How deadly is the bird flu? The US has reported its first death from avian influenza, H5N1. Here's what to know about bird flu mortality rate and who is at risk.

Two months shy of the fifth anniversary of COVID-19 being declared a global pandemic, the US has recorded its first human death as a result of avian influenza H5N1 infection. The unidentified Louisiana man contracted the virus through contact with infected wild and domestic birds on his property

The CDC on Thursday urged labs nationwide to determine within 24 hours of admission whether people hospitalized with the flu have seasonal influenza or are infected with the bird flu that's behind an escalating outbreak in dairy cows and poultry.

CDC officials say they extended the guidance now because they are seeing more H5N1 patients whose illness they cannot track back to an infected bird or cow.