Bird Flu May Be Airborne on Dairy Farms

In unpublished research, researchers found live virus on equipment, in wastewater and in the air in milking parlours. In new study, scientists found live virus in the air of milking facilities, suggesting that cows and farmworkers might have become infected by inhaling the pathogen. The virus may also spread by water used to clean cattle barns or contaminated with discarded milk.

The study was posted online, and has not been peer reviewed for publication, but the results are consistent with those from other teams who found that contaminated milking equipment might not explain all cases of bird flu observed on farms. The study also found infected cows with no visible symptoms, suggesting that bird flu may spread from cows that appear healthy. 

H5N1 was first detected in dairy cows in March 2024. Since then, it has spread to more than 1,000 herds in 17 states, the majority of them in California, the nation’s leader in dairy production. Bird flu has also infected dozens of people, hospitalizing a few and killing one.