Emergence and potential transmission route of avian influenza A (H5N1) virus in domestic cats in Poland, June 2023

In June 2023, a fatal disease outbreak in cats occurred in Poland. Most cases tested in Poland (29 of 47) were positive for highly pathogenic avian influenza (HPAI) A (H5N1) virus. Genetic analyses revealed clade 2.3.4.4b with point mutations indicative of initial mammalian hosts adaptations. Cat viral sequences were highly similar (n = 21), suggesting a potential common infec-tion source. To investigate possible infection routes, our group tested food samples from affected house-holds. HPAI H5N1 virus was detected in one poultry meat sample.

Automated summary

A fatal disease outbreak in cats occurred in Poland in June 2023. Most cases tested were positive for highly pathogenic avian influenza A (H5N1) virus, with genetic analyses revealing initial adaptations to mammalian hosts. The cat viral sequences were highly similar, indicating a potential common infection source. Investigation of possible infection routes led to the detection of HPAI H5N1 virus in poultry meat samples from affected households.