H5N1 reaches companion animals, sharpening the focus for vets

Companion animals are moving closer to the center of the U.S. H5N1 response, with cats emerging as the clearest veterinary concern. Over the past year, federal agencies, state animal health officials, and veterinary public health teams have documented feline infections linked to raw milk, raw poultry-based diets, and probable indirect exposure from infected dairy operations. CDC now has dedicated guidance for veterinarians and animal care teams handling cats with suspected or confirmed H5N1, reflecting how the outbreak has expanded beyond poultry and livestock into small animal practice. (cdc.gov)

The backdrop is the broader multistate H5N1 outbreak that began affecting U.S. dairy cattle in 2024, on top of ongoing circulation in wild birds and poultry. Since then, spillover into mammals has widened, and USDA says its public mammal detections data now includes all known positive domestic cat detections, in part because of the heightened interest in cats during the dairy outbreak. That matters because cats appear more clinically vulnerable than dogs: FDA says cats can experience severe illness or death after eating contaminated uncooked poultry or cattle products, while dogs appear less affected and, as of that FDA update, had not been detected with H5N1 in the United States. (aphis.usda.gov)

Several developments pushed companion animal risk higher on the agenda. In December 2024, Oregon reported that an indoor cat died after consuming commercially prepared raw frozen pet food that tested positive for H5N1. In February 2025, Oregon and Washington officials warned pet parents after two cats in separate Multnomah County households were confirmed with H5N1 and had eaten the same raw pet food brand. FDA later posted additional notices involving contaminated raw cat food products, including certain lots of RAWR Raw Cat Food Chicken Eats, where whole genome sequencing suggested a common contamination source linked to a cat that became ill and was euthanized. FDA has also said manufacturers covered by the Preventive Controls for Animal Food rule and using uncooked or unpasteurized poultry or cattle ingredients must reanalyze their food safety plans to include H5N1 as a known or reasonably foreseeable hazard. (oregon.gov)

At the same time, the clinical picture for veterinarians has become clearer. CDC’s February 20, 2025, MMWR detailed two indoor domestic cats with confirmed H5N1 that lived in the homes of dairy workers and had no known direct farm exposure. Both had respiratory and neurologic illness, and the report said veterinarians in states with confirmed H5N1 in livestock should obtain household occupational information, test for influenza A viruses, wear PPE, and report suspected cases. The report also described monitoring of 24 potentially exposed veterinary staff members, underscoring that companion animal cases can become occupational health events for clinics as well as pet parents. (cdc.gov)

CDC’s more recent guidance for veterinarians and animal caretakers builds on that lesson. The agency says cats and other captive wild animals with suspected or confirmed H5N1 can present with signs ranging from mild illness to severe neurologic disease and rapid death, and it recommends precautions for veterinary teams working in close contact with these patients. CDC also continues to say the overall risk to the U.S. public is low, but people with close or prolonged unprotected exposure to infected animals or contaminated environments are at greater risk. For pet parents, state and federal agencies are now consistently warning against feeding raw meat diets, raw treats, or unpasteurized milk, and against allowing pets access to wild birds, poultry, or cattle. (cdc.gov)

Why it matters: For veterinary professionals, this changes case workups, client counseling, and clinic safety protocols. In cats with acute neurologic signs, severe respiratory disease, sudden death, or relevant food or farm exposure histories, H5N1 now belongs on the differential in affected regions. History-taking needs to cover raw diet use, raw milk exposure, hunting behavior, wildlife contact, backyard poultry, and whether anyone in the household works with dairy cattle or poultry. Clinics may also need clearer PPE, isolation, specimen handling, and reporting workflows, particularly in areas where H5N1 is circulating in livestock or birds. (cdc.gov)

There’s also a client communication challenge. Pet parents may still think of H5N1 as strictly a poultry issue, but the recent cat cases show how exposure pathways can be indirect, including contaminated food products and fomites brought home from farms. That creates an opening for veterinarians to give practical prevention advice: avoid raw or undercooked animal-source diets, avoid unpasteurized dairy products, keep cats indoors and away from wild birds, and contact a veterinarian promptly if a pet develops compatible signs after a possible exposure. Those recommendations align with guidance from CDC, FDA, AVMA-linked resources, and state animal health agencies. (oregon.gov)

What to watch: The next phase will likely include more surveillance in cats, more enforcement and oversight around raw pet food safety plans, and more detailed veterinary infection-control recommendations as agencies learn from additional companion animal cases and traceback investigations. (fda.gov)