Companion animals enter the H5N1 risk picture

H5N1 avian influenza is no longer confined to poultry barns and dairy headlines. For companion animal practice, the issue has moved into exam rooms, household risk assessments, and client education, as federal agencies, researchers, and the AVMA warn that cats, and in some situations dogs, can become infected through contaminated food, infected wildlife, livestock exposure, or contaminated materials brought home by people. (cdc.gov)

What changed over the past year is the strength of the evidence. The U.S. dairy cattle outbreak, first detected in March 2024, was followed by reports of illness and death in farm cats and then in indoor cats with no direct outdoor exposure. In a CDC report from Michigan, two indoor cats in dairy worker households developed respiratory and neurologic illness despite no known direct contact with infected farms, raising concern that contaminated clothing, footwear, milk residue, or other fomites may be enough to expose pets in some settings. AVMA reporting has also emphasized how quickly the epidemiology has shifted: USDA documented nearly 70 domestic cat infections in 2024 alone, and around 200 U.S. cat cases since the virus appeared in the country at the end of 2021. (cdc.gov)

Food exposure has become an especially important part of the story. CDC guidance now lists raw milk, raw or undercooked meat, commercially produced raw pet food, contact with infected birds or livestock, and contaminated objects as risk factors for animals. The FDA went a step further in January 2025, saying manufacturers covered by the Preventive Controls for Animal Food rule and using uncooked or unpasteurized poultry- or cattle-derived ingredients must reanalyze their food safety plans to include H5N1 as a known or reasonably foreseeable hazard. The agency said the move was driven by domestic cat illnesses and deaths associated with contaminated food products in multiple states. AVMA coverage added a practical detail that may matter for both recalls and client counseling: cats in San Francisco and Los Angeles died after eating a contaminated raw chicken diet, and the product carried a sell-by date extending into 2026, a reminder that virus in frozen or refrigerated raw diets may remain a risk long after purchase. (cdc.gov)

Recent case reports have sharpened the clinical picture. CDC notes that infected cats may show decreased appetite and energy, respiratory signs, neurologic signs, or die suddenly. An Emerging Infectious Diseases report described domestic cats infected after ingesting commercial raw milk in California in late November 2024, including one surviving cat from which H5N1 virus was isolated from urine, underscoring both the severity of feline disease and the diagnostic value of sample selection in live animals. The report concluded that veterinarians should include H5N1 on the differential list for cats with raw dairy or raw poultry exposure and acute neurologic disease. AVMA’s Veterinary Vertex discussion similarly stressed that ongoing circulation in wild birds and mammals such as house mice means predation remains a real route of exposure for cats, especially as cases rise again with avian migration patterns. (cdc.gov)

Industry and professional reaction has centered on surveillance gaps and risk communication. A March 2025 STAT commentary by veterinarians and One Health experts argued that companion animal surveillance remains limited and that H5N1 testing should be considered more routinely in cats with neurologic disease, especially because signs can overlap with other urgent differentials such as rabies. AVMA policy has also moved in a direction consistent with that concern, revising its stance on raw or undercooked animal-source protein diets and continuing to oppose raw milk for direct consumer sale because of infectious disease risk. (statnews.com)

Why it matters: For veterinary professionals, this is a biosecurity, diagnostic, and client-guidance issue all at once. Small animal teams may be the first to spot a household exposure tied to raw diets, backyard poultry, wildlife contact, or a family member working around dairy cattle. History-taking now matters more: diet, hunting behavior, bird exposure, livestock contact, household occupations, and whether contaminated work clothes or equipment enter the home can all change the risk assessment. Clinics also need clear PPE protocols and referral pathways for testing through state animal health and public health channels when H5N1 is suspected. The broader One Health lesson is familiar from other zoonotic pathogens too: as AVMA discussions around salmonellosis have highlighted, animal contact and contaminated shared environments can create transmission opportunities that are easy to underestimate if clinicians focus only on foodborne risk. (cdc.gov)

The message for pet parents is straightforward, even if the epidemiology is still evolving: don’t feed raw milk, don’t feed raw meat diets from poultry or cattle sources unless they’ve undergone a validated kill step, keep cats indoors when possible, prevent contact with sick or dead birds, and seek veterinary care quickly for sudden neurologic or respiratory illness. Cats remain the species of greatest concern in companion practice, but the broader lesson is that H5N1 is now a One Health problem at the household level, not just on farms or in wildlife. (fda.gov)

What to watch: The next phase will likely include more pet food oversight, additional state and federal guidance on testing and case handling, and closer attention to companion animal surveillance as regulators and clinicians try to understand how often household exposures are being missed. Seasonal increases tied to bird migration, plus the long shelf life of some frozen raw products, mean exposure investigations may continue to reach well beyond the obvious farm or outdoor-contact scenarios. (fda.gov)