Could the news that bird flu can spread from cows to humans be a worrying development?
For the first time a human has caught bird flu from a cow. Despite having no contact with birds, a dairy cow farm worker in Texas, America, started showing Avian flu symptoms in the eye, prompting the local health department to take samples, which proved to be positive for the variant (HPAI) A (H5N1).
The case has been published in the New England Journal of Medicine.
“It’s a huge thing that the virus has jumped from birds to mammals, dairy cows in this case, and then to humans,” says Steve Presley, the director of The Institute of Environmental and Human Health (TIEHH). “That’s why this paper in the New England Journal of Medicine is very significant. It’s going to lay the foundation, I believe, for a lot of research in the future of how the virus is evolving.”
This is the first case of the highly pathogenic avian influenza (HPAI) A (H5N1) transmitted from a mammal to a human, however it is not the first time the virus has spread to mammals.
Although it primarily affects birds, the virus has now spilt over into mammal populations as well – usually where a mammal has scavenged the carcass of a dead infected bird.
In January 2024 in Alaska, a polar bear became the fourth mammal to have been infected, following red foxes, a brown bear and a black bear. More widely, a variety of mammals have been infected, including otters, seals, mountain lions and raccoons.
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