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Pharmaceuticals2026-06-13 · 8 min read

Bird Flu (H5N1) in Cats and Dogs: What 2026 Outbreak Data Means for Owners

HPAI H5N1 bird flu has sickened and killed cats fed raw pet food and raw milk. Outbreak data and CDC reports explain cat susceptibility, dog risk, and when to call your vet.

Ran Chen
Ran Chen
Founder, VetMedGuide. Life-sciences operator and 10× global market-access lead.
Published

A cat in Grant County, Washington, tested positive for highly pathogenic avian influenza (HPAI) H5N1 in January 2026 and died. It was not an isolated event. Since the current outbreak began in 2022, 149 domestic cats in the United States have tested positive for bird flu, according to state and federal tracking, and clinicians describe mortality in infected cats as very high. A global outbreak that began in wild birds and poultry in 2020–2021 has now spilled into mammals — including companion animals — on multiple continents.

If you own cats, keep backyard poultry, or feed a raw diet, the question is no longer whether bird flu is circulating. It is. The questions are how a pet actually gets exposed, which animals are most at risk, how serious it is, and what to do if your cat or dog seems sick. Outbreak surveillance and the published case data give clear answers — and they point at a few specific, avoidable exposures.

Quick answer: who is at risk

HPAI H5N1 is widespread in wild birds and has caused large outbreaks in poultry and, since 2024, in U.S. dairy cattle. Cats are unusually susceptible: in published case series, most infected cats have died, often within about two days of the first signs. Dogs can be infected but generally have mild illness and low mortality. The single biggest, most preventable exposure for indoor pet cats is raw pet food, raw meat, and unpasteurized (raw) milk. Outdoor and barn cats are also exposed through wild birds and infected dairy herds.

The public-health risk remains low, but it is not zero. In a report published in May 2026, the CDC documented the first known infection of a person (a veterinary professional) linked to an infected domestic cat. Call your veterinarian promptly if a cat shows neurologic signs, severe lethargy, or breathing difficulty — especially after eating raw food or milk.

What the outbreak data show

A World Organisation for Animal Health (WOAH) WAHIS extract of reported animal outbreaks shows how much H5N1 is circulating. Across the records analyzed (run date 2026-06-09), there were roughly 2,500 reported HPAI outbreak events in animals — about 2,100 in non-poultry species including wild birds, and nearly 400 in poultry — with a steep rise into 2025: about 130 events recorded in 2024, over 1,700 in 2025, and more than 650 already recorded in 2026. Reported outbreaks span Europe, the Americas, and beyond. These figures are an extract of officially reported outbreaks, not an exhaustive global count, but they confirm sustained, widespread transmission.

In the United States, the dominant virus is H5N1 clade 2.3.4.4b. Since 2024 it has driven a multi-state outbreak in dairy cattle, which is the backdrop for much of the companion-animal exposure (see the FDA and CDC links in Sources). The FDA reissued guidance in September 2025 requiring cat and dog food manufacturers to treat H5N1 as a known hazard when using uncooked poultry or dairy ingredients.

Why cats are the companion-animal concern

Cats — domestic and wild felids alike — are strikingly sensitive to H5N1. A 2025 systematic review and meta-analysis of H5N1 in cats found a case-fatality rate of about 74%, with most deaths occurring within a median of two days after signs began. About 97% of affected cats showed clinical signs, most often lethargy, ataxia (loss of coordination), progressive neurologic deterioration, fever, and respiratory difficulty. Necropsies commonly found pneumonia, liver necrosis, and encephalitis — evidence that the virus disseminates systemically and reaches the brain.

Two patterns matter for owners. First, severe disease can progress from vague signs (not eating, quiet, fever) to neurologic compromise very quickly. Second, indoor-only cats have been infected, which is what makes the dietary route so important.

How cats and dogs actually get exposed

The CDC and FDA have identified the main routes:

  • Raw pet food and raw meat. Multiple H5N1 illnesses and deaths in indoor cats have been traced to commercially sold raw poultry-based diets. Recalls and investigations have linked contaminated product to sick cats in Oregon (a brand recalled in December 2024 after a cat died), New York City (March 2025), and San Francisco (an FDA alert in September 2025 named a specific raw cat food lot). In several cases, testing matched the virus in the food to the virus in the cat.
  • Unpasteurized (raw) milk. A cluster of 19 cats in Los Angeles County became ill in late 2024 through early 2025 after consuming commercially purchased raw milk, raw meat, or raw pet food; nine tested positive and most died or were euthanized. Raw milk from infected dairy cattle can carry infectious virus.
  • Wild birds and the environment. Outdoor, barn, and farm cats are exposed through sick or dead wild birds and their feces, and through contact with infected livestock.
  • People and fomites. Rarely, indoor cats with no known direct exposure have been infected, likely via contaminated clothing or surfaces brought home by people.

Dogs are less susceptible. The FDA notes that dogs can contract H5N1 but usually show mild signs and have low mortality compared with cats. Still, avoid feeding dogs raw poultry, raw eggs, or unpasteurized milk from affected animals.

Can my pet give me bird flu?

The general risk to the public remains low, and there is no evidence of sustained human-to-human spread. But transmission from a mammal to a person is now documented. In a CDC MMWR report (May 2026), a veterinary professional exposed to an infected domestic cat in Los Angeles County had blood-test evidence of prior H5N1 infection despite having had no flu-like symptoms. The cats in that cluster had consumed raw animal products.

The practical takeaway is the same one infection-control teams emphasize: treat a suspected H5N1 case in a cat with caution. Use gloves and a mask, isolate the animal from other pets, and do not handle sick or dead wild birds bare-handed. If you work with poultry or dairy and your cat becomes ill, tell your veterinarian that exposure history explicitly.

If you keep backyard poultry

Backyard flocks are squarely in the outbreak pathway because wild waterfowl introduce the virus. The CDC and USDA recommend tight biosecurity: keep feed and water away from wild birds, exclude wild waterfowl, dedicated clothing and footwear for the coop, and report sudden illness or die-offs to your state veterinarian or USDA. A fatal human H5N5 case in a backyard-flock owner in Washington (November 2025) underscores why this is taken seriously.

There is no H5N1 vaccine licensed for cats or dogs in the United States. Prevention is about limiting exposure, not immunizing the pet.

When to call your veterinarian

Seek veterinary care promptly — and mention bird flu and any raw-food or raw-milk exposure — if your cat or dog shows:

  • Sudden lethargy, hiding, or refusal to eat
  • Fever
  • Difficulty breathing, open-mouth breathing, or nasal discharge
  • Neurologic signs: incoordination, trembling, circling, tremors, or seizures
  • Sudden death of an outdoor cat, or of an indoor cat on a raw diet

Keep the pet isolated from other animals and people, and call ahead so the clinic can prepare. Tell the clinic about raw diets, raw milk, poultry or dairy farm contact, and any known wild-bird exposure. If a cat dies suddenly after consuming a raw product, save the packaging and lot information — public-health and FDA investigators use it to trace contaminated product, and your report may protect other pets.

The bottom line for pet owners

Bird flu is circulating widely, and cats are the companion animal most at risk — not from casual contact, but from specific, avoidable exposures led by raw pet food and raw milk. The largest single thing most indoor-cat owners can do is stop feeding uncooked poultry, meat, and unpasteurized dairy. For backyard-poultry keepers, biosecurity is the lever. Risk to humans is low but real, so handle sick animals with care and call your veterinarian early rather than waiting for neurologic signs to develop.

Sources

Topics
Vaccination & Infectious DiseaseDrug Safety & Toxicology
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