Dairy cattle have garnered most of the agriculture industry’s attention in the past year, with regard to outbreaks of the highly pathogenic avian influenza A (HPAI) H5N1.
Now, some researchers are turning their attention to other animals on the farm impacted by the virus: cats.
A new study published Monday in the journal Emerging Microbes & Infection addresses how domestic cats are affected by the virus and notes concerns such felines could offer the potential for HPAI H5N1 to evolve into a more dangerous version of the virus.
The study – which addresses the deaths of 10 cats in rural South Dakota last April – is not the first time researchers have raised concerns about the virus in cats and the potential for transmission to other mammals.
‘Urgent Need For Surveillance’
Researchers at the University of Maryland School of Public Health said in June 2024 that a “20-year review of bird flu in felines suggests urgent need for domestic cat surveillance.”
Kristen Coleman, an assistant professor in the UMD School of Public Health, and an affiliate professor in the University of Maryland Department of Veterinary Medicine, said, “As companion animals, domestic cats provide a potential pathway for avian influenza viruses to spillover into humans.” (Researcher Warns Pet Cats Risk Getting Bird Flu)
“We looked at the global distribution and spread of bird flu infections in feline species between 2004 and 2024 and found a drastic rise in reports of feline infections starting in 2023, with a spike in infections reported among domestic cats, as opposed to wild or zoo-kept animals,” added Coleman, who was not involved in the South Dakota study.
There is no study that shows transmission occurs from HPAI H5N1-infected cats to humans. Furthermore, current research shows HPAI H5N1 does not readily spread among humans, though studies have noted one or two key mutations could change that fact.
The virus often does take a deadly toll on felines. According to the University of Maryland’s School of Public Health, infected domestic cats have a mortality rate of up to 67%.
Last week, the Cornell University College of Veterinary Medicine Animal Health Diagnostic Center published directions online for veterinarians testing cats for highly pathogenic avian influenza (HPAI) .
AVMA Weighs In
“Dozens of cats are known to have contracted the virus, including barn and feral cats, indoor cats, and big cats in zoos and in the wild (e.g., mountain lions, tigers, leopards, and bobcats),” according to the American Veterinary Medical Association (AVMA). “Cats were already known to be susceptible to the H5N1 virus, with several feline cases linked to poultry or wild bird exposure before the cattle outbreak began,” AVMA said.
See Avian influenza A (H5N1) in cats for the Association’s recommended practices for dealing with any suspected of being infected by the virus.
‘A Possible Link’ To Local Cattle
The study published on Monday said virus-infected birds could have played a role in the South Dakota felines’ demise.
In addition, the report said: “The exact source of infection remains unclear; however, phylogenetic analysis of H5N1 sequences from two of the cats reveals a close genetic relationship to clade 2.3.4.4b strains previously detected in local cattle, suggesting a possible link.
“Additionally, the presence of bird feathers near the deceased cats indicates the likelihood that infection may have occurred through the consumption of virus-infected birds. However, because the disease typically requires several days to manifest post-ingestion, the exact timing of exposure is unclear. This evidence points toward a plausible cattle-to-bird-to-cat transmission pathway, supported by recent studies that identified H5N1 sequences across multiple species on affected farms, including dairy cows, wild birds, domestic cats, and raccoons.”
Many Mammal Species Impacted
According to USDA-APHIS, more than 200 mammal species in the U.S. have been infected by the virus since 2022.
Along with cows and cats, other U.S. mammals infected with the virus include a bottlenose dolphin, foxes, bobcats, mountain lions, coyotes, skunks, harbor and grey seals, opossums, squirrels, minks, otters, black bears, brown bears, polar bears, and a single pig on a backyard farm in Oregon, confirmed in late October.
The CDC encourages veterinarians and other individuals working with cats or other mammals that are suspected or confirmed positive for HPAI H5N1 to take precautions to prevent potential unprotected exposures.
The agency offers additional direction here: Highly Pathogenic Avian Influenza A(H5N1) Virus in Animals: Interim Recommendations for Prevention, Monitoring, and Public Health Investigations.
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