Avian influenza (bird flu) is impacting wild birds worldwide and causing outbreaks in U.S. poultry and dairy cows, with human cases mainly reported in dairy and poultry workers. Presumptive positives have been reported in Marshall and Tama counties.

Any time a person catches H5N1, or bird flu, their infection is a chance for the virus to mutate in the wrong direction. When someone dies from the bird flu—as an elderly Louisiana man did on Jan. 6,

The U.S. has experienced its first death from H5N1 bird flu. Here’s what happened, plus how concerned you should be, according to doctors.

The death comes at a time when the H5N1 virus has recently undergone an unusual mutation that is causing concern to the World Health Organization.