A teenager in British Columbia has become the first person in Canada to test positive for the deadly H5N1 bird flu. Health authorities are urgently investigating how the virus spread, but they assure the public that the risk remains low.

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.

Based on current evidence, the risk of avian influenza infection for the public remains low. The risk of bird flu infection is higher for those who have unprotected exposure to infected animals, PHAC said.