Avian Flu and Our Furry Friends

Are there risks for feeding raw to dogs and cats? Here's what the research says.

There seems to be some confusion around the avian flu transmission and the risk for dogs, so this week we did a deep dive. We cover whether raw and cooked feeding pose a risk to contracting avian flu as well as the risk to you and your family members. For new subscribers, and as a refresher, we briefly discuss raw feeding in general.

Before that here are this week’ recipes:

TLDR: Avian flu is concerning because it can affect different kinds of animals and has a high mortality rate in many species. So far humans and dogs don’t appear to easily susceptible to the current strain. However, cats appear to be vulnerable to severe disease from food and their asymptomatic humans.

Why the worry about avian flu?

Avian flu is concerning because it is both zoonotic (meaning that it can cause illness in different species) and has a high mortality rate. Most viruses bind to host-specific receptors on the surface of a cell and evolve to evade the immune defenses of a single species. Few viruses like rabies, some influenza and coronaviruses evolve the capability to attach to the cells and evade the immune system of multiple species.

When viruses can jump between humans and animals there can be unpredictable consequences.

1. Reservoir hosts: Because of their natural ability to jump between species, zoonotic viruses can persist in some animals without severe illness. As the virus continues to mutate it can reemerge periodically, making eradication practically impossible.

2. Severe disease: When these viruses make the jump to new species they often have no natural immunity, which can overwhelm the immune systems of new hosts.

3. Fast mutation: Many zoonotic viruses mutate very rapidly and can adapt to other hosts species while sometimes growing more contagious and more virulent.

Different species have different susceptibility to H5N1

According to researchers, avian flu is usually asymptomatic in wild birds which traditionally served as the reservoir to infect livestock and other animals. However, some strains, particularly since 2020, have had unusually high mortality rates, especially in certain species. Between 2023 - 2024 over 500,000 seabirds died in Peru and Chile alone. The virulence also impacted sea mammals as over 20,000 sea lions were reported to have died in South America.

Recent reports of outbreaks in U.S. dairy farms are causing concern about the possibility of H5N1 in milk. Farm workers are also reporting infections although they are still rare. According to the U.S. Department of Agriculture (USDA), “initial testing has not found changes to the virus that would make it more transmissible to humans.” The USDA further reports that cows usually have mild illness, with infection primarily affecting mammary glands.

Cow-to-cow transmission is likely

Scientists are now trying to understand how H5N1 is spreading through cattle herds and also how to stop transmission. Cattle in Idaho recently became sick after contact with cows trucked in from Texas, where the virus was circulating. This suggests that the virus can now pass between cows rather than just from infected birds, though it is still unclear exactly how the virus is spreading.

How susceptible are people and dogs?

Reported cases of H5N1 in dogs is rare. A 2024 cross-sectional study done in Washington state on hunting dogs showed that only 2% (4 of 194) of dogs were positive for antibodies to H5N1. None of the dogs were symptomatic of disease, while nearly 80% of dogs included in the study trained with live or dead birds at least 15 times in the preceding 12 months. Furthermore, only 12% were vaccinated for canine influenza virus. The researchers conclude that the avian influenza virus circulating in 2023 (which is the same lineage as the current virus) is not well adapted to dogs, and there is no evidence to suggest that it can pass between dogs.

In humans, more than 900 cases of avian flu have been reported since 1997, with just over half of them fatal. However, this is very likely a gross overestimate of fatality since asymptomatic and mild cases are unlikely to be reported. Just like dogs, this current strain of H5N1 is not well adapted for human cells. But, according to this article from Science (Journal) it appears that humans have the avian version of the cell receptor in our eyes. This could explain why some outbreaks of avian flu in people lead to conjunctivitis.

Can dogs or people get sick from food?

Currently it doesn’t appear that H5N1 can easily cause disease in dogs exposed to wild birds. Therefore, the risk from consuming raw food infected with the pathogen is even less likely. However, we still recommend gently cooked food, see below.

For people, the risks are also very low considering poultry is rarely, if ever, eaten raw. As long as raw poultry is handled with proper hygiene and cooked to temperature, the risk of contracting H5N1 from food becomes very very small. Currently the CDC reports that there are no confirmed cases resulting from properly handled and properly cooked food.

Cats appear to be susceptible to contracting H5N1 from food and people

In a report from South Korea in Emerging Infectious Diseases (Journal) researchers trace the death of three stray cats to improperly sterilized raw feed made from duck. The post mortem analysis showed severe congestion and swelling as well as influenza antigens in the lungs. Furthermore, some of the cats showed signs of infection in the brain, which suggests severe systemic disease. Researchers believe H5N1 was the cause of death for all the three cats.

There are several reports of feral/barn cats contracting severe illness from eating wild birds. Also, multiple reports of severe cases of H5N1 in exclusively indoor cats owned by asymptomatic dairy workers suggests that human to cat transmission is possible. At least one case was severe enough that the cat was euthanized.

Raw diets for dogs are still not recommended

Despite the risk for avian flu transmission from raw food being low, dogs are still susceptible to food borne illness. Virulent strains of salmonella and E. coli can infect dogs and make them sick. More importantly, however, studies show as many as 80% of raw diets are positive for salmonella, and dogs can shed virus for over a week after contact. This is particularly concerning for the young and immunocompromised.

The food supply in the U.S. is based on cooking. All of the handling, processing, and logistics assume that meat will be cooked by the end consumer. Sashimi-grade fish is typically frozen for an extended time in order to neutralize any pathogens. Cooking also helps to denature proteins in a way that makes them more digestible.

Finally, raw diets are hard to balance without supplements. Farming practices and specifically the feed of farmed animals creates nutrients and fatty-acid profiles that dogs would not encounter in the wild. In our opinion gently cooked food and a varied diet is superior to raw in almost every way. See this post for more detail.

That’s all for this week.

All the best,

Joelle and The Precious Creatures Team