LA officials advise against raw pet foods after bird flu outbreak in cats

The following are excerpts from a message to veterinarians regarding the outbreak of highly pathogenic avian influenza among pet cats from the Veterinary Public Health division of the Los Angeles County Department of Public Health.

With scientific evidence of the linkage between contaminated raw products and cats developing severe or fatal H5 bird flu infection, Los Angeles County Department of Public Health (LAC DPH) recommends veterinarians strongly advise pet owners not to feed pets raw pet food diets, raw meat, raw poultry, and raw milk due to the risks associated with H5 bird flu.

Bird flu in cats that consumed raw pet food

Approximately 1-2 weeks after beginning to consume two commercially available raw food pet diets, all cats in a household of five strictly indoor-only cats became ill. Two of the five cats experienced acute respiratory distress and were humanely euthanized. Clinical signs in the cats included: upper respiratory symptoms, lethargy, reduced appetite, pollakiuria, ataxia, corneal edema, uveitis, and retinal detachment leading to permanent vision loss. As part of initial diagnostics, one severely ill cat had a respiratory PCR panel performed by a commercial veterinary laboratory, which came back positive for influenza A.

The cat’s sample was retested and influenza A positive at the California Animal Health and Food Safety Laboratory (CAHFS). The sample was then sent to the USDA’s National Veterinary Services Laboratory (NVSL) where whole genome sequencing (WGS) was performed and was confirmed to be positive for H5 bird flu (H5N1). The owner had unopened and opened packages of both commercially available raw pet foods that were fed to the cats. These samples were provided to the Animal Diagnostic Center laboratory of Cornell University where testing was performed in partnership with the FDA. Testing confirmed that product samples of both the opened and unopened Monarch Raw Pet food were infected with live and infective influenza A H5N1 virus.

In a separate single-cat household, a strictly indoor-only domestic cat was confirmed positive for H5 bird flu on December 31, 2024. The cat was fed three different brands of commercially available poultry-based raw pet foods. No pre-existing illness was identified prior to the cat becoming sick. Symptoms in this cat included fever, lethargy, anorexia, and acute wheezing. The cat remained hospitalized on oxygen for several days, was released and is recovering from illness. A respiratory PCR panel resulted positive for influenza A at a commercial laboratory, and both oropharyngeal and rectal swabs tested through Los Angeles County DPH were confirmed by NVSL as positive for H5 bird flu. The investigation is ongoing and testing of the raw pet food diets is currently underway by the FDA. Household members and veterinary clinic staff who had contact with the cat are also being monitored for symptoms of flu.

Bird flu in cats that consumed raw milk products

To date, in LA County, there have been two separate households with confirmed positive H5 bird flu in cats following the consumption of recalled raw milk products. In early December 2024, seven cats from one household became ill and five died in LA County after drinking the recalled raw milk sold for human consumption. On December 22, 2024, a cat from a different household was submitted for rabies testing after it died following the acute onset of severe neurologic signs (anorexia, disorientation, ataxia, confusion, circling, and seizures). Following a negative rabies test, a brain swab was collected and confirmed by NVSL to be positive for H5N1. Further investigation revealed that this cat lived in a household of eight indoor/outdoor cats that also had been offered milk from Raw Farm LLC in late November 2024; however, it was unclear how many cats had consumed the raw milk in this household. Over a period of three days, three of the eight cats in this household had become acutely ill and died, and only the one cat referenced above was tested for influenza.