What is West Nile Virus?
West Nile Virus (WNV) is a virus found in wild birds and carried by mosquitoes. It was first identified in the province of West Nile, Uganda in 1937. Since then it has been identified in Egypt, Asia, Israel, South Africa, parts of Europe and Australia. In 1999, it was present in the United States for the first time, and in the summer of 2001 was discovered in birds in southern Ontario. In 2002 human cases were identified in Southern Ontario.
In 2002, within Leeds, Grenville and Lanark counties, five crows tested positive for WNV. During this period no mosquitoes were found to be positive for WNV.
How is West Nile Virus Spread?
- West Nile Virus is spread to humans through the bite of an infected mosquito.
- A mosquito becomes infected by biting a bird that carries the virus.
- You or your child cannot get West Nile virus from a person who has the disease.
- West Nile virus is not spread by person-to-person contact such as touching, kissing, or caring for someone who is infected.
- If illness were to occur, it would occur within 3 to 15 days of being bitten by an infected mosquito.
||Click on this picture for the WNV Transmission Cycle
Symptoms of West Nile Virus
Most people who are infected with the West Nile virus either have no symptoms or experience mild illness such as:
- body aches
- some persons may also develop mild rash or swollen lymph glands.
In some individuals, particularly the elderly, West Nile virus can cause disease that affects the brain tissue (encephalitis-inflammation of the brain or meningitis-inflammation of the lining of the brain and spinal cord). At its most serious, it can cause permanent neurological damage and can be fatal.
- the rapid onset of severe headache
- high fever
- stiff neck
- loss of consciousness (coma)
- muscle weakness
Is there a Treatment for the Virus?
There is no specific treatment for this virus, but the symptoms and complications of the disease can be treated.
- If you like to work in your garden, avoid early morning and evening when mosquitoes are most active
- Wear long-sleeved shirts, long pants and socks when outdoors during these active times
- Apply insect repellant to any exposed skin, sparingly
- Concentration of N,N-diethyl-m-toluamide (DEET) should be no greater than 30% for adults and no greater than 10% for children. Carefully read and follow manufacturer's directions for use
- Current labels on DEET-containing repellants state that they should not be applied to children under 2 years of age. Health Canada, however, recommends "DEET may be considered for children aged 6 months to 2 years, where there is a high risk of complications to the child from insect bites. Use sparingly, avoid the face and hands, apply only once a day, and use only the least concentrated product (10% or less)"
- Do not apply repellant to children's hands, or near any areas of mucous membrane such as the eyes or mouth
- Consider spraying clothing with repellants containing permethrin, as mosquitoes easily bite through thin clothing such as cotton t-shirts
- Special note when packing for camp: Check to see if aerosol sprays are allowed at your child's camp. If sprays are not allowed, make sure you pack an insect repellant that can be applied by pump or by hand
- Consider staying indoors from dusk to dawn when mosquitoes are most active. If you need to be outdoors during this period, cover up and use insect repellent for extra protection
If you experience any the following symptoms, you should see your doctor immediately:
- Extreme swelling or infection at the site of a mosquito bite
- High fever
- Muscle weakness
- Stiff neck
- Severe headaches
- Sudden sensitivity to light