Since 2022, there have been over 80 confirmed cases of domestic cats with avian flu, including barn cats on dairy farms, feral cats, and outdoor pets likely contracting the virus from hunting sick rodents or wild birds. A small but growing number of domestic cats have now fallen ill with H5N1, the strain of avian flu fueling the current outbreak in the country, after consuming raw food or unpasteurized milk, resulting in some fatalities.
The current strain of avian flu has not adapted to efficient human-to-human transmission, and there have been no known cases of cat-to-human transmission during the current H5N1 outbreak. Nevertheless, there has always been a risk that cats, potentially only semi-domesticated, could bring home a lurking disease.
“The pet animals, and especially cats, pose a 100% public health risk in terms of zoonotic transmission to humans,” said virologist Angela Rasmussen, studying disease progression in emerging viruses at the Vaccines and Infectious Disease Organization at the University of Saskatchewan.
People sleep with their cats. Cats drink from human water glasses and walk on kitchen countertops. Therefore, cat owners must be aware of the continued spread of avian flu. “By reducing the risk for your cats, you reduce the risk for yourself,” stated Rasmussen.
Symptoms of avian flu in cats include nasal discharge and around the eyes, as explained by Michael Q. Bailey, President-Elect of the American Veterinary Medical Association. H5N1 also causes neurological issues like dizziness and seizures, similar to rabies symptoms, posing a threat to both pet and human health.
Veterinarian Jane Sykes, specializing in infectious diseases in cats and dogs at the University of California-Davis School of Veterinary Medicine, advises against assuming avian flu if a cat falls ill, even if they spend time outdoors or consume a raw diet, as upper respiratory illnesses are common in cats while H5N1 remains “still quite rare.”
Sykes feeds her cat, Freckles, pet food. She told NPR and KFF Health News that she is not concerned about Freckles contracting H5N1 because the heating process for making dry or canned pet food kills viruses.
More cases in cats mean more risk for humans
Some individuals feed their pets raw meat or unpasteurized milk believing it to be a more nutritious or natural diet. The American Veterinary Medical Association website advises against this practice due to foodborne pathogens like salmonella, listeria, and now the highly pathogenic H5N1.
Veterinarians play an essential role in protecting humans from zoonotic diseases by keeping pets healthy. The association states that the risk of H5N1 transmission from a pet to a person is considered “extremely low but not zero.”
State and local public health agencies, including those in Los Angeles County and Washington state, have issued similar warnings about feeding pets raw food.
Human health concerns partly led the Food and Drug Administration (FDA) to mandate pet food companies update their safety plans to guard against avian flu. One way to reduce exposure to the H5N1 virus is to avoid feeding pets raw food or unpasteurized milk and try to prevent them from interacting with potentially infected animals like rodents and wild birds.
Possible mutations
Part of the worry with this H5N1 outbreak is the potential for avian flu viruses to change. Just a few mutations could make this strain capable of human-to-human transmission. Suresh Kuchipudi, a virologist at the University of Pittsburgh’s Graduate School of Public Health researching zoonotic diseases, has studied H5N1 in cats and emphasizes the importance of questioning previous assumptions about avian flu.
The Centers for Disease Control and Prevention (CDC) were set to release a new study on H5N1 in cats, revealing cats likely contracted avian flu from dairy workers, but this was delayed when the Trump administration halted the Morbidity and Mortality Weekly Report.
Researchers and public health agencies should increase surveillance of H5N1 in all types of companion animals. Even though the number of human deaths from H5N1 is relatively low, it remains a public health risk.
Dogs seem to be more fortunate
The FDA notes that other pets, including dogs, can contract avian flu infections. While no confirmed cases of H5N1 in dogs have been reported in the US, deaths have occurred in other countries due to the virus.
There is some disagreement and a general lack of research on whether the biology of cats makes them more susceptible to H5N1 than other mammals such as humans, pigs, or dogs. However, behaviors like cats’ love for dairy products and hunting wild birds put them at higher risk. Additionally, living in groups could play a role, with more colonies of feral cats than groups of stray dogs.
There is little that people can do about the H5N1 circulating in wild birds. “It’s flying in the skies. It’s migrating from north to south with the seasons,” explained Rasmussen. But there are many things people can do to keep the virus out of their homes.
This article, in partnership with NPR and KFF Health News, provides insight into the ongoing concerns surrounding avian flu in domestic cats and the potential risks to human health.
