{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T16:08:12Z","timestamp":1789834092604,"version":"4.0.1"},"reference-count":29,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T00:00:00Z","timestamp":1770768000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Highly pathogenic avian influenza (HPAI) A\/H5N1 has emerged as a cause of severe disease in domestic cats, but clinical data from field outbreaks remain limited. We retrospectively reviewed medical records, laboratory results, and ancillary examinations from 22 domestic cats with RT-qPCR-confirmed A\/H5N1 infection diagnosed in Poland in June 2023. To the best of our knowledge, we report the first comprehensive retrospective case series from the 2023 Polish outbreak, combining 22 laboratory-confirmed cats with detailed clinical timelines and laboratory findings. For each cat, the temporal progression of clinical signs, hematology, serum biochemistry, and, when available, imaging findings were evaluated. Post-mortem examination data were not systematically available in this retrospective cohort. Notably, six of these cats were strictly indoor cats that received raw poultry meat as part of their diet. Disease onset was acute, with fever, lethargy, and anorexia rapidly progressing to severe dyspnea and neurological signs, including ataxia, seizures, and paraplegia; case fatality was 100%, with a typical interval of \u22643 days from first signs to death or euthanasia. Hematologic changes were dominated by thrombocytopenia, lymphopenia, and marked eosinopenia, consistent with a systemic inflammatory\/stress leukogram. Biochemistry indicated marked tissue injury, with increased AST, LDH, and CK activities, whereas creatinine and urea remained largely within reference intervals, arguing against primary renal failure. Imaging supported the presence of interstitial to diffuse pneumonia. These data characterize the clinical and laboratory phenotypes of feline A\/H5N1 infection and underscore its importance as a rapidly fatal respiratory and neurological disease with One Health implications.<\/jats:p>","DOI":"10.3390\/pathogens15020200","type":"journal-article","created":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T09:15:12Z","timestamp":1770801312000},"page":"200","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Clinical and Laboratory Findings in Cats with Confirmed Avian Influenza A\/H5N1 Virus Infection During the 2023 Outbreak in Poland: A Retrospective Case Series of 22 Cats"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0845-0810","authenticated-orcid":false,"given":"Dawid","family":"Ja\u0144czak","sequence":"first","affiliation":[{"name":"Department of Infectious and Invasive Diseases and Veterinary Administration, Faculty of Biological and Veterinary Sciences, Institute of Veterinary Medicine, Nicolaus Copernicus University, Gagarina 7, 87-100 Toru\u0144, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2818-8506","authenticated-orcid":false,"given":"Anna","family":"Golke","sequence":"additional","affiliation":[{"name":"Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Ciszewskiego 8, 02-786 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3269-0774","authenticated-orcid":false,"given":"Karol","family":"Szyma\u0144ski","sequence":"additional","affiliation":[{"name":"Department of Virology, National Institute of Public Health NIH\u2013National Research Institute, Chocimska 24, 00-791 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ewelina","family":"Hallmann","sequence":"additional","affiliation":[{"name":"Department of Virology, National Institute of Public Health NIH\u2013National Research Institute, Chocimska 24, 00-791 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3665-5765","authenticated-orcid":false,"given":"Katarzyna","family":"Pancer","sequence":"additional","affiliation":[{"name":"Department of Virology, National Institute of Public Health NIH\u2013National Research Institute, Chocimska 24, 00-791 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6230-120X","authenticated-orcid":false,"given":"Aleksander","family":"Masny","sequence":"additional","affiliation":[{"name":"Department of Virology, National Institute of Public Health NIH\u2013National Research Institute, Chocimska 24, 00-791 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tomasz","family":"Dzieci\u0105tkowski","sequence":"additional","affiliation":[{"name":"Department of Medical Microbiology, Medical University of Warsaw, Cha\u0142ubi\u0144skiego 5, 02-004 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Olga","family":"Szalu\u015b-Jordanow","sequence":"additional","affiliation":[{"name":"Department of Small Animal Diseases with Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159c, 02-776 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,11]]},"reference":[{"key":"ref_1","unstructured":"Centers for Disease Control and Prevention (2025, October 02). 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