The American Veterinary Medical Association has issued recommendations for keeping pets and backyard flocks safe from highly pathogenic avian influenza, and the recommendations are also a useful guide for humans. In an interview with News Bureau life sciences editor Diana Yates, Stephany Lewis, a professor of zoological medicine at the University of Illinois Urbana-Champaign and director of the University of Illinois Wildlife Medical Clinic, explains the risks of HPAI to pets and people.
What kinds of contacts can lead to infection in pets and humans?
Pets may become infected with HPAI if they eat dead infected birds, eat raw meat from infected birds or drink unpasteurized milk from infected cows. Some raw pet foods have been linked to HPAI infection and deaths in house cats. Other routes of transmission, such as inhalation or ingestion of aerosolized secretions or feces from infected birds, are also possible but have not yet been confirmed.
In humans, most HPAI infections have occurred from unprotected direct contact with infected animals — usually poultry or cattle — or surfaces contaminated with feces or respiratory secretions from infected animals. The virus can enter through a person’s eyes, nose, mouth or via inhalation.
No infections have been reported from ingestion of properly cooked poultry or pasteurized milk, but improper handling of raw poultry products or ingestion of undercooked meat or unpasteurized milk could result in infection in humans as well as pets.
Cats, dogs and other pets are known to find and play with dead or injured wildlife when outside. How do we curb their natural inclinations to keep them safe from HPAI?
It is recommended to always keep cats indoors. Cats, dogs and other pets that do spend some time outdoors should remain leashed and closely monitored to keep them away from wildlife and poultry.
Are all dead birds or animals a risk, or only waterbirds?
Unfortunately, all dead animal carcasses have the potential to transmit HPAI. Waterbirds are the most affected species and they have the potential to transmit the virus without showing clinical signs, but a huge variety of wild and domestic bird and mammal species have died from HPAI.
How do people with backyard flocks prevent infection in their animals?
People with backyard flocks should keep their birds fully enclosed, with a solid roof covering them, to keep their poultry away from wild birds and their droppings. All feed, drinking water, equipment and other supplies should be stored out of reach of wild birds and rodents. The entire coop and run should be rodent proof, as mice and rats have also been shown to transmit avian influenza. Hardware cloth with 1/4-inch openings can be used around the entire perimeter and floor of the run or buried several inches underground to prevent rodents from burrowing, and 1/4-inch hardware cloth can also be used to seal up any small openings in the coup or near doors.
Owners or caretakers of backyard poultry should not wear clothes or shoes with their birds that they have worn while caring for other birds or that they have worn while hiking or walking in locations where waterfowl are present. Ideally, bird owners should have footwear they only use around their own birds. Shoe covers can also be used. During HPAI outbreaks, do not allow human or animal visitors to your flock.
If you are concerned about HPAI in your flock, call your veterinarian first before bringing your birds to the clinic. If you have any suspicious deaths in your flock, contact your veterinarian so they can report the event to the state animal health official if applicable. Avoid handling dead animals, but if you need to handle any carcasses, be sure to use appropriate personal protective equipment, including goggles, an N95 mask, nitrile gloves, shoe covers and disposable coveralls. Double bag all carcasses and potentially contaminated materials and disinfect the outside of the bag with an antimicrobial effective against avian influenza.
Are some animals more susceptible than others?
Yes, there appears to be a range of susceptibility to this current strain of H5N1 amongst different species. Besides waterbirds, the next most frequently seen wild birds with HPAI-related morbidity and mortality are crows and raptors, but any bird can become sick with avian influenza.
Clinical signs in birds we see most frequently are cloudy eyes, a symptom of corneal edema, and neurologic signs like tremors, weakness, incoordination, inability to stand and seizures, but other vague, non-specific signs of illness can occur, or the animal may die suddenly without observed clinical signs.
The clinical signs of avian influenza in any species can mimic those of many other diseases, so there’s no way to know for sure an animal has avian influenza without laboratory diagnostics. As mentioned, waterfowl such as ducks and geese can contract and spread the disease without getting sick themselves.
Wild carnivores, such as foxes, bobcats and other wild felines, skunks, fishers, mink and even marine mammals such as seals have all been documented to get sick and die from avian influenza.
Felines, both wild and domestic, appear particularly susceptible to severe disease and death from this virus. Tragically, a wildlife sanctuary in Washington lost over half of their big cats to HPAI in December 2024.
In the past year, HPAI has also been documented in dairy cows in 16 states to date. The virus appears to be able to circulate between cows, sometimes without illness in the cows, and from cows to humans, which was the first likely mammal-to-human spread of this virus.
The first detections in pigs in the U.S. occurred in October 2024. Horses in the U.S. have not been documented with HPAI, but there is recently documented evidence of infections in horses in Mongolia.
Avian influenza cases in humans have been rare and largely mild. The Louisiana Department of Health just announced the first H5N1-related human death in the U.S. but note that person was over the age of 65 and had underlying medical conditions. There remains no evidence of human-to-human transmission of avian influenza to date.
What precautions are you taking at the University of Illinois Wildlife Clinic?
The Wildlife Medical Clinic is currently unable to accept waterfowl as patients per instruction from the Illinois Department of Natural Resources, the Illinois Department of Public Health and the Illinois Department of Agriculture. The clinic is accepting other injured birds and wildlife as usual, while taking extra precautions, including the use of PPE and careful disinfection protocols, to help protect our patients, resident ambassador animals and staff from HPAI.
Our clinic has a HPAI emergency response plan, which is periodically reviewed and updated by me and the College of Veterinary Medicine’s director of biosecurity and safety. We are conducting diagnostic testing for avian influenza and informing and encouraging anyone who has contacted an infected animal to reach out to their physician.
We are also encouraging the public to avoid contact with wildlife displaying signs of illness consistent with HPAI, and to report bird mortality events — the death of five or more birds — to IDNR district wildlife biologists. If you live in Illinois, you can find out who your district’s biologist is here. Reports can also be made to the U.S. Department of Agriculture Wildlife Services at 1-866-487-3297.