Avian flu typically spreads between wild and domestic birds but can spread to other animals and people. There have now been more than 40 confirmed human cases in the United States, according to the Centre for Disease Control,

So far this year, 18 countries have registered a total of 278 HPAI outbreaks in poultry. This is according to the Animal Disease Information System by the European Commission (EC; as of November 6). It monitors listed animal diseases in European Union member states and adjacent countries, but not Great Britain.

Initial testing had indicated the teenager’s infection was from bird flu and was confirmed in further testing, the Public Health Agency of Canada said in a statement. The teen has been hospitalized in Vancouver since Friday and was reported in critical condition on Tuesday.

Experts and health authorities say that while the risk of human infection with the H5N1 strain of avian influenza remains low, people should avoid contact with sick or dead birds.

Amid an ongoing outbreak of bird flu in American dairy herds and poultry flocks, Canadian officials have announced that a teen in British Columbia has been hospitalized in critical condition with what is believed to be bird flu.

Cases of H5N1 bird flu in U.S. dairy and poultry workers have largely been mild. However, a new case in a British Columbia teenager has experts worried.

A teenager has been left in critical condition after contracting the first presumptive human case of avian influenza in Canada. Expert Sam Scarpino discusses the health risk and potential for spread.