#18,278Until just over 3 months ago the USDA wasn't including infected cats on their wildlife with H5N1 list, despite the fact that we'd seen scattered reports across the nation (see here & here), and larger outbreaks in countries like Poland & South Korea.
That changed following the unexpected detection of HPAI H5 in dairy cattle, and reports of farm cats falling ill with the virus. On May 30th the USDA added 16 cats to the list, going back to March.
Ten days ago, in CAHSS/Animal Health Canada: HPAI H5N1 in Cats, we looked at the latest tally of cats included in the USDA's list (n=37). Yesterday afternoon the USDA added an additional 16 cats, bringing the total to 53.
All of these recent additions predate the bovine H5N1 era, with collection dates primarily from 2023, but with several going back to the fall and winter of 2022 (see list below).
We were aware of a few of these cases (see Nebraska Veterinary Diagnostic Center (NVDC) Report: 2 Domestic Cats Infected With HPAI H5N1), but as of February 16th of this year, only 7 H5N1 infected cats had been reported to WOAH by the United States.
A quick check of the most recent WAHIS update (Aug 30th) shows that number has only grown to 17.
I've no idea why less than 1/3rd of the listed cats have been reported to WOAH, or why it has taken - in some instances - nearly 2 years for some of these older cases to be revealed.
Particularly since the list we have is almost certainly incomplete. Only 32 states have reported HPAI in mammals of any type, which suggests some states aren't looking as hard as others for cases.But it is not a good look.
Even in states that are actively looking, mammals - including domestic cats - often die in remote and difficult to access places where their carcasses are quickly scavenged by other animals, meaning most never discovered or tested.
And of course, some of these animals are likely to survive the infection, and are never tested.
Three weeks ago the state of Colorado released some details on 6 feline infections, of which only one was connected to a dairy barn.
- Two of the 6 were indoor only cats, with no known exposures to the virus
- Three of the 6 were indoor/outdoor cats, which may have hunted mice and/or small birds
- Five of the 6 presented with respiratory symptoms and neurological impairment
The CDC offers the following Advice for Pet Owners:
As a general precaution, people should avoid direct contact with wild birds and observe wild birds only from a distance, whenever possible. People should also avoid contact between their pets (e.g., pet birds, dogs and cats) with wild birds. Don't touch sick or dead birds, their feces or litter, or any surface or water source (e.g., ponds, waterers, buckets, pans, troughs) that might be contaminated with their saliva, feces, or any other bodily fluids without wearing personal protective equipment (PPE).More information about specific precautions to take for preventing the spread of bird flu viruses between animals and people is available at Prevention and Antiviral Treatment of Bird Flu Viruses in People. Additional information about the appropriate PPE to wear is available at Backyard Flock Owners: Take Steps to Protect Yourself from Avian Influenza.
