India, Feb. 6 -- A spillover of the second H5N1 avian flu genotype in dairy cattle has been confirmed by the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS).

Until now, all H5N1 detections in dairy cattle have involved highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b, genotype B3.13. This genotype is known for causing mild infections in dairy workers.

The B3.13 spillover from wild birds to dairy cattle was first reported in late 2023 or early 2024.

The B3.13 genotype has spread widely in cattle across the United States, infecting more than 900 herds in 16 states, as well as other animals, such as cats, skunks, and poultry.

Now, genotype D1.1, which is common in poultry and wild birds,...