The death of a domestic cat from bird flu is a reminder: raw pet diets are not safe.

There is ZERO reason pets should be fed raw diets. Stop endangering pets because of wellness influencer disinformation.

As a scientist — one that specializes in immunology and infectious disease — and a cat mom to 7 rescues (all formerly strays or abandoned), I will say this unequivocally: pet owners who deliberately put animals in harms’ way are committing animal abuse.

This includes refusal to vaccinate your pets and feeding them raw diets.

If this evokes a visceral reaction from you, good. It should. Wellness disinformation is rampant in the human health landscape, but also in veterinary health. And unfortunately, there are every fewer guardrails in place when it comes to combating pet health disinformation.

Just in the past week, reports have emerged from Santa Barbara, California and Washington County, Oregon that pet cats have died from bird flu (officially, H5N1 influenza), from being fed raw animal products by their owners. These deaths were fully preventable, so we aren’t going to enable misinformation that endangers more animals here.

Instead, we are going to tackle dangerous claims head-on.

There is ZERO reason to feed any pet raw diets. Full stop.

Raw pet food offers zero health benefits. Not only are they frequently nutrient-deficient, they are not safe and are at risk of serious contamination with multiple different pathogenic microorganisms - many of the same ones we discuss when talking about foodborne illnesses in humans.

If you have been told that raw pet food offers a benefit, please read on. Even if you don’t believe that, read on. Or share this with someone else. Because it might save a pets’ life.

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Why are cats getting bird flu from raw pet food? Well, that’s virology.

A bit of a refresher on influenza viruses (more detail here and here). Influenza viruses are a large family of viruses that have tropism for different species (more basic virology here), meaning different flu viruses preferentially infect different organisms.

In the case of the current strain of bird flu in North America, this is strain of influenza called H5N1, the letters and numbers denoting the variants of two key proteins: hemagglutinin and neuraminidase. H5N1 flu is an influenza A subtype that preferentially infects birds, although it *can* infect other species. This is why it’s often called avian influenza (or colloquially, bird flu).

This is because of how flu viruses infect different host cells.

All influenza viruses possess a hemagglutinin protein (that’s the H part of the H5N1) that binds to sialic acid receptors on host cells to infect them. However, each influenza virus has different specificity for slightly different configurations.

In the case of H5N1 flu — the strain causing the current avian influenza outbreak — this virus preferentially binds α2,3-linked sialic acid receptors (SAα2,3), predominantly found in the respiratory tracts of birds. This is why this virus is so efficient at infecting bird species. This H5N1 is also what we call highly pathogenic avian influenza (HPAI), which has a near 100% mortality rate among birds - wild and domestic.

In humans, we predominantly have a different sialic acid receptor: α2,6-linked sialic acid receptors (SAα2,6). The good news for us us that H5N1 influenza cannot bind as effectively to SAα2,6, which is why so far, human cases have been sporadic. The recent severe case of H5N1 in an individual in Louisiana shows some genetic mutations in the virus that caused that illness, mutations which, if they become dominant, could facilitate easier spread in people or more serious illness. More on that to come.

Cats have both α2,3-linked (SAα2,3) and α2,6-linked (SAα2,6) sialic acid receptors in their respiratory and gastrointestinal tracts. This means that cats are particularly susceptible to infection with H5N1 influenza in a manner similar to birds.

If a cat is exposed to the virus, they can become infected, develop illness, and die within days. This is true for all cats including domestic cat breeds (all are of the species Felis catus) but also wild cats such as bobcats, mountain lions, lions, tigers, and other felids. Indeed, 20 wild cats in a sanctuary in Washington state have died from the same bird flu in recent weeks.

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Cats become infected with H5N1 primarily by eating contaminated and infected raw meat

When we think of flu transmission, we often think of it in the context of humans - and in that instance, our seasonal flu viruses are considered respiratory viruses: the virus spreads person-to-person through respiratory droplets, aerosol droplets, and close contact.

However, because cats have α2,3-linked sialic acid receptors in their GI tract, cats can become infected through ingesting infected material. This is both through the physical process of ingestion, where influenza virions bind receptors on intestinal epithelial cells and also during the process of eating, where aerosolized food materials are inhaled by a cat and infect respiratory epithelial cells.

A note: humans do have α2,3-linked sialic acid receptors in the GI tract, but these are expressed at quite low abundance. In contrast, cats have high expression and distribution of the α2,3-linked sialic acid receptors that H5N1 binds throughout their respiratory and gastrointestinal tract.

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The biggest potential sources of H5N1 for domestic cats? Raw pet food.

We will save the discussion for why pet cats should always be indoor-only for a future piece, but if your cat is hunting birds because it is let outdoors, that is another major potential source of exposure.

In the absence of that though, cats are becoming infected after being fed raw food by their owners. In the recent deaths, these were linked to raw poultry and raw milk.

