# Tuesday, August 28, 2007

West Nile Virus

Cases of West Nile virus have risen throughout the western provinces. Currently 213 cases have been reported in Manitoba, which is double the amount of infection for all of Canada last year. Peak exposure to West Nile usually occurs between late July to mid August, with more cases expected to be reported since incubation time for the virus is usually 3 weeks. While it is currently not an epidemic, some experts are warning that the worst is yet to come.

West Nile virus is transmitted to humans when they are bitten by infected mosquitoes, which have previously fed on infected birds. Weather conditions can also play a large role in this virus, as mosquitoes prefer hot humid weather for breeding. As the first reported case of West Nile occurred in 2002, researchers are still uncertain about the long-term effects of this virus, but studies are showing that prolonged health concerns do occur.  This includes long term physical effects such as muscle weakness, paralysis, fatigue, headaches, confusion, depression, problems with concentration and/or memory loss. Therefore, it is important to recognize the symptoms of WN and obtain treatment accordingly.

Many people are bitten by infected mosquitoes and show no symptoms, and/or do not become severely ill. Illness usually occurs between 2 and 15 days of become infected, and generally causes flu-like symptoms. Mild cases of WN usually involve fever, headache and muscle ache, as well as swollen lymph glands and a rash. People who are otherwise in good health generally make a full recovery with no prolonged health problems.

For people who have weaker immune systems, including the elderly, WN can pose serious health risks, and can possibly be fatal. For these people, WN can lead to meningitis (inflammation of the spinal cord or lining of the brain) and/or encephalitis (inflammation of the brain). For these severe cases, the symptoms include the sudden onset of severe headaches, high fever, stiff neck, muscle weakness, vomiting, drowsiness, confusion, loss of consciousness, and paralysis. Medical treatment should be sought immediately if you have experienced a mosquito bite and are experiencing these symptoms. West Nile virus can cause these extreme symptoms in people of every age bracket and health status.

It is important during the season to pay attention to your local news or local health agency to be informed if any WN cases have been confirmed in your area. As WN can quickly spread to different regions via  birds, it is important to minimize your risk of being bitten. Some helpful tips for reducing your exposure are:

• Try to avoid being outside at dawn and/or dusk, as this is the period when mosquitoes are most active

• Wear long sleeved shirts and long pants when outside, as well as a hat; this will deter bites

• When going outside, use insect repellent. If you are planning on being outside for a long period of time, make sure you re-apply the repellant if needed

• Make sure your windows are properly fitted with screens so mosquitoes cannot enter your house. Do not leave your doors open.

• Mosquitoes need standing pools of water to breed. Make sure you remove standing water from such places as birdbaths, pool covers, flower pots, pet bowls and wading pools. You can also clean your eaves troughs in order to prevent clogs that can trap water.

• Report any dead birds to your local health agency, as testing can be done to determine if the bird is infected.

If you experience any of the mentioned symptoms, and have mosquito bites, see your family healthcare provider. As long-term effects of WN are not yet known, it is important to be aware of the virus, and to keep your physician informed. As the global climate changes, so does the habits and habitats of mosquitoes. This is also true for the birds that originally carry the virus. Check with local health agencies every summer for the latest data and information.

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