Bird Flu Spreads to Dairy Cattle in Mountain West

H5N1 Virus Confirmed in Cattle Across Western States

Bird flu has recently spread to dairy cattle in the Mountain West, raising concerns among federal animal health officials. While the virus known as H5N1 has long impacted poultry flocks, its appearance in cows marks a troubling development, though it is not currently considered a threat to public health.

Recent outbreaks have affected poultry in several states, including Colorado, Montana, New Mexico, and Wyoming. Meanwhile, the virus has been confirmed in cattle in Arizona and Idaho. Additionally, a February case involving 20 non-poultry birds in Nevada was documented by the Centers for Disease Control and Prevention (CDC).

While highly lethal to poultry often killing entire flocks within days cattle appear more resilient, according to the CDC. Human infection cases are rare but do occur, typically in people with direct exposure to infected animals.

“The cases that we’ve seen so far have been people working with sick chickens or working with infected cattle and have large occupational exposures,” said Brian Labus, associate professor at the University of Nevada, Las Vegas. “So far we have seen 70 cases in the United States and one person has died. But we haven’t seen it spread person to person.”

A federal testing requirement was introduced last spring, mandating that cattle be screened before transport. Officials say this policy has helped limit the virus’s spread. The CDC is continuing to monitor H5N1 in humans using its existing flu surveillance systems.

Labus added that “processes such as milk pasteurization and proper cooking” help prevent transmission through dairy and meat products.