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.

The Canadian Food Inspection Agency (CFIA) has also been testing milk for signs of H5N1 in dairy cows. Canada has had no cases of H5N1 reported in dairy cattle. There's also no evidence of bird flu in samples of commercial milk. "Milk and milk products that have been pasteurized are safe to consume," the Public Health Agency of Canada said.