Health officials in British Columbia, Canada, have failed, for now, to confirm how a teenager there became infected with H5N1 bird flu.

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.

BC's top doctor Bonnie Henry says that a potential source of the exposure to the teen is a pet dog that was sick at the time the young person was infected.But she said all the testing that was done on the dog have come back negative for the virus.