Another cause for concern: flu season is underway in the U.S., and as seasonal influenza virus goes around, “humans, ourselves, could be a mixing vessel,” Davis says. If a person were simultaneously infected with bird flu and seasonal flu, the two viruses could theoretically combine to create a more transmissible strain.

Canadian health officials have confirmed bird flu in a British Columbia teen. The Public Health Agency of Canada said Wednesday that tests showed the virus involved was related to a bird flu outbreak in poultry in the province.

Health officials were struggling to answer a broader and potentially worrisome question: how the infection occurred.

A Canadian teenager is hospitalized in critical condition with suspected bird flu, health officials reported 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.

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.

A Canadian teen is hospitalized in critical condition with what is believed to be bird flu, a British Columbia health official said Tuesday. It’s not clear how the teenager picked up the virus, which has been detected recently in wild birds and poultry in the province,

A Canadian teen is severely ill with what is believed to be bird flu. The teen is not known to have had any contact with infected animals.

A Canadian teenager is hospitalized in critical condition with a case of H5N1 bird flu, according to health officials. The Public Health Agency of Canada confirmed in a press release that the teenager in British Columbia,