Nevada dairy cows have been infected with a new form of bird flu, the Department of Agriculture announced Wednesday.
The news signifies that the H5N1 virus has spilled from birds into cows at least twice.
“This is the first detection of this virus genotype in dairy cattle (all previous detections in dairy cattle have been HPAI H5N1 clade 2.3.4.4b, genotype B3.13). Genotype D1.1 represents the predominant genotype in the North American flyways this past fall and winter and has been identified in wild birds, mammals, and spillovers into domestic poultry,” the department said.
The findings were the result of state tracing and investigation.
“This is not what anyone wanted to see,” Louise Moncla, an evolutionary biologist who studies avian influenza at the University of Pennsylvania, told The New York Times. “We need to now consider the possibility that cows are more broadly susceptible to these viruses than we initially thought.”
Until now, all H5N1 detections have involved the B3.13 genotype, which has been linked to mild infections in dairy workers. The D1.1 genotype has also been implicated in human infections, including a death in a Louisiana resident over the age of 65.
The department has tracked 957 confirmed cases in cattle across 16 states.
“We shouldn’t be surprised about a new spillover to cattle, given the very significant activity in waterfowl across much of the United States,” University of Minnesota’s Dr. Michael Osterholm, told CIDRAP News.
This is a breaking news story. Please check back for updates.
