Highly Pathogenic Avian Influenza (HPAI) H5N1 in Raw Pet Foods and Milk: A Growing Threat to both Companion Animals and Human Health, and Potential Raw Pet Food Industry Liability.

The increasing popularity of raw meat-based diets (RMBDs) and raw milk feeding in companion animals presents a growing concern for zoonotic disease transmission. Recent evidence has demonstrated that these products can serve as vehicles for highly pathogenic avian influenza (HPAI) H5N1, an emergent viral threat with a host range from birds, dairy cattle, and pets to humans. Since the emergence of clade 2.3.4.4b in 2020, HPAI H5N1 has caused widespread outbreaks in poultry, wild birds, and mammals, including dairy cattle and cats. Transmission to pets has been linked to ingestion of contaminated raw pet food and unpasteurized milk. Notably, multiple outbreaks in cats across Europe, Asia, and North America have been associated with raw pet food products, while recent U.S. cases confirm direct viral transmission from infected pet food, raw milk, and colostrum. Experimental studies have also supported the plausibility of gastrointestinal and respiratory routes of infection in cats and dogs, with felines appearing particularly susceptible, often exhibiting severe clinical disease and high mortality. A number of documented recalls of H5N1-contaminated raw pet food and raw milk in the US underscore the persistence of infectious viruses in cold-stored food products and highlight the risks of feeding raw diets. Although pet-to-human transmission of the HPAI H5N1 virus has not been reported yet, cat-to-human transmission of the H7N2 influenza virus has been reported in the USA. This review presents current evidence on H5N1 in RMBDs and raw milk, its epidemiology in companion animals, outbreaks, and the health implications among pets and humans. By raising awareness among pet owners, industry stakeholders, and veterinarians, this paper highlights the immediate need for stringent surveillance and improved biosecurity in raw food supply chains to minimize viral transmission risks thereby safeguarding pet health and curb the potential spillover to humans.