More than 80 domestic cats, among many other types of mammals, have been confirmed to have had bird flu since 2022 — generally barn cats that lived on dairy farms, as well as feral cats and pets that spend time outdoors and likely caught it by hunting diseased rodents or wild birds.

Until last week, all bird flu in dairy herds had been identified as the B3.13 variant, which was believed to have come from wild birds in late 2023 or early 2024. The USDA confirmed the virus's existence in the Nevada dairy cattle through milk sampling, the agency said.

Three of America’s top milk-producing states are not participating in the U.S. Department of Agriculture’s program designed to catch the spread of the virus.