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.

A Canadian teenager infected with bird flu — that country’s first case involving a locally acquired infection — is in critical condition and experiencing difficulty breathing, health officials said Tuesday.

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.

British Columbia health officer Dr. Bonnie Henry shared in a news conference that a teenager, who contracted the first presumptive case of bird flu in Canada, was in critical condition after developing 'acute respiratory distress.

Initial testing had indicated the teenager’s infection was from bird flu and was confirmed in further testing, the Public Health Agency of Canada said in a statement. The teen has been hospitalized in Vancouver since Friday and was reported in critical condition on Tuesday.

Cases of H5N1 bird flu in U.S. dairy and poultry workers have largely been mild. However, a new case in a British Columbia teenager has experts worried.