House mice test positive for H5N1 bird flu

Nearly a dozen house mice in New Mexico have tested positive for H5N1 bird flu, according to federal officials, adding them to the growing list of mammals being infected with avian influenza.

The Animal and Plant Health Inspection Service at the U.S. Department of Agriculture reported Tuesday that 11 house mice in Roosevelt County in New Mexico had tested positive for the virus.

Detailed information about the cases were not immediately released but it’s the first time that bird flu has been found in the common house mouse in the real world. Mice had previously only been infected as part of lab experiments.

Tuesday’s report came just a week after alpacas in Idaho were also found to be infected with H5N1, and just over two months after the virus was found in dairy cows for the first time. The number of outbreaks at dairy farms in the U.S. has since risen to 81 in 9 states.

The global spread of H5N1 clade 2.3.4.4b – 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.

Three workers at dairy farms in Michigan and Texas have tested positive for H5N1 bird flu in recent weeks but only one of them experienced acute respiratory illness. More serious cases have been reported in other countries though none have involved human-to-human transmission.

Last month, the U.S. government announced nearly $200 million in funding to fight the spread of H5N1 bird flu in dairy cows, including support for dairy farms, testing, vaccine development, surveillance and measures to ensure the safety of commercial milk.