's toys, pet bowls and wading pools are regularly emptied of standing water.
Clean eavestroughs of debris regularly so water does not accumulate.
Empty and clean bird baths twice weekly.
Ensure that openings in rain barrels are covered with mosquito screening or tightly sealed around the downspout.
Aerate ornamental ponds and stock with fish that eat mosquito larvae.
Old tires are one of the most common mosquito breeding sites. Ensure that your yard is free of debris, such as old tires, that can accumulate rainwater.

What are the symptoms?

Symptoms are usually mild and include fever, headache, body aches, sometimes skin rash and swollen lymph glands. Severe infection is marked by headache, high fever, neck stiffness, stupor, disorientation, with coma, tremors, convulsions, paralysis and occasionally death.

Anyone with those symptoms should seek medical attention as soon as possible.

There is no documented evidence that a pregnant woman or her fetus are at increased risk due to infection with West Nile virus.

If illness occurs, it usually happens within five to 15 days of being bitten by an infected mosquito.

How is it spread?

The Culex pipiens or common household mosquito spreads the virus when it feeds on a blood meal from infected birds. Scientists believe that the most likely "reservoir" for the virus in North America is the common sparrow, which can tolerate the infection. Among birds, the virus has had the greatest impact among crows. In 1999, in the New York area, the crow population crashed by about 90 per cent in a few months.

[url]http://www.cbc.ca/news/background/westnile/gfx/WestNilecycle1.gif[/url]
West Nile transmission cycle
Courtesy C.D.C.


Ten days to two weeks after the initial blood meal, the West Nile virus reaches the mosquito's salivary glands and can then be transmitted to birds, animals or humans. Since 1999, the virus has been found in wild birds, humans and horses across the United States and Canada.

There is no evidence that West Nile virus can be spread directly from human to human. Nor is there evidence that a human can contract the West Nile virus by handling infected birds. Scientists believe the human immune system prevents the virus from multiplying in large numbers. That prevents humans from transmitting the virus to mosquitoes.

[IMG]http://www.cbc.ca/news/background/westnile/gfx/canada.jpg[/IMG]


Province or territory Cases of West Nile virus
British Columbia Human cases: (probable and confirmed-- travel related): 18

Yukon Human Cases (probable, travel related) 1.
Northwest Territories No confirmed cases.

Nunavut No confirmed cases.

Alberta Human cases (confirmed): 252
Horses: (confirmed cases) 180
Birds (confirmed cases): 232
2002
Human cases: 2

Saskatchewan Human cases(probable and confirmed): 731
Deaths: 6 (West Nile "contributing factor")
Horses (confirmed cases): 143
Birds (confirmed cases): 162


Manitoba Human cases (probable and confirmed): 137
Deaths: 2
Horses (confirmed cases): 53
Birds (confirmed cases): 133


Ontario
Human cases (confirmed):83 (confirmed travel-related): 1
Note: There were two deaths in Ontario indirectly related to West Nile.
Horses (confirmed): 42
Birds (confirmed cases): 240
2002
Human deaths: 18
Human cases (probable and confirmed): 395


Quebec Human cases (probable): 17
Horses (confirmed cases): 8
Birds (confirmed cases): 836
2002
Human deaths: 2
Human cases (probable and confirmed): 19


New Brunswick Birds (confirmed cases): 6.

Newfoundland and Labrador No confirmed cases.

Nova Scotia Human cases (confirmed) 1 (travel related).
Horses (confirmed cases):1 Birds (confirimed cases): 12



Prince Edward Island No confirmed cases.

In 2003, there were 1,388 cases of West Nile, with 848 of those cases originating in Saskatchewan, where there were no cases the previous year.
In 2003, 14 people died from West Nile-related illnesses in Canada, 10 of them in Saskatchewan. Two deaths occurred in Manitoba and two in Ontario. In some cases, West Nile was listed as a secondary cause of death.
In 2002, Ontario had a total of 308 confirmed and 87 probable cases of West Nile; 18 people died. (One case was travel-related; four deaths are still under investigation).
In 2002, Quebec had 19 confirmed cases and two deaths from West Nile.
In 2002, Alberta had two travel-related cases of West Nile.
West Nile caused 284 deaths in the United States in 2002.
In 2000, 21 cases were reported in the United States, including two deaths in the New York City area.
In 1999, a strain said to be virtually identical to the Israeli strain was detected in New York City; 62 cases of severe disease, including six deaths, occurred in the New York area.
In 1957, the virus was blamed for the deaths of several elderly patients in Israel.