West Nile virus

Causes

How is West Nile virus spread?

West Nile virus is usually spread by the bite of a mosquito that has fed on an infected bird. In very rare cases West Nile virus can be spread through:

• blood transfusion
• organ or tissue transplants
• pregnancy (from mothers to unborn babies)
• breast milk
• exposure of laboratory workers to infected medical specimens

You cannot get West Nile virus by:

• donating blood
• touching or kissing a person with the virus
• touching nurses or others who care for someone with the virus

Canadian Blood Services and Héma-Québec routinely test blood donations in Canada for the presence of West Nile virus to avoid accidental infection through blood transfusion.