On 27 June 2023, the IHR National Focal Point of Poland notified WHO of unusual deaths in cats across Poland. As of 11 July, 47 samples have been tested from 46 cats and one captive caracal, of which 29 were found to be positive for influenza A (H5N1).

Fourteen cats are reported to have been euthanized, and a further 11 died, with the last death reported on 30 June. The source of the exposure of cats to the virus is currently unknown and epizootic investigations are ongoing.

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

“Another pandemic caused by a new influenza virus is a certainty. But we do not know when it will happen, what virus strain it will be and how severe the disease will be,” said Dr Wenqing Zhang, the manager of WHO’s Global Influenza Programme. “This uncertainty makes influenza very different to many other pathogens,” she said.

H5N1 infection cases in cats have been reported previously, but this is the first time there has been a high number over a wide geographic area.

The H5N1 virus is of particular concern because of its risks to humans, even though it has never been shown to be easily transmissible between humans. Since last year, there has been an increase in outbreaks in Central and South America.

In view of this alert, WHO is working closely with the World Organization for Animal Health and the Food and Agriculture Organization of the United Nations.

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