Avian flu is rampant in poultry farms and in wild birds in the U.S. Every mutation brings the virus one step closer to the brink of human-to-human transmission, but predicting whether a virus will cross that threshold remains an uncertain science.

A highly infectious strain of avian influenza, or "bird flu," has led to a steep incline in egg prices around the country.

Bird flu outbreaks at multiple poultry farms across Japan from the end of 2024 to the beginning of this year are raising concerns over a possible repe･･･