H5N1 bird flu found in alpacas for the first time

Alpacas at a small farm in Idaho have tested positive for H5N1 bird flu, according to state and federal officials, adding them to a growing list of mammals being infected with avian influenza.

The Animal and Plant Health Inspection Service at the U.S. Department of Agriculture reported Wednesday that four alpacas tested positive at a backyard poultry premises in Jerome County, Idaho.

The agency said the discovery was not entirely unexpected, citing the “high amount of virus in the environment” after infected poultry was culled at the site earlier this month and the co-mingling of multiple animal species.

“NVSL has confirmed that the viral genome sequence for these samples is the same sequence currently circulating in dairy cattle (B3.13), which is consistent with sequences from the depopulated poultry on this premises,” the agency said.

The U.S. Department of Agriculture (USDA) announced in late March that dairy cows had tested positive for bird flu, the first time the virus was ever found in cattle. The number of outbreaks at dairy farms has since risen to 68 in 9 states.

Unlike many other species, H5N1 is not causing significant mortality in cows as the virus is primarily concentrated in the udders. Tuesday’s announcement did not specify whether the alpacas died or exhibited any symptoms.

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.

Two workers at dairy farms in Michigan and Texas have tested positive for H5N1 bird flu in recent weeks, but in both cases they only experienced an eye infection and recovered quickly. More serious cases have been reported in other countries.

Earlier this 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.