Cows, cats and now alpacas: Bird flu discovered for first time in 4 Idaho alpacas

Four alpacas at a farm in Idaho were found to be infected with the H5N1 strain of Highly Pathogenic Avian Influenza, the Animal and Plant Health Inspection Service (APHIS) of the USDA said Tuesday.

Poultry infected with the bird flu were depopulated at the farm where the alpacas were infected earlier in May.

The APHIS noted that the infections were not unexpected due to the previous detection of bird flu at the site, the high amount of virus in the environment, and the mix of multiple species at the farm, although it was the first time the virus was found in alpacas.

The virus the alpacas were infected with was the same strain that has been spreading among dairy cattle across the US in recent months.

The H5N1 subvariant of bird flu has been increasingly reported in cattle in recent months, with 67 cases reported in nine states since March 25.

Additionally, on Tuesday, two dead cats were found to be infected with H5N1 in Curry County in New Mexico, according to data from the World Organisation of Animal Health. While dairy farms in the country have been affected by the bird flu, the location of the cats wasn't directly associated with a known outbreak on a dairy or poultry farm.

Virus found in beef tissue, milk

Last week, the USDA's Food Safety and Inspection Service (FSIS) announced that it had found viral particles in tissue samples, including from diaphragm muscle from one cow. Tissue samples from 95 other cows tested negative for the virus.

A study published last week in the New England Journal of Medicine last week found H5N1 in samples of milk from affected herds in New Mexico. The researchers fed mice the affected milk, all of which fell sick with the virus. High levels of the virus were found in the mice's respiratory organs and moderate levels were found in other organs.

The researchers also found that while heating affected milk to 145F for various amounts of time killed the virus, heating the milk to 161F for 15 or 20 seconds did not completely inactivate the virus.

Since 2021, Europe and the Americas have been suffering from a nearly continuous outbreak of H5N1 avian influenza, which has been described as "the largest-ever" on the three continents. The virus has affected tens of millions of birds and thousands of mammals worldwide. Outbreaks of the virus have also become more common in Africa and Asia in the past year and have even spread to Antarctica in recent months.

Two dairy farmworkers in the US have been infected with H5N1 in the past two months. Both suffered from conjunctivitis and recovered.

Health officials have expressed concerns that there may be more farm workers infected who aren't getting tested.