Meats and other animal products that raw pet food companies use are not “free from pathogens” - they are, in most cases, akin to human grade meats, which means they are intended to be cooked or pasteurized. Cooking meat will inactivate influenza viruses, as will pasteurization of dairy. But consumption of raw products means the virus can be very much intact.

Before you think otherwise, it has been confirmed that at least one death is directly caused by consumption of raw pet food. Genetic analysis of the pet cat that died in Oregon determined that the source of infection was raw turkey-based pet food from a company called Northwest Naturals. Since then, the company has issued a recall, but that isn’t going to eliminate the risk of H5N1 for cats.

That’s because the current spread of H5N1 among birds - both poultry and wild birds - is uncontrolled. Spread among dairy cattle is also uncontrolled. The uncontrolled spread has broader implications for potential spillover into humans (discussed here). But it also means that there is almost no way that raw poultry and dairy products are going to be free from contamination.

And that is a serious risk if you are feeding your cats raw food.

The mortality rate of HPAI H5N1 in cats can range from 50-100%.

That is true for both infection via respiratory and oral exposures. Symptoms will often present with lethargy, fever, respiratory distress, and gastrointestinal symptoms like vomiting and diarrhea. It also often presents with neurological symptoms like seizures, tremors, and ataxia (loss of muscle control). Incubation period ranges from 2-4 days after exposure and death can occur in less than a week.

Why on earth would you risk your cat's life by giving them raw meat that have no benefit?

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The bigger issue: raw pet food is not safe for domestic animals, H5N1 influenza or otherwise.

Just like food safety matters for people, the same is true for your pets. Raw food is a major source of foodborne illness for humans and animals alike. Why on earth would you consider feeding your pet that?

Dogs have reduced expression of α2,3-linked sialic acid receptors compared to cats, so overall risk of contracting bird flu from raw meat for pet cats is a greater concern. That being said, the risk of the pathogens discussed below are still very much real for your pet dogs.

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Raw pet food has NO health benefits to pets, it only poses health risks.

I don’t care what some social media influencer claims. Raw food means that it is not cooked to kill disease-causing microorganisms. If you wouldn’t eat raw poultry, why would you feed your pet that?

I get it. The appeal to nature fallacy is rampant in pet disinformation. Claims like “their wild ancestors eat raw meat, so it’s fine!” are all over the place.

This is not only the appeal to nature fallacy but also the false analogy fallacy. Let’s discuss some key points:

1. Domestic cats and dogs are not wild animals. They are species humans created by genetically modifying wild animals over years and years and years. That means their biology is not the same as a different specie. Your chihuahua is not a wolf or a coyote. Your Scottish fold is not a bobcat.

2. Wild animals are exposed to LOTS of disease-causing pathogens when they hunt and kill prey. This is the most absurd part of this justification for why people think it’s acceptable to feed their domestic animals raw meat. Y’all. There are TONS of pathogens that are in animals that wild cats and canines might hunt and eat. Many of these can and do survive the trip through the stomach and can cause illness after ingestion.

You’ve got your bacterial pathogens:

Some you’ve heard of: Salmonella species, Escherichia coli, Listeria monocytogenes, and Campylobacter - all bacteria found in a variety of prey animals like rodents and birds. You’ve also got other bacterial pathogens like Leptospira, also naturally found in rodents and waterfowl. Then you’ve got ecological bacterial pathogens like Clostridium species including C. botulinum (yep, the one that causes botulism) and C. perfringens, bacteria that are ubiquitous in the soil and can be picked up by an animal feeding off the ground. You’ve even got Yersinia pestis - the bacteria that causes plague (that plague, yes, the Black death), which is transmitted by infected fleas that are frequently found on wild rodents. Wild animals can even pick up Mycobacterium tuberculosis (tuberculosis) and Bacillus anthracis (anthrax bacterium), and so can your pets, if you’re allowing them to eat raw meat products.

You’ve got your viral pathogens:

Yes, there is H5N1 avian flu to contend with. There’s also rabies virus which can be transmitted to wild animals during ingestion of an infected animal (or unvaccinated pets). Other potential viruses that can be transmitted to animals via ingestion include canine distemper virus (raccoons and foxes), and hantaviruses (rodents are the natural reservoir).

You’ve got LOTS of parasites:

I wrote about the broad umbrella of parasites here. Ones wild predators might contend with include Toxoplasma gondii, a protozoan that causes Toxoplasmosis in many animals, including humans. You’ve got Trichinella species, roundworms frequently in wild rodents, boars, and other animals. There’s also Echinococcus species, tapeworms that cause various parasitic diseases including serious illness in dogs. Sarcocystis is a protozoan parasite that causes rice breast disease in birds, infects many species both wild and domestic, and can be transmitted to animals that consume cytes. There’s even the raccoon roundworm, Baylisascaris procyonis, which is found in rodents and raccoons.

Fungal pathogens exist too:

Histoplasma capsulatum causes histoplasmosis and is commonly found in many wild animals including rodents, bats, birds, opossums, and more. It can also be present in the environment in infected feces.

So, is the logic here that you want to subject your pets to all these things too, because wild animals have to contend with them?

