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 past human flu exposure may provide some immunity to H5N1.

An H5N1 infection can be fatal for domestic animals, but there are steps you can take to minimize the risk of them catching the virus.