{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T09:58:09Z","timestamp":1791280689317,"version":"4.1.0"},"reference-count":19,"publisher":"Wildlife Disease Association","issue":"4","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal of Wildlife Diseases"],"published-print":{"date-parts":[[2025,11,18]]},"abstract":"<jats:p>This report describes highly pathogenic avian influenza virus (HPAI) H5N1 infections in carnivores in Alaska, USA between 2022 and 2024, including a black bear (Ursus americanus), a brown bear (Ursus arctos), and the first known report of HPAI in an ermine (Mustela ermina). The two bears were cubs, and the ermine was a young adult. The black bear and ermine were euthanized after demonstrating neurologic signs, including circling, blindness, ataxia, or seizures. The brown bear was found dead. Gross lesions included swelling and congestion of the brain in both bears. Microscopically, all three individuals exhibited severe, nonsuppurative necrotizing meningoencephalitis, which was most prominent in the gray matter. Nonneuropathic microscopic lesions shared between both bears were multifocal random hepatic necrosis with lymphoplasmacytic hepatitis and mild interstitial pneumonