Environmental Health & Prevention Services

What is West Nile Virus

West Nile virus is a virus spread by mosquitoes that can cause illness in humans. It was first identified in the province of West Nile, Uganda in 1937. West Nile virus activity has been found in Lambton County since 2001.

In 2012, there were two confirmed human cases of West Nile virus infection reported in Lambton County.

How is West Nile Spread?

West Nile virus is spread by the bite of an infected mosquito. Birds can carry the virus; mosquitoes bite the birds and become infected. However, not all mosquitoes are infected with the virus.

There is no evidence to suggests that West Nile virus can spread directly from person to person. There is also no evidence that the virus spreads directly from birds or animals to humans.

The virus can also be spread by:

• organ transplant
• blood transfusions
• breast-feeding
• mother to fetus

*These account for only a few cases.

Who Is At Risk

West Nile virus can affect people of any age and health. People with weakened immune systems and those over the age of 50 are at greater risk of developing serious illness from West Nile.

The Symptoms of West Nile Virus

Most people who get infected with West Nile virus do not get sick. For those who do become ill, symptoms occur 2-15 days after the bite of an infected mosquito. Symptoms can include mild fever, headache, swollen lymph nodes, skin rash and sore muscles.

In a few cases, the virus may cause swelling of the brain. This can result in the rapid onset of severe headache, muscle weakness, high fever, stiff neck and confusion. Long-term effects include tiredness, memory problems and depression.

West Nile Virus Protection

You can protect yourself and you family by reducing the changes of being bitten by mosquitoes.

• Apply and insect repellent containing DEET to clothing or skin. (Use a product that has not more than 30% for adults). Avoid eyes and mouth.
• Health Canada and the Canadian Pediatric Society advises that children aged 6 months to 2 years may receive 1 application per day of a product containing 10% DEET or less if chances of being bitten are high. Do not use DEET on children under 6 months of age.
• For children aged 2-12 years, use a product with 10% DEET or less. Do not apply to the face and hands, limit to less than 3 times a day.
• Take extra care when outdoors between dusk and early morning when mosquito activity is high.
• Wear long-sleeved shirts and pants when outdoors.
• Ensure door and window screens fit tightly and do not have holes.

Reduce Mosquito Populations

Mosquitoes require stagnant water to lay their eggs and mature before becoming biting adults. Reduce the amount of stagnant water on your property and you will lower the risk for mosquito breeding sites.

• Drain water from containers and toys that collect water, such as garbage cans, pool covers, flower pots, tires and tarps.
• Change water in wading pools, birdbaths, and pet bowls twice a week.
• Drain or drill holes in the bottom of containers so that water doesn’t collect.
• Keep roof eaves clear of debris.
• Fill low-lying areas that hold water.
• Maintain pools and aerate ornamental ponds or stock with fish.
• Do not let grass clippings enter roadside gutters or catch basins as these are perfect mosquito breeding sites.