KosAbility: H5N1 ‘avian’ flu found in cats

Avian flu kills more than wild birds and poultry—cats, dogs, pet birds, and their human care givers can all be infected, as have at least 19 other animal species. While documented cases in cats and dogs are rare, now is the best time to learn the signs and adopt avoidance measures. Human cases have primarily been via contact with infected poultry (one was from a cow), and risk of transmission to humans from infected cats and dogs is low. To be a bigger risk to humans, the virus would have to mutate and become more capable of infecting mammals. The recent discovery of avian flu infected U.S. dairy cattle in eight states, however, represents a new concern even though the cattle generally recover after a month or two..

For 150 years, the highly pathogenic avian flu has been spreading across the globe and now, since the risk to non-avian animals is increasing, ‘avian’ is not a suitable name and it should be referenced by its subtype—H5N1 influenza—until an official name is applied by the World Organization for Animal Health.

When H5N1 infected dairy cattle were discovered in the U.S. a month ago, researchers began to investigate the farms and discovered seven U.S. barn cats also infected. 

The potential of H5N1 to infect domestic cats isn’t new—29 cats in Poland were documented with H5N1 in June 2023 and all died. The surveillance report of that incident noted that genetic analyses of the viruses found in these cats were highly similar, suggesting the cats all were infected from the same source. After testing food samples from the associated households, the pathogen was detected in one poultry meat sample. 

On the U.S. farms, the afflicted cats were noticed due to showing respiratory and neurologic signs consistent with H5N1: 

• Conjunctivitis,
• Periocular swelling,
• Respiratory signs,
• Dullness,
• Depression, and
• Other neurologic signs (including circling and blindness).

All seven cats died and “it is not known whether the cats were infected from consuming diseased birds, drinking infected milk, direct contact with sick cows, or another mode of transmission.”

The World Organization for Animal Health’s pamphlet on H5N1 in domestic cats notes that the following are possible sources of infection for cats and dogs: 

• Bird droppings, 
• Dead and live wild birds,
• Contaminated water and feed, and
• Contact with contaminated footwear, vehicles, and equipment.

Pet birds, so far, have not been found with H5N1 but they could be exposed if they live with a cat (or human 🫤) who’s allowed outside or a cat who eats a raw diet. Humans with pets should be careful not to transport wild bird droppings and feathers into their homes, for example inadvertently on their shoes.

It is possible, while so far unlikely, that humans could be infected by their cat or dog, according to the CDC. One person on a dairy farm was infected by a cow, the first human case in Texas and second in the U.S. That patient’s main symptom was conjunctivitis (pink eye).

In 2016, the spread of bird flu from a cat to a person was reported in NYC. The person who was infected was a veterinarian who had mild flu symptoms after prolonged exposure to sick cats without using personal protective equipment. 

If your pet is showing signs of illness compatible with bird flu virus infection and has been exposed to infected (sick or dead) wild birds/poultry, you should monitor your health for signs of fever or infection.

Visit the CDC’s report on H5N1 detections to determine if it has been documented in your county.

No treatments exist for affected non-human animals. For human cases of H5N1, anti-viral drugs used for other flu types are effective and should be taken immediately when symptoms begin—get to the doctor right away and be tested for H5N1. Anti-virals can also be taken preventatively after a known exposure to an infected animal. More information is available on the CDC’s Bird Flu Infections in Humans page.

Treatment of infected surfaces (fomites) requires cleaning off dirt and debris before applying a disinfectant such as chlorine bleach, household ammonia, or iodine. Porous surfaces like wood are more difficult to disinfect unless they are covered by polyurethane. H5N1 persists on surfaces for about 26 hours and on human skin for about 4.5 hours.

The most recent outbreak of H5N1 influenza started in 2022. Since that time, the USDA has detected the virus in many non-avian species, including

• Dogs
• Captive big cats
• Mountain lions
• Bobcats
• Brown bears
• Black bears
• Polar bears
• Bottlenose dolphins
• Grey seals
• Harbor seals
• Red foxes
• Coyotes
• Fishers
• American martens
• North American river otters
• Raccoons
• Skunks
• Virginia opossums
• Abert’s squirrels

Keep your cats safe, keep them indoors. Be careful with your shoes, leave them outside the door if you’ve encountered bird poop.

Nature and your kitty thank you.

Updated to add this as a warning for people with dogs.

For those who can’t see Twitter, here is the message I think most important in that tweet.

Not just cats — certain dog breeds (like beagles are highly susceptible to H5N1 avian flu too. And such dogs can facilitate their adaptation towards humans eventually (since more dogs are around people than dairy cows).

Update 2. More human cases appeared as I was writing this story.

Text from the tweet.

Out of 33 dairy farms in 8 U.S. states (+1 dairy farm in Colorado), 23 people have been tested for highly pathogenic avian influenza H5N1 by states. Less than 1 person per farm. This seems a clear answer to the question: “Are we testing enough for H5N1?”