West Nile virus – Transmission

How West Nile virus spreads

Almost all people infected with West Nile virus (WNV) contract it from the bite of an infected mosquito. A mosquito becomes infected when it feeds on the blood of a bird that is infected with the virus.

• About two weeks later, the mosquito becomes capable of passing the virus to people and animals by biting them.

In 2002, scientists discovered that people could be infected with West Nile virus in other ways, including blood transfusions and organ/tissue transplants.

• Find out how Canadian Blood Services is protecting the blood supply against WNv.

An infected mother can transfer the virus to her fetus. In addition, laboratory workers who handle infected specimens can get WNV through needle punctures or cuts.

There is no evidence to suggest that people can get WNV through contact with other people. Likewise, there is no evidence to date that the virus can pass from infected animals (horses, pets, etc.) to people.

image: Health Canada