A new study suggests a culprit in bird flu's rapid spread through US cattle, and how to stop it

• Unpasteurized milk may be spreading the H5N1 bird flu between cows and to humans.
• A new study showed the virus can survive in raw milk on milking equipment for over an hour.
• Better cleaning of milking equipment and protective gear for workers could limit the virus's spread.

Contaminated milk may be spreading H5N1 bird flu between dairy cattle, contributing to a major outbreak across 12 US states. It may also be how humans are getting infected.