British Columbia health officials have yet to identify a likely source of the infection, though none of the teen's contacts have tested positive for the virus so far.

A teenager in British Columbia was hospitalized in critical condition with the disease, and officials were working to find out how the person was exposed to the virus.

Since Influenza A or flu viruses are named after the animal where they are most commonly found, avian viruses are naturally found in birds. H5N1 is a highly transmissible and usually mild disease in geese,