Bird Flu Virus Is One Mutation Away from Binding More Efficiently to Human Cells Canada’s first human case of bird flu has left a teenager in critical condition as human infections continue to emerge in the western U.S.

With reports of the first human death from bird flu in the US, some Americans are feeling an uncomfortable flashback to the early days of Covid-19, when infectious disease experts were talking about a new virus that was sending people to the hospital with respiratory infections.