Why has bird flu in the US spread to cows and what’s the risk for humans? Al Jazeera EnglishOpinion | H5N1 Already Killed Millions of Birds. Humans Share the Blame. The New York TimesLatest bird flu outbreak in cows hits dairy farm industry USA TODAYBird Flu Outbreak in Dairy Cows Is Widespread, Raising Public Health Concerns | Infectious Diseases | JAMA JAMA NetworkBird flu, pandemic risk, transparency, planning | News | Harvard T.H.