So far, 43 types of mammals have tested positive for bird flu in the U.S.
The bird flu cases are rising in cats. A pet from the Champaign-Urbana area was recently diagnosed infected with the virus.
Photo: Annette Meyer/Pixabay
Lethality and Transmission Risk
"Bird flu H5N1 infections in cats are usually serious and life-threatening, with a high mortality rate. Infected cats show severe clinical signs such as lethargy, fever, loss of appetite, difficulty breathing, discharge from the eyes and nose, and neurological issues like tremors, seizures, incoordination or blindness," Wang explains. "Domestic cats are companion animals and have close contact with humans, potentially transmitting viruses to owners. A previous report revealed a cat-to-human transmission of influenza A virus, so H5N1 transmission might be possible as well."
Infections have been reported most often after prolonged and unprotected exposure to an infected animal.
Although no confirmed cases of cat-to-human transmission of H5N1 have been recorded in the current outbreak, Wang and other experts warn that as the virus circulates in mammals, the risk of mutation increases. "Previously, H5N1 had limited infection in mammals. However, the new H5N1 involved in outbreaks since 2022 mutated and acquired the capability to infect different mammal species including domestic and wild cats. So far, 43 types of mammals have tested positive for bird flu in the U.S., with domestic cats being the highest number," Wang says.
Pathways of Infection
The Centers for Disease Control and Prevention (CDC) states that people can be infected with avian influenza viruses through contact with infected wild, stray, feral, or domestic animals. Infections have been reported most often after prolonged and unprotected exposure to an infected animal. The CDC has previously documented avian influenza transmission from mammals to humans in the U.S., including a case involving a cat in New York City in 2016 and a cow in 2024.
The virus has been detected in poultry and cattle, allowing it to enter the raw food supply. Concerns over food contamination led the U.S. Food and Drug Administration (FDA) to recall Savage Cat Food Large Chicken Boxes (84 ounces) and Small Chicken Boxes (21 ounces) due to the potential presence of H5N1. These products, with a “better if used by” date of November 15, 2026, were distributed in multiple states, including Arizona, California, Colorado, Maryland, New York, and Pennsylvania.
Pet owners who have fed their cats the recalled products should watch for symptoms of bird flu, including fever, lethargy, loss of appetite, reddened or inflamed eyes, nasal and eye discharge, difficulty breathing, and neurological signs such as tremors, seizures, or blindness. If a cat exhibits these symptoms, immediate veterinary attention is advised.
Public Health Concerns
Public health experts fear that as H5N1 spreads among mammals, the likelihood of a pandemic increases. The New York Times recently reported that domestic cats could serve as a critical pathway for the virus to evolve and potentially become more transmissible to humans. If the virus mutates or swaps genes with another flu virus, it could pose a greater threat to human populations.
"If you work with animals, wash your hands well after interacting with poultry, livestock or animals outside the household. I also would suggest changing clothing and shoes after interacting with animals or birds with unknown health status, before interacting with your own pets," Wang advised.
Prevention and Protection
With no available vaccine or antiviral treatment for H5N1 in cats, prevention is key. Experts recommend keeping cats indoors to limit exposure to infected birds and wildlife. Pet owners should also avoid feeding raw meat or raw milk to their pets and ensure they do not come into contact with potentially contaminated food sources.
Wang stresses the importance of vigilance among pet owners. "Cat owners should contact their veterinarians if they are concerned their pet has contracted bird flu. Tell the veterinarian if your pet has been exposed to raw meat, raw milk, backyard birds or wild waterfowl. Unfortunately, only supportive care is available for cats with bird flu, and no antiviral drugs are yet available."
Beyond pet care, experts urge the public to remain cautious when handling animals and animal products. Personal protective equipment (PPE) is recommended for veterinarians and those working closely with animals at risk of infection.
