H5N1 Bird Flu in Cats: What Pet Owners Need to Know

September 24th, 2025 | Posted in General, Medical Articles

Sea lions, barn cats, celestial influence, and migrating waterfowl—what do they have in common? They’re all part of the unfolding story of H5N1, the bird flu that’s raising new questions for pet owners and veterinarians. Once thought to be caused by the stars, influenza now reveals a different kind of power: traveling the world and constantly evolving—through small mutations (antigenic drift) and, at times, big genetic reshuffles (antigenic shift).

The Big Picture: A One Health Issue

Bird flu, or avian influenza, has been a known threat for over a century, primarily affecting wild birds and poultry. The current strain, Highly Pathogenic Avian Influenza (HPAI) H5N1, has crossed over into mammals, including domestic cats, dogs, and dairy cattle. While human infections remain rare, H5N1 is a One Health issue, linking animal, human, and environmental health. Understanding this virus is essential for protecting pets, owners, and the wider community.

In March 2024, H5N1 was first detected in dairy cattle—likely after exposure to infected wild birds like grackles and pigeons found dead near farms. Soon after, cats on two of those farms developed respiratory signs, lethargy, and neurological issues. Many cases were fatal, and testing confirmed H5N1 infection. These were the first documented cases in domestic cats.

Since then, cases have been confirmed across the U.S. and internationally. According to USDA Animal and Plant Health Inspection Service data, over 40 domestic cats were reported infected in 2024.

H5N1 Bird Flu in Cats: Guidance for Pet Owners

Understanding how H5N1 spreads, what signs to watch for in pets, and what precautions to take can help protect your cat. Indoor/outdoor cats are at higher risk, but infections have also occurred in farm and household cats.

Primary Routes of Transmission

Ingesting infected animals: Cats can become infected by hunting or scavenging carcasses of infected wild birds, poultry, or other animals.
Consuming contaminated food products:
- Raw or unpasteurized milk: Cats on dairy farms with H5N1-positive cattle became infected after drinking raw milk.
- Raw meat or poultry: Raw pet food containing infected ingredients has been linked to infections.
Environmental exposure: Contact with areas contaminated by infected animals, including feces, saliva, or other secretions.
Fomites/contaminated people or objects: Rare cases suggest indoor cats may become infected through the virus carried on clothing, footwear, or objects from affected farms.

Symptoms of H5N1 in Cats

Respiratory signs: coughing, sneezing, nasal discharge
Neurologic signs: loss of coordination (ataxia), tremors, head tilting, circling, seizures, and sudden blindness
Other signs: lethargy, fever, loss of appetite, sudden death

Prevention: How to Protect Your Cat

Keep cats indoors, particularly near farms or areas with wild birds
Avoid raw diets and unpasteurized milk
Prevent cats from scavenging dead birds or livestock
Practice good hygiene after handling poultry, livestock, or bird feeders
Regularly monitor indoor/outdoor cats for sudden illness or neurologic signs and seek veterinary care promptly.

H5N1 is a constantly evolving virus, jumping species, modifying surface proteins, and reminding us that vigilance is crucial. Veterinary teams play a vital role in early detection, testing, and educating clients, while pet owners can lower risk by keeping cats indoors, avoiding raw diets, and monitoring for sudden illness. Together, awareness, action, and collaboration help protect animals, people, and the broader community from this evolving threat.

Learn More:

References:

“Avian Flu: An Emerging and Evolving Threat to Humans and Animals.” UC Davis Grand Rounds, May 2025, www.youtube.com/watch?v=zsjNyrrEFTU.

“Avian Influenza (Bird Flu) Information for Clinicians and Veterinarians.” New York State Department of Health, www.health.ny.gov/diseases/communicable/influenza/avian/. Accessed 2 May 2025.

“Avian Influenza A (H5N1) in Cats.” American Veterinary Medical Association, www.avma.org/resources-tools/animal-health-and-welfare/animal-health/avian-influenza/avian-influenza-h5n1-cats. Accessed 2 May 2025.

“Considerations for Veterinarians: Evaluating and Handling of Cats Potentially Exposed to Highly Pathogenic Avian Influenza A(H5N1) Virus.” Centers for Disease Control and Prevention, May 2024, www.cdc.gov/bird-flu/hcp/animals/index.html.

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Allison-Black, Kate. “HPAI in Shelters and Colonies: Practical Mitigation and Community Strategies.” Canadian Animal Shelter & Community Medicine, 14 July 2025.

Bemis, Ian Gill. “Avian Influenza in Cats: Latest H5N1 Updates with Ian Gill Bemis.” AAHA HPAI Recap, 13 June 2025.

Influenza A(H5N1) Infection in Companion Animals: Guidance for Veterinary Clinics. Minnesota Department of Health, July 2024, www.health.state.mn.us/diseases/flu/current/factsheetforfetclinics.pdf.

“Interim Guidance for Employers to Reduce Exposure to Avian Influenza A Viruses for People Working with Animals.” Centers for Disease Control and Prevention, www.cdc.gov/bird-flu/prevention/worker-protection-ppe.html. Accessed 2 May 2025.

Weese, J. Scott. “WRVMA Webinar: H5N1 in Wildlife and Domestic Animals: Clinical and Zoonotic Considerations.” Mar. 2025.

Kelly, Terra, et al. “H5N1: A Feline Case Study and Expert Insights on Managing Cases in Your Practice.” AAHA, 29 Mar. 2025, www.aaha.org/trends-magazine/publications/h5n1-a-feline-case-study-and-expert-insights-on-managing-cases-in-your-practice/.