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.

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

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. British Columbia health officials said Tuesday it’s not clear how the teen picked up the virus .

A Canadian teenager is hospitalized in critical condition with bird flu, health officials reported Tuesday. The teen has been receiving care at BC Children’s Hospital in Vancouver since Friday, the same day an initial test came back positive for H5 influenza.

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.