A second type of bird flu has been found in U.S. dairy cows for the first time, the U.S. Department of Agriculture (USDA) announced on Wednesday.

Until recently, all dairy herds in the U.S. had been infected with a form of bird flu, or avian influenza, known as B3.13.

This version of bird flu, known as D1.1, has only ever previously been detected in wild birds and poultry, indicating that it has now spilled over into cows.

D1.1 has also been shown to be dangerous to humans. Of the 67 human cases of bird flu detected in the U.S. beginning in April 2024, one of the only patients infected with D1.1, was in Louisiana.

The Louisiana patient died earlier this year, although health officials said the patient was over age 65 and had underlying health conditions.

This is a developing story. Please check back for updates.