About the virus

West Nile virus (WNv) is mainly an infection of birds that is spread to humans and other animals by the bite of an infected mosquito. Mosquitoes become carriers of this virus by taking a blood meal from an infected bird.

Testing has shown that very few mosquitoes actually carry the virus and there is no evidence of people catching WNv from an infected person or animal through regular contact. Illness from WNv is more common in horses but it can also affect a small number of people.

Whereas nearly all people bitten by an infected mosquito build natural resistance to WNv and remain healthy, a small number may experience flu-like symptoms. In rare cases a person can develop an infection of the central nervous system that can lead to paralysis or death.

Precautions You Can Take

Personal protection

The goal of Edmonton's mosquito control program is to reduce biting by nuisance mosquitoes through targeting the larval stage. This also reduces the need for citizens to use chemical control on their property.

While an organized control program can provide some protection by reducing mosquito biting, it does not fully eliminate the risk of people contracting WNv .

  • You can avoid mosquito bites by staying inside at dawn and dusk when mosquitoes are most active.
  • To prevent them entering the home, ensure window and door screens fit tightly and are in good repair.
  • Keep grass mowed around your property to reduce shady resting sites for adult mosquitoes.
  • When outdoors, wearing light-coloured, long-sleeved tops and long pants will help.
  • One of the most effective ways to protect yourself from mosquito bites is to wear a mosquito repellent containing DEET. Recommendations for the strength of DEET repellents vary according to age.
  • For adults, concentrations up to 30% DEET are recommended. A limit of 10% DEET is suggested for children 6 months to 12 years of age, but DEET is not recommended for children under 6 months old. Instead, consider protecting babies from mosquito bites using mosquito netting.

Habitat reduction

Mosquitoes can develop in even small amounts of water allowed to stand for several days. You can reduce standing water around your home by cleaning eavestroughs regularly so water does not collect there and by ensuring your yard is free of old tires, unused buckets and other debris that can hold rainwater. You can also prevent mosquitoes from developing by covering rain barrels.

Horse vaccination

Many horses have died from West Nile virus (WNv). A vaccine for horses is available through local veterinarians.

The risk of people becoming seriously ill from the WNv is very low. Most mosquitoes are not infected and the majority of people bitten by an infected mosquito will show no symptoms or a very mild illness.

Did you know?

West Nile virus arrived in Edmonton in 2003.