West Nile virus is a bird virus which is carried to humans by mosquitoes. It was first identified in the West Nile District of Uganda in 1937. Since then it has been found in Israel, Egypt, Romania, United States, Canada and Russia. It was present in North America in 1999, in New York and since then has spread to Canada.

80% of people infected with WNv show no symptoms and approximately 20% will show some mild flu-like symptoms. Less than 1% of people infected with WNv will show severe symptoms such as; meningitis (inflammation of the lining of the brain and spinal chord) and encephalitis (inflammation of the brain). Those who are at most risk are the elderly and those who have suppressed immune systems.

At present, the risk for WNv in the Thunder Bay area is low. However, the Thunder Bay District Health Unit is still participating in a surveillance program for the virus. Please see the dead bird collection program below.