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,

Canada's Public Health Agency has confirmed that a British Columbia teenager hospitalized last Friday is the country's first ever human case of domestically acquired avian flu.

A British Columbia teenager is in critical condition with Canada's first presumptive human case of avian influenza. Officials suspect the H5N1 strain, known to have low human transmission risk. Despite no known human-to-human spread,