Companion animals and H5N1: What vets and pet parents should know

Companion animals, particularly cats, are no longer a side note in the U.S. H5N1 outbreak. Over the past year, federal agencies, local health departments, and veterinary experts have increasingly pointed to cats as a susceptible species, with severe disease and death documented after exposure to infected birds, dairy environments, raw milk, and some raw pet food products. CDC’s current pet guidance says most U.S. feline infections have been associated with H5N1-affected farms, while some others have been linked to commercially produced raw pet food and unpasteurized milk. AVMA reporting adds useful scale: nearly 70 domestic cat infections were documented by USDA in 2025 alone, and roughly 200 U.S. cat cases have been reported since the virus appeared in the country at the end of 2021. (cdc.gov)

That shift reflects how the outbreak has evolved since H5N1 was identified in U.S. dairy cattle in March 2024. A 2024 paper in Emerging Infectious Diseases described H5N1 infection in dairy cattle and reported high mortality among farm cats that consumed raw colostrum and milk from affected cows. Since then, agencies have documented additional household-cat exposures outside farm settings, expanding concern from barn cats and rural biosecurity to companion-animal practice and client education. AVMA experts have also noted that risk continues to rise and fall with avian migration patterns, with renewed infections and deaths in poultry and mammals after a lull in summer and early fall. (wwwnc.cdc.gov)

The clearest recent change has been the growing evidence around foodborne exposure. FDA says H5N1 can be transmitted to cats and dogs when they consume infected poultry- or cattle-derived products, including uncooked meat, unpasteurized milk, or unpasteurized eggs, if those ingredients have not undergone an inactivating step such as cooking, canning, or pasteurization. On that basis, FDA said manufacturers subject to the Preventive Controls for Animal Food rule and using such ingredients must reanalyze their food safety plans to account for H5N1 as a foreseeable hazard. That regulatory move followed a series of cat illnesses and recalls tied to raw products, including FDA’s notice about H5N1 contamination in certain lots of RAWR Raw Cat Food Chicken Eats and AVMA’s recall alert on Savage Cat Food Chicken boxes issued March 15, 2025. AVMA coverage has also underscored a practical challenge for clinics and clients: contaminated raw chicken diets linked to cat deaths in San Francisco and Los Angeles were associated with genotype B3.13, and some products had sell-by dates extending to September 2026, suggesting the virus may persist for long periods in frozen or refrigerated raw diets. (fda.gov)

The clinical picture for veterinarians is also becoming clearer. CDC says signs of bird flu illness in pets can include fever, fatigue, reduced appetite, inflamed eyes, ocular and nasal discharge, difficulty breathing, tremors, seizures, incoordination, and blindness. The agency also warns that indoor-only cats can still be infected, likely through contact with infected people, animals, or contaminated surfaces such as clothing. That’s important for history-taking: a pet parent may report no outdoor access and still have a meaningful exposure through raw feeding practices, contact with backyard poultry, farm visits, contaminated work clothes, or predation on infected wildlife or small mammals. AVMA experts specifically noted that ongoing H5N1 activity in wild birds and mammals such as house mice means cats remain at risk through hunting as well as diet. (cdc.gov)

Published case reports have reinforced those concerns. In an August 2025 Emerging Infectious Diseases report, investigators described four indoor-only cats in Southern California after exposure to recalled raw milk purchased in November 2024. Three cats consumed the milk; two died after a course consistent with H5N1, and a third tested positive, developed hind-limb paresis and blindness, received supportive care including oseltamivir, and recovered. The cat that did not drink the raw milk remained healthy and seronegative. The authors concluded that the report highlighted the risk raw dairy products pose to animal and human health, and said veterinarians should consider H5N1 in cats with acute neurologic signs and a history of exposure to wild birds or raw poultry or dairy products. (wwwnc.cdc.gov)

Public health agencies have echoed that warning. New York City’s health department said on March 14, 2025 that it was investigating two cats in separate households infected with bird flu and advised New Yorkers not to feed pets raw food or raw milk. CDC also notes a documented 2016 cat-to-human transmission event in New York City involving a veterinarian with prolonged, unprotected exposure to sick cats, underscoring why PPE and infection-control protocols matter in practice even though the overall public risk remains low. (nyc.gov)

Why it matters: For veterinary professionals, this story is less about rare spillover and more about a changing risk profile in everyday companion-animal medicine. Cats appear especially vulnerable to severe disease, and the exposure history now extends beyond obvious wildlife contact to commercial diet choices, household raw milk use, predation, and contaminated fomites. That means clinics may need to update triage questions, staff PPE protocols, isolation workflows, and client handouts. It also gives veterinarians a stronger evidence base for counseling pet parents against feeding raw meat diets or unpasteurized milk, particularly in households with cats or with people who have occupational exposure to poultry or dairy cattle. (cdc.gov)

What to watch: The next phase will likely center on surveillance and prevention: more testing of suspect companion-animal cases, additional pet food enforcement or recalls, and further refinement of guidance for veterinary teams handling exposed cats. USDA’s National Milk Testing Strategy and broader H5N1 response suggest animal-health surveillance will remain active, while FDA’s hazard determination signals continued scrutiny of raw and minimally processed pet foods. One practical implication from AVMA reporting is that recalled or contaminated frozen raw products may remain in homes for months because of long sell-by dates, so clinics may need to ask not just whether a client feeds raw, but whether older products are still stored or being used. For clinics, that means H5N1 is likely to remain a live client-communication and biosecurity issue through 2026. (aphis.usda.gov)