West Nile Virus (WNV) is spread to humans by the bite of an infected mosquito. Mosquitoes become infected by biting an infected bird. The virus is not spread by person-to-person contact. It cannot be spread directly from a bird to a human. In a very small amount of people, WNV has been spread through blood transfusions, organ transplants, breastfeeding, and from mother to child during pregnancy.
The risk of becoming seriously ill as a result of infection with WNV is low, and most people who become infected experience no symptoms or have a very mild illness.
Most mosquito bites cause itching and minor irritation. Symptoms of WNV usually appear within 2 to 14 days after being bitten. Some of the less serious symptoms are:
More serious symptoms are rare but can occur especially in older people and in people who are immunocompromised. If you have any of the following symptoms after being bitten by a mosquito, get medical attention immediately:
Extreme swelling or infection at the site of the mosquito bite is another reason to get medical attention.
Health Canada advises that DEET-containing repellents are not to be used on children under 6 months of age. DEET may be considered for children aged 6 months to 2 years if there is a high risk of infection if the child gets bitten. For these children apply once a day and use sparingly; avoid application to the face and hands. For children 2 to 12, apply DEET no more than three times a day and use the least concentrated product (10% DEET or less). For children older than 12 and adults, products containing no more than a 30% concentration of DEET will provide sufficient protection. Apply sparingly.
Mosquitoes can lay their eggs even in small amounts of standing water. It takes about four days for the eggs to grow into adults. Health Canada recommends:
If you have any questions, contact KFL&A Public Health at 613-549-1232.
Revised: 2012-10-10