Could Cats Become a Vector for Bird Flu?

Domestic cats could provide an unexpected new route for the bird flu virus H5N1 to evolve into a more dangerous form, according to a new study published on Monday.

In the year since the virus began circulating in dairy cattle, it has killed many cats, primarily on farms with affected herds. It has also sickened at least 60 people, most of whom had close contact with infected dairy cows or poultry.

So far, H5N1 does not spread easily among people, although studies have suggested that just one or two key mutations could allow the virus to make that leap.

There is no evidence that cats have spread H5N1 to people and they may not represent a major avenue for the evolution of bird flu, experts said. Still, if a cat were simultaneously infected with H5N1 and a seasonal flu virus, the H5N1 virus could potentially acquire the mutations it needed to spread efficiently among people.

The new study highlights the need for public health officials to ramp up bird flu surveillance in cats, which tend to have frequent contact with both wild animals and people, said Dr. Suresh Kuchipudi, a veterinary microbiologist at the University of Pittsburgh and an author of the paper.

For months, the testing of cows and people for H5N1 has been limited, leaving experts in the dark about the true scale of the dairy outbreak. Last week, the U.S. Department of Agriculture announced that it would begin testing the national milk supply to help identify infected herds.