Wyoming State Veterinary Lab Statement: Domestic Cat Infected With HPAI

 

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Three days after the report of a domestic dog infected with HPAI H5 in Canada we are learning about a domestic cat infected with HPAI in Wyoming. The story was picked up and published yesterday by the Gillette News Record, before being widely reported online overnight. 

The original announcement, however, was posted by the WSVL several days earlier. 

While many details (e.g. date of detection, fate of the animal, etc.) are missing, and the the virus is simply referred to as HPAI, this is almost certainly due to the HPAI H5Nx clade 2.3.4.4b virus which has spread so thoroughly across the Americas over the past 16 months. 

Previously Wyoming had reported H5N1 spillover into mammalian wildlife (3 mountain lions and 1 fox) to the USDA.

First the announcement from the State Veterinary lab, after which I'll return with a bit more. 

Highly Pathogenic Avian Influenza in a Domestic Cat

WSVL diagnosed highly pathogenic avian influenza (HPAI) virus in a barn cat near Thermopolis, WY. We know that wild birds, particularly water fowl, have been affected in large numbers by HPAI, but in recent months we have detected the virus in wild carnivorous mammals including mountain lions and a red fox.

This is the first report of HPAI in a domestic cat in Wyoming, and it likely became infected from ingesting meat from wild waterfowl. Clinical signs for mammals include those that are associated with neurological signs including change in behavior, decrease in awareness of surroundings and loss of energy. These signs may be indistinguishable from an animal affected with rabies. For testing of domestic species, we recommend your veterinarian submitting the whole carcass.

Please contact the Wyoming Game and Fish Dept (WGFD) for disposal recommendations for any dead waterfowl your pets can access, or to report dead or sick wild carnivores. As the HPAI outbreak continues, please make sure that you are using gloves and masks when handling sick or dead mammals and birds. Report any sick wildlife to the WGFD through the online reporting tool at the link in the title.

Cats are unfortunately highly susceptible to HPAI H5  (see 2015's HPAI H5: Catch As Cats Can) along with other novel flu subtypes (see J. Virology: Virulence Of A Novel H7N2 Virus Isolated From Cats In NYC - Dec 2016).

While most known infections have been among large cats (either captive or wild), we have seen a few instances of domestic cats infected as well (see WOAH: France Reports Cat Infected With Avian H5N1),

In September of 2020, in J. Clin. Microb: Serological Screening Of Dogs & Cats For Influenza A - Europe,  we looked at the seroprevalence of influenza A in both dogs and cats from shelters and homes in the Netherlands.

While it was not all that surprising that evidence of past 2009 H1N1 infection was found in both dogs and cats, researchers also found evidence of avian H5, H7, and H9 virus exposure in cats and dogs (see chart below). 

The authors wrote:

We conclude that infection of cats and dogs with both human and avian IAVs of different subtypes is prevalent. These observations highlight the role of cats and dogs in IAV ecology and indicate the potential of these companion animals to give rise to novel (reassorted) viruses with increased zoonotic potential. 

An earlier study, 2015's Seroprevalence Of Influenza Viruses In Cats - China, looked at the seroprevalence of (avian origin) canine H3N2, along with two seasonal human flu viruses (H1N1 and H3N2) in cats, also reported surprisingly high levels of exposure. 

While the risk of contracting HPAI from a companion animal is undoubtedly very low, it is not zero. 

Which is why the CDC, and other public health agencies around the world, have issued guidance to pet owners on how to best protect their animals from undo exposure (see Bird Flu in Pets and Other Animals).