A genotype of highly pathogenic avian influenza previously identified in wild birds has been found for the first time in dairy cattle, the Agriculture Department said Wednesday.
Genotype D1.1, which the USDA’s Animal and Plant Health Inspection Service says has been the predominant genotype of the virus in North American flyways this past fall and winter, was confirmed in a herd of Nevada dairy cattle last Friday.
While dairy cattle likely derived the virus from birds when it was first detected in cattle early last year, this is the first time a jump between species has been confirmed, American Association of Bovine Practitioners executive director Fred Gingrich told Agri-Pulse Wednesday. A different genotype — B3.13 — has been found in all other dairy cattle cases to date, an indication that the virus was likely spreading from cow to cow.
It’s easy to be “in the know” about agriculture news from coast to coast! Sign up for a FREE month of Agri-Pulse news. Simply click here.
“This is the first time we’ve documented that the cows got it from wild birds,” Gingrich said, adding that it is “certainly concerning, because it would just be pretty damn hard for us to keep birds off of dairies."
The virus began spreading in the national dairy herd after cattle in Texas were shipped to other states in early 2024. "Whole genome sequencing analysis suggests an initial single spillover event of the virus from wild birds to dairy cattle, most likely occurring in the Texas panhandle in December 2023, with onward spread of the virus to eight other states," according to a USDA epidemiological analysis released in July.
The virus genotype was detected following silo testing under the agency’s National Milk Testing Strategy, which was put in place last December. Nevada is one of 28 states that signed on to the effort.
