U.S. CDC is studying whether bird flue is evolving to better infect mammals.

H5N1 bird flu is evolving to better infect mammals, CDC study suggests Rising H5N1 bird flu cases in the U.S. prompted the CDC to study the virus in ferrets, revealing it may have the potential to spread and cause severe symptoms in other mammals. Kamal Nahas Live Science

...

H5N1 has been detected in at least 46 people in the U.S. this year, causing only mild illnesses so far. The CDC maintains that the virus still poses little risk to the general public, but as a precaution, scientists have explored whether the avian virus has adapted to infect mammals.

H5N1 has been detected in about 50 mammal species, including cattle. The question is how adept the avian virus is at infecting mammals, and how easily it can spread when it jumps into a new species, like humans. In the ongoing outbreak, researchers haven't found any examples of human-to-human transmission, but they're watching out for signs.