This can be a KFF Well being Information story.
Greater than 80 home cats, amongst many different kinds of mammals, have been confirmed to have had chicken flu since 2022 — typically barn cats that lived on dairy farms, in addition to feral cats and pets that spend time open air and sure caught it by looking diseased rodents or wild birds.
Now, a small however rising variety of home cats have gotten sick from H5N1, the chicken flu pressure driving the present U.S. outbreak, after consuming uncooked meals or ingesting unpasteurized milk. A few of these cats died.
The pressure of chicken flu at present circulating has not tailored to effectively unfold amongst folks. And there have been no recognized instances of cat-to-human transmission throughout the present outbreak of H5N1.
Nonetheless, there’s all the time been the danger that cats, that are arguably solely semi-domesticated, may carry house a illness from a midnight prowl.
“Companion animals, and particularly cats, are 100% a public well being danger by way of the danger of zoonotic transmission to folks,” mentioned virologist Angela Rasmussen, who research illness development in rising viruses on the College of Saskatchewan’s Vaccine and Infectious Illness Group.
It is because we snuggle with and sleep in mattress with our cats. After we’re not wanting, cats drink from our water glasses and stroll on kitchen counters. So, cat house owners ought to concentrate on the continued unfold of chicken flu. “By lowering the danger to your cats, you cut back the danger to your self,” Rasmussen mentioned.
Rasmussen would not suppose pet house owners ought to be afraid their cats will give them chicken flu, however mentioned taking precautions is sweet for pets — and for public well being.
Indicators of chicken flu in cats embody runny nostril and discharge across the eyes, defined Michael Q. Bailey, president-elect of the American Veterinary Medical Affiliation.
H5N1 additionally causes neurological issues like dizziness and seizures, that are signs of rabies, too. Rabies is sort of all the time deadly, and it poses a risk to human well being, so any animal suspected of getting the viral illness have to be euthanized. Bailey encourages folks to make sure pets are up-to-date on their vaccinations.
Veterinarian Jane Sykes, who makes a speciality of infectious ailments in cats and canine on the College of California-Davis College of Veterinary Drugs, mentioned folks shouldn’t assume it is chicken flu if their cat is sick — even when their animal spends time open air or eats a uncooked weight-reduction plan.
Higher-respiratory diseases are frequent in cats, whereas H5N1 is “nonetheless fairly uncommon.”
Sykes offers her indoor cat, Freckles, common kibble completely. She advised NPR and KFF Well being Information she has no issues about Freckles getting H5N1 as a result of the heating course of of constructing dry or canned pet meals kills viruses.
Extra instances in cats, extra danger to people
Some folks feed their pets uncooked meat or unpasteurized milk as a result of they suppose it is a extra nutritious or pure weight-reduction plan. The American Veterinary Medical Affiliation’s web site discourages this as a result of foodborne pathogens like salmonella and listeria, and now the extremely pathogenic H5N1.
By conserving pets wholesome, veterinarians play a vital position in defending people from zoonotic ailments. The American Veterinary Medical Affiliation says the danger of H5N1 spilling over from a pet to an individual is “thought-about extraordinarily low, however not zero.”
State and native public well being companies, together with these in Los Angeles County and Washington state, have issued comparable warnings towards uncooked meals diets for pets.
Considerations for human well being are partly why the FDA introduced final month it’s now requiring cat and pet food firms to replace their security plans to guard towards chicken flu.
This got here after the Oregon Division of Agriculture found a cat that was “strictly an indoor cat” had contracted H5N1 and died after consuming a frozen turkey product made by the uncooked pet meals model Northwest Naturals. It said that “assessments confirmed a genetic match between the virus within the uncooked and frozen pet meals and the contaminated cat.”
Northwest Naturals voluntarily recalled that batch of its frozen turkey-based product. The corporate advised KFF Well being Information and NPR that the recall concerned “a small product run” and that it has issues concerning the accuracy of the Oregon Agriculture Division’s testing.
Los Angeles County’s public well being division mentioned 5 cats from two households examined constructive for chicken flu after ingesting unpasteurized uncooked milk from the Uncooked Farm dairy in California’s Central Valley.
Uncooked Farm voluntarily recalled its milk and cream after retail merchandise examined constructive for H5N1, however it denies any meals questions of safety, calling the priority “a political situation.”
Veterinarians additionally warn pet house owners to not enable cats unsupervised time outdoors as there’s the danger of them getting H5N1 by interacting with different animals which may carry the illness.
“This can be a very scary virus, on condition that it might infect so many alternative host species,” mentioned Bruce Kornreich, director of Cornell College’s Feline Well being Middle.
No less than one occasion of a cat infecting an individual with chicken flu occurred in 2016. As NPR reported, a veterinarian in New York Metropolis caught the virus after having shut contact with contaminated cats. The vet skilled delicate signs and shortly recovered.
In that case, the pressure of chicken flu was H7N2, not the H5N1 that’s now circulating within the U.S.
H7N2 is a really completely different kind of virus, Sykes defined. However she mentioned it exhibits that cat-to-human transmission of avian influenza is theoretically attainable.
There is not a number of analysis on transmission of chicken flu from companion animals like cats or canine to people, although Rasmussen agreed it is undoubtedly a priority: The extra infections you have got in animals, “the extra your luck is doubtlessly going to expire.”
Most individuals who’ve caught H5N1 are agricultural employees who had direct contact with contaminated poultry or cattle. Of a minimum of 67 confirmed human instances of H5N1 within the U.S., there’s been one fatality in an immunocompromised one that had contact with birds.
Typically, zoonotic illness researchers need extra H5N1 surveillance in companion animals of every kind. Even when the human demise toll of H5N1 stays comparatively low, it stays a public well being danger.
Probabilities for mutation
A part of the priority with this H5N1 outbreak is that chicken flu viruses change. Just some mutations may make this pressure adept at spreading between folks. And the extra individuals who catch H5N1, the extra probably it will adapt to be extra environment friendly, mentioned Suresh Kuchipudi, a virologist on the College of Pittsburgh College of Public Well being who researches zoonotic ailments. Kuchipudi has studied H5N1 in cats.
One other concern is one thing known as reassortment. If an animal or individual is contaminated with two viruses without delay, the viruses can commerce genetic materials, creating one thing new. That is frequent in influenza, so virologists are looking out for a case during which the chicken flu reassorts to make a virus that is way more contagious, and doubtlessly extra virulent.
Avian influenza or chicken flu.
BSIP/Common Pictures Group by way of Getty Pictures
Virologist Rasmussen is far more anxious about this taking place in pigs. Human respiratory physiology is extra like that of swines than felines. To date, the present outbreak of H5N1 has not reached industrial hog operations. Rasmussen hopes it stays that approach.
Kuchipudi mentioned that reassortments are comparatively uncommon occasions, however the final result is totally unpredictable. Generally the outcomes are benign, although it was probably a reassortment that concerned an avian virus that led to the 1918 flu pandemic, which killed an estimated 50 million folks. Within the century since, virologists have established a worldwide surveillance community to observe influenza viruses. Scientists say continued funding on this community is vital to making ready for and hopefully stopping one other pandemic.
Winter is “reassortment season” due to all of the influenza viruses circulating, Rasmussen mentioned. A reassortment in cats may technically be attainable since these pets sometimes get seasonal flu, however it’s extremely unlikely. Relatively, Rasmussen mentioned, it is extra probably {that a} cat would go H5N1 to a human who already has seasonal flu, after which a reassortment occurs within the sick individual. Whereas the danger is not zero, Rasmussen doubts this may occur. It might rely on how in poor health the human was, and the way a lot virus they’re uncovered to from their cat.
“Until the cat is admittedly shedding a ton of virus, and also you’re form of making out with the cat, I believe it will be onerous,” she mentioned.
Rasmussen and Kuchipudi warning there is not sufficient analysis to know for positive how a lot virus cats shed, and even how they shed the virus.
The Facilities for Illness Management and Prevention was poised to launch a brand new research about H5N1 in cats, however that was delayed when the Trump administration paused the Morbidity and Mortality Weekly Report. That investigation, revealed by means of emails obtained by KFF Well being Information in a public data request, discovered that home cats probably received chicken flu from dairy employees.
Scientists and public well being companies ought to query beforehand held assumptions about chicken flu, Kuchipudi urged. He famous that 20 years in the past no one would have predicted that chicken flu would infect dairy cattle the best way it’s now.
Canines appear to fare higher
The FDA says different domesticated animals, together with canine, can get chicken flu infections. There are not any confirmed instances of H5N1 amongst canine within the U.S., although in different international locations they’ve died from the virus.
There’s some disagreement and an total lack of analysis on whether or not cat biology makes them extra prone to H5N1 than different mammals, together with people, pigs or canine.
However cat behaviors, equivalent to their love of dairy and predation of untamed birds, put them at increased danger, Kuchipudi mentioned. Additionally, residing in teams may play a task as there are extra feral cat colonies within the U.S. than packs of stray canine.
There’s little or no folks can do concerning the H5N1 circulating in wild birds. As Rasmussen defined, “It is flying round within the skies. It is migrating north and south with the seasons.”
However she mentioned there’s so much folks can do to maintain the virus out of their properties.
That features limiting a pet’s publicity to H5N1 by not feeding them uncooked meals or unpasteurized milk, and making an attempt to maintain them from interacting with animals like rodents and wild birds that could possibly be contaminated with the virus.
This text is from a partnership that features NPR and KFF Well being Information.
