Tests found bird flu in dairy milk from cows in Kansas and Texas on Monday, U.S. health officials said.
Type A H5N1 is known to infect birds and has sometimes infected people. Now it has surfaced in dairy cows in three states: Kansas, New Mexico and Texas.
Farmers in Texas first noticed dairy cows falling ill about three weeks ago. Now the virus appears to have reached about 10% of dairy cows in the affected herds. Unlike birds, cows generally recover from the virus after about a week.
There is no risk to the commercial milk supply or to the public, the U.S. Department of Agriculture said in a statement. Milk from sick cows is not being allowed onto the market.
The USDA also said it did not find any indication that the virus was changing to more easily infect people.
US reports its first case of bird flu in a domestic baby goat
The USDA reports that since the start of the outbreak in 2022, over 82 million birds and over 200 mammals in the U.S. have been impacted.
One week ago, goats in Minnesota who had been exposed to poultry infected with bird flu were themselves diagnosed with bird flu. It was the first time the disease had shown up in U.S. livestock.
Since mid-2022, outbreaks in U.S. poultry have grown to their highest level on record, prompting concerns over increased egg and meat prices.
Bird flu has shown up in dozens of mammal species, including in polar bears in early 2024.
The CDC says cases of bird flu in humans remain rare.