Highly pathogenic avian influenze (HPAI), more commonly known as bird flu, not only infects poultry flocks (backyard and commercial) and dairy herds.

The influenza A H5N1 virus (the current prevalent variety of bird flu virus in circulation) has been found in a range of wildlife species in addition to wild birds. From deer mice to dolphins, from cougars to coyotes, no mammalian species is completely immune from infection.

In recent weeks, it has become clear that household pets also are at risk.

Which pets are most at risk?

In April 2023, a domestic dog tested postive in Canada for the H5N1 virus after chewing on a wild goose. The dog died a few days later.

Household pets that spend unsupervised time outdoors are at risk of coming into contact with infected wildlife, such as a sick or dead bird or rodent.

The risk is increased if the household also maintains a backyard poultry flock.

Caged birds may also be at risk, if they are allowed to fly free from time to time and come into contact with a wild bird.

Yet, even pets that are kept largely indoors and are under supervision while outside can become infected with the bird flu virus.

Bird flu and cats

Cats are more susceptible to bird flu infections than dogs. There have been several reports of barn cats and feral cats becoming as a result of exposure to H5N1 on dairy farms.

Domestic indoor cats also are at risk.

Recently, Food Safety News reported on a case involving three cats in one household that were fed raw milk from the California company, Raw Farm LLC in late 2024. Two of the cats died and a third became seriously ill. A fourth cat in the household, which did not drink any of the raw milk, remained healthy.

On December 3, 2024, Raw Farm LLC recalled all raw milk and cream products after the California Department of Food and Agriculture found multiple instances of H5N1 virus in the company’s raw milk.

The dairy’s owner, Mark McAfee, denied that his milk was the source of the virus that killed the cats, claiming that the H5N1 virus cannot survive for long periods in cold milk. However, a recent study funded by the National Institutes of Health determined that the H5N1 virus remained viable in refrigerated raw milk for five weeks with only a minor decline in virus levels.

The H5N1 virus can also be present in raw pet food.

On December 24, 2024, Northwest Naturals recalled one batch of Northwest Naturals brand 2lb Feline Turkey Recipe raw frozen pet food after it tested positive for highly pathogenic avian influenza (HPAI) virus. Testing was initiated after a cat that had been fed the raw pet food developed bird flu and died.

On December 31, 2024, the Los Angeles County Department of Health advised the public not to feed Monarch Raw Pet Food to their pets after the H5N1 virus was detected in a sample. Again, testing was initiated after a cat that had been fed the product became ill and was confirmed to be infected with the virus.

On January 3, 2025, Monarch Raw Pet Food Company issued a statement claiming that there was no scientific evidence to substantiate the link between their pet food and the cat illness.

What is the FDA doing to protect pet health?

eFoodAlert reached out to the FDA Center for Veterinary Medicine (CVM) and received the following statement from a CVM spokesperson:

The FDA is tracking cases of Highly Pathogenic Avian Influenza in domestic and wild cats in California, Colorado, Oregon and Washington State that appear to be linked to eating contaminated food products. No human illness has been reported from handling these foods or through contact between people and the animals.

Some of the animals were fed raw poultry or raw poultry pet food, while others ate unpasteurized milk. The FDA is working with state and federal counterparts to gather more specific information about what animals ate which foods and when, and to coordinate test results of the animals and the suspect foods.

The FDA and state authorities routinely work together to surveil the animal food supply, including pet food. This includes conducting risk-based facility inspections and collecting animal food samples to help ensure safety.  The FDA may also collect samples “for cause,” such as when a pet food is suspected of being associated with human or animal illness. State authorities also regularly collect samples from retail settings and share test results with the agency. HPAI is an emerging contaminant in animal food. Analytical capacity is limited and pathogens like H5N1 can be difficult to detect because they might not be evenly distributed throughout the product (increasing the possibility of a false negative result).

Part of a pet food manufacturer’s responsibility is to bring a safe, wholesome product to market that is not adulterated under the Federal Food, Drug, and Cosmetic Act. As we learn more about the transmission of H5N1 in animal food, there are several practices that the FDA is encouraging pet food manufacturers and others in the supply chain to use to prevent HPAI transmission through animal food. These practices could include seeking poultry from flocks that are documented as having remained healthy throughout processing, and taking processing steps, such as heat treatment, that are capable of inactivating viruses and other hazards. 

All recent detections of H5N1 in cats had these things in common: the infected cats ate wild birds, unpasteurized milk, raw poultry, and/or raw poultry pet food. We know that cats are particularly sensitive to HPAI, and that very young, very old or immune-compromised animals are at greater risk of infection. The FDA continues to recommend that consumers avoid feeding pets any products that are recalled or from affected farms if those products have not been thoroughly cooked or pasteurized to inactivate the virus. If consumers are unsure of the origin of those products, it’s safest to follow the USDA guidelines for handling and thorough cooking before feeding. Animals should also be kept from hunting and eating wild birds.

What to watch for

Symptoms of a bird flu infection vary with the species. Here is a short list of what to watch for. Contact your veterinarian if you suspect one of your pets may be infected with bird flu. If you or a household member begins to exhibit symptoms associated with the bird flu virus, contact your healthcare provider.

In backyard flocks or pet birds

• Sudden death with no prior signs
• Low energy or appetite
• Purple discoloration or swelling of various body parts
• Reduced egg production, or soft-shelled/misshapen eggs
• Nasal discharge, coughing, or sneezing
• Lack of coordination
• Diarrhea

In cats and dogs

• Fever
• Lethargy
• Low appetite
• Reddened or inflamed eyes
• Discharge from the eyes and nose
• Difficulty breathing
• Neurologic signs, like tremors, seizures, incoordination, or blindness

In humans

• Eye redness or discharge
• Cough
• Sore throat
• runny or stuffy nose
• Diarrhea
• Vomiting
• muscle or body aches
• Headaches
• Fatigue
• trouble breathing
• Fever

Interested in learning more about food safety and the history of foodborne disease outbreaks and investigations?

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