Does the First U.S. Death Mean Bird Flu Is Getting More Dangerous?

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

Could this person’s deadly infection signal that the H5N1 virus is becoming more adept at infecting people and causing severe disease in humans?

Here’s what experts say.