Halting the Bird Flu Outbreak in Cows May Require Thinking Beyond Milk
The New York Times
A new study paints a complex picture of the outbreak, suggesting that the virus could be spreading in multiple ways and that it is not always mild in cows.
As the bird flu outbreak in dairy cows has ballooned, officials have provided repeated reassurances: The virus typically causes mild illness in cows, they have said, and because it spreads primarily through milk, it can be curbed by taking extra precautions when moving cows and equipment.
A new study, published in Nature on Tuesday, presents a more complex picture.
Some farms have reported a significant spike in cow deaths, according to the paper, which investigated outbreaks on nine farms in four states. The virus, known as H5N1, was also present in more than 20 percent of nasal swabs collected from cows. And it spread widely to other species, infecting cats, raccoons and wild birds, which may have transported the virus to new locations.
“There’s probably multiple pathways of spread and dissemination of this virus,” said Diego Diel, a virologist at Cornell University and an author of the study. “I think it will be really difficult to control it at this point.”
The outbreak, which officials first announced in March, has spread to at least 170 dairy farms in 13 states, according to the Department of Agriculture. It has also jumped into poultry farms and infected at least 10 farmworkers exposed to infected cows or poultry.
The exact origins of the outbreak remain unknown, but scientists believe that the version of H5N1 that is now circulating in dairy herds probably jumped into cows just once, most likely in late 2023 in the Texas Panhandle.
