Avian flu has infected dairy cows in more than a dozen states – a microbiologist explains how the virus is spreading

Although H5N1 typically infects wild birds, the virus has spilled over into domesticated animal populations, like dairy cows. Peter Cade/Stone via Getty Images

The current strain of avian flu, H5N1, is responsible for the culling of millions of domestic birds and has sickened more than a dozen farmworkers in 2024, most recently in Colorado.

The Conversation U.S. asked immunologist and microbiologist Jenna Guthmiller from the University of Colorado Anschutz Medical Campus to explain the historical roots of H5N1, its mode of transmission and how to avoid coming into contact with it.