New bird flu mutation found in dairy cows worries experts. The variant causes more severe human infections.

Dairy cows have contracted a new
variant of bird flu. (Unsplash photo)

Two people contracted severe bird flu infections from a new H5N1 variant known as D1.1. In one case, the man died; the other person is still in recovery. Experts are concerned about this variant emerging in cattle and what its severity might mean for livestock and humans, reports McKenzie Prillaman at ScienceNews.

“Cattle in Nevada tested positive for the H5N1 viral variant D1.1, which has been circulating in poultry and wild birds.” the Department of Agriculture announced Feb. 5. This recent discovery is the first detection of variant in dairy cattle.

Over the past year, about 1,000 cattle herds in 16 states have contracted H5N1 variant B3.13. Most people who were infected with this version of bird flu have been farmers working with livestock, according to the Centers for Disease Control and Prevention. There have been 67 cases in humans so far, with no known transmission between people. 

The emergence of the D1.1 variant poses additional health concerns for cows and people. “Another concern I have is that when we are looking at disease related to [B3.13], this has been by and large mild. But we have seen more severe human illness with the D1.1," according to veterinarian and environmental epidemiologist Meghan Davis of the Johns Hopkins Bloomberg School of Public Health. "I do worry that the clinical presentation in [dairy] workers and other people exposed to the dairy cows or their products could be different and potentially more severe,” 

Davis recommended more surveillance and biosecurity for farms to identify outbreaks among the cattle.