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 who is being treated in the critical care unit was confirmed to have been infected with the bird flu virus.

B.C. health officials say they still don't know how a teenager became infected with the H5N1 strain of avian flu, but say no further cases have been identified.Earlier this month, health officials announced they were investigating what was believed to be the first human case of H5N1 avian influenza caught in Canada.