A ny 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, becoming the first U.S. death from the disease—experts get especially concerned.

The death of a Louisiana resident who was over the age of 65 signals that future H5N1 infections are not guaranteed to be mild, health experts say

Bird flu is increasingly sparking concern across the country and in Illinois, following news this week of the first human death from the virus in the U.S., and of birds found throughout Illinois with suspected cases of the illness.