A bird flu outbreak in a Wisconsin dairy cattle herd has raised questions about whether gain-of-function research at a nearby university laboratory may have played a role.
Last month, the US Dept. of Agriculture (USDA) identified what it described as the first known case of highly pathogenic bird flu in a dairy cattle herd in Dodge County, Wisconsin. The agency characterized the outbreak as a “spillover” event from wildlife to cattle.
The virus responsible for the outbreak was identified by two scientists at the University of Wisconsin–Madison School of Veterinary Medicine — Keith Poulsen, DVM, Ph.D., and Yoshihiro Kawaoka, DVM, Ph.D. Both scientists have published research on gain-of-function experiments involving bird flu viruses.
Kawaoka directs the university’s Influenza Research Institute, a lab known for conducting gain-of-function research on H5N1. The lab is located approximately 40 miles from the Dodge County outbreak site.
The university confirmed that both scientists are conducting H5N1 research but denied that the work constitutes gain-of-function experimentation. University officials said the research is intended to better understand bird flu strains circulating among wildlife and livestock.
The scientists identified the virus as the H5N1 clade 2.3.4.4b genotype D1.1 — a strain that contains mutations linked to increased transmissibility.
Karl Jablonowski, Ph.D., senior research scientist at Children’s Health Defense, said the outbreak is notable because national databases show no recent mammalian hosts of the D1.1 strain near Wisconsin.
Two isolated spillover events involving the same strain were identified earlier in Arizona and Nevada, though federal officials said the Wisconsin case is unrelated.
While federal agencies said bird flu currently poses a low risk to the general public, the World Health Organization reported that a 3-year-old girl in Mexico died in 2025 after contracting the D1.1 strain.
Recent scientific studies have suggested the D1.1 variant may be better adapted to infect mammals, including humans, than earlier strains.
Hellbound and Down 