At least 14 cats in the United States have died of H5N1 bird flu since the virus was confirmed in dairy cows in late March. The real number of infected cats is believed to be higher due to limited testing.

Earlier this month, officials confirmed that a domestic cat in Montana was also infected with H5N1 after exhibiting “neurologic signs” and the discovery of a dead skunk on the property. It’s unclear if the skunk was also infected.

The global spread of H5N1 clade – and the recent spread to a growing number of mammals – has raised concern about the possibility of human-to-human transmission from a future variant though, so far, only a few human cases have been found after contact with infected birds or cattle.

The U.S. Department of Agriculture (USDA) announced in late March that bird flu had been found in dairy cows in Kansas and Texas, making those the first-ever cases in cattle. The number of outbreaks at dairy farms has since risen to 51 in 9 states and a farm worker in Texas also tested positive.

On Tuesday, the CDC asked state health departments to continue influenza surveillance at enhanced levels throughout the summer to help detect potential cases of bird flu in the community. More samples will also be submitted for subtyping to help distinguish between seasonal flu and H5N1. {read}