Influenza A Virus in Cats

On 27 June 2023, Polish health officials notified WHO of unusual deaths in cats across the country. As of 11 July 2023, 47 samples have been tested from 46 cats and one captive caracal, of which 29 were found to be positive for influenza A (H5N1) Virus[1]. Fourteen cats are reported to have been euthanized, and a further 11 died, with the last death reported on 30 June 2023. The source of the exposure of cats to the virus is currently unknown and epizootic investigations are ongoing.

Some cats developed severe symptoms including difficulty in breathing, bloody diarrhoea, and neurological signs, with rapid deterioration and death in some cases. In total, 20 cats had neurological signs, 19 had respiratory signs, and 17 had both neurological and respiratory signs.

Sporadic infection of cats with Influenza A(H5N1) Virus has previously been reported, but this is the first report of a high numbers of infected cats over a wide geographical area within a country.

As of 12 July, no human contacts of cats that tested positive with Influenza A(H5N1) Virus have reported symptoms, and the surveillance period for all contacts is now complete.

The risk of human infections following exposure to infected cats at the national level is (still) assessed as low for the general population, and (still) low to moderate for cat owners and those occupationally exposed to H5N1-infected cats (such as veterinarians) without the use of appropriate personal protective equipment.

This specific Influenza A(H5N1) Virus has been circulating in wild birds and which caused outbreaks in poultry recently in Poland.

[1] WHO: Influenza A(H5N1) in cats – Poland - July 16, 2023. See here.