Cases of H5N1 highly pathogenic avian influenza (HPAI) in domestic cats tapered off after this spring, until a case in early September led to the euthanasia of a pet cat. HPAI infection risks may return as birds migrate for the winter. Beyond the danger to pets, HPAI infections in companion animals increase the potential for the virus to jump species and become a human health risk.
“Any perceived benefit to a raw food diet is vastly outweighed by the serious risk of infection during this time.”
“The only certainty with influenza viruses is that they will evolve,” Kay Russo, DVM, partner, RSM Consulting, told Petfood Industry. “The more opportunities H5N1 has to infect humans, the greater the risk it could adapt for sustained human-to-human transmission…
“We often share our homes with our pets; this creates a potential bridge for the virus to jump to humans. Feeding pets a raw diet that may be contaminated with H5 virus could unintentionally expose both the pet and pet owners to serious risk…. So far, most of the human cases of H5 in the US have been relatively mild, but we have had a few hospitalizations and one death associated with the virus since the start of this outbreak.”
The potential for HPAI to spread among livestock, pets and humans may increase as autumn approaches.
Bird migrations and HPAI risk to pet cats
Bird migrations in winter and spring spread the virus among poultry and cattle. Migratory waterfowl, such as ducks and geese, serve as natural reservoirs for avian influenza viruses, often carrying the virus long distances while showing no signs of illness. During migration, these birds shed the virus through their secretions and feces, contaminating shared water sources, fields and other agricultural areas. Seasonal migration patterns and flyways act as a vector network, introducing and amplifying HPAI risks across species and regions. Once infected, poultry and cattle can then spread the virus in their meat, milk and other products.
“Cats in particular are very susceptible to the H5 virus,” Russo said. “Raw diets include milk or meat that have not undergone a ‘kill step’ for pathogens…”
“As the H5 virus continues to circulate in food-producing species like cattle and poultry, there is a risk to pets that are fed raw diets.”
History of HPAI infections in cats
In late 2024, a series of cat illnesses and deaths related to raw pet foods and unpasteurized milk drew public and federal attention to cases of highly pathogenic avian influenza (HPAI) in domestic cats. In Los Angeles County, public health officials confirmed seven cases of H5 bird flu in cats and warned that more cases likely went undetected. In Oregon, a cat caught the HPAI virus and subsequently died after eating raw frozen turkey pet food. Subsequently, FDA officials advised dog and cat food manufacturers to reanalyze their food safety plans to include HPAI virus when using uncooked or unpasteurized materials derived from poultry or cattle.
“These cat infections have highlighted a gap in our testing procedures for the H5 virus,” she said. “Current testing protocols are neither consistent or timely enough to detect all cases before milk or animals reach the processing plant.”
In February 2025, for the first time since cases were initially detected in domestic cats in 2022, a cat was confirmed as infected east of the Appalachian Mountains. That month, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service confirmed 24 cases of bird flu affecting domestic cats in Washington, New Jersey, Colorado, California, Kansas, New Mexico, Montana and South Dakota.
The first recorded case of bird flu in a domestic cat in the U.S. occurred in Linn County, Oregon in December 2022. Since then, cases have occurred throughout the U.S. Until February, all of these HPAI infections in domestic cats had been west of the Appalachian Mountains. These cases corresponded to the Pacific, Central and Mississippi flyway routes used by migrating birds. The cases identified in February in New Jersey occurred in the Atlantic flyway.
Following these cases, there were few recorded. Then earlier this month, the Food and Drug Administration (FDA) confirmed H5N1 highly pathogenic avian influenza (HPAI) contamination in specific lots of RAWR Raw Cat Food Chicken Eats following the death of a cat that consumed the product. Whole genome sequencing indicates the virus strains detected in the animal and the contaminated pet food originated from a common source.
“These infections were associated with the consumption of raw milk or raw poultry products,” Russo said. “Thermal processing, such as pasteurization or cooking, is the number one way to prevent these infections and pet owners should be made aware of this. Any perceived benefit to a raw food diet is vastly outweighed by the serious risk of infection during this time.”