3. Wild animals die prematurely because of all of these pathogens. So, no. Raw meat isn’t “superior,” it’s actually frequently filled with disease-causing microbes and parasites. Wild animals have decreased life expectancy and health due to direct and indirect impacts of contending with these diseases.

   Wild wolves typically don’t live longer than 8 years, whereas in captivity can live up to 16-20 years. Red foxes usually don’t live longer than 5 years in the wild, whereas in captivity, they can live up to 14 years. Wild lions typically don’t live beyond 14 years, but in captivity can live up to 25 years. Wild mountain lions typically don’t live beyond 13 years, but can live up to 20 years in captivity. Same is true for bobcats, which typically live 7-10 years in the wild, but can live up to 25 years in captivity. Now, that’s not to say we should put all wild animals in captivity - but the reduction in life expectancy in the wild is driven primarily by premature death directly from these diseases as well as poor health, inability to hunt and feed, and wasting as a result of those indirect impacts of being sick. Plus, you know, veterinarians and veterinary nutrition experts that are there to take care of and ensure these animals in captivity are receiving medical care and proper nutrition.

So, all of these pathogens can be potentially found in wild prey, but many of them are also found in raw prepared meats that you might buy as part of your pet’s diet. These include H5N1 influenza, all of the bacterial pathogens listed, and more. These pathogens can get into that raw food - poultry, beef, lamb, through the fact the animal itself harbored the microbes and since it isn’t cooked, they’re not killed, or through contamination during the food processing steps before it gets to you.

Not only that, but if you are handling contaminated raw food at your house, it also means you are potential exposing yourself and your family members to the same pathogens you’ll also be exposing your pets to.

The good news: there’s a pretty easy way to reduce your pet’s risk of all of these deadly diseases. It’s not feeding them raw food.

There’s a saying, right? If you know better, you do better. Wild animals aren’t pets, so we can’t do better by them. But domestic dogs and cats ARE pets, so you can - and should - be doing better. And that means not feeding them raw food that can be contaminated with all of these things listed above.

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Freezing doesn’t inactivate H5N1 influenza virus, or many of other pathogens found in raw pet food.

Yep, lots of raw pet food companies are going on offense - making claims that they “ensure” their products are safe because they freeze them for x days before shipping them to you or such and such. Well, hate to break it to them, but they need some microbiologists on staff. Because freezing does not eliminate these pathogens.

Freezing in most cases merely slows down the replication of microorganisms. If freezing was effective at killing them, us scientists that work with infectious diseases would never have freezer stocks that we could thaw and conduct experiments with.

H5N1 influenza can survive freezing, including at normal freezer temperatures down to 0°F. More than that, once the virus is in infected meat, it can survive in frozen infected meat for up to years. This is because cold merely stabilizes viral membranes, so once the virus is warmed back up, it can return to its replication cycle.

Listeria, Salmonella, Campylobacter, E. coli, Clostridium (and the toxins they produce), Toxoplasma, Cryptosporidium, Histoplasma spores, and more can all survive freezing temperatures.

How do we eliminate risk of these pathogens? Cook food.

That’s right! Cooking meats and pasteurizing dairy products does a REALLY good job of killing and inactivating bacterial, viral, parasitic, and toxin-based agents that can cause disease in your pets (and in humans too).

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No credible veterinary expert agencies recommend raw pet diets. Period.

Not the American Veterinary Medical Association, Not the Canadian Veterinary Medical Association. Not the American Animal Hospital Association, or the World Small Animal Veterinary Association. None of them.

Why? Because there are serious risks associated with raw pet diets. Raw pet food has been found to have bacterial contamination far more frequently than cooked and prepared pet foods. That’s true for raw food you buy from a company or prepared at home, too.

There are also risks of nutrient deficiencies in raw pet foods, because they are frequently not formulated using the best veterinary nutritional science.

There’s also no evidence behind the claims made by influencers or "pet wellness" companies. Raw meat doesn’t magically cure your pet’s allergies, gut issues, urinary health, or skin problems. This is marketing misinformation, not science.

And just like the human wellness industry, raw pet food advocates undermine trust in reputable pet food manufacturers. They want you to think they’re offering something “better” or more “natural.” The truth? Their alternatives aren’t just inferior—they can be deadly. If you care about your pet, do not buy into this.

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We all must join in the fight for science.

Thank you for supporting evidence-based science communication. With outbreaks of preventable diseases, refusal of evidence-based medical interventions, propagation of pseudoscience by prominent public “personalities”, it’s needed now more than ever.

Stay skeptical,

Andrea

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“ImmunoLogic” is written by Dr. Andrea Love, PhD - immunologist and microbiologist. She works full-time in life sciences biotech and has had a lifelong passion for closing the science literacy gap and combating pseudoscience and health misinformation as far back as her childhood. This newsletter and her science communication on her social media pages are born from that passion. Follow on Instagram, Threads, Twitter, and Facebook, or support the newsletter by subscribing below: