Very few humans have gone up against bird flu. But we've all dealt with seasonal flu for years. Some of our immune systems might be primed to fend off a worse case, research finds.

H7N9 — is detected in at a poultry farm; scientists learn that past human flu exposure may provide some immunity to H5N1.

Mississippi state and federal officials have confirmed an outbreak of a strain of bird flu not reported in the U.S. since 2017, with quarantine and depopulation efforts already underway. In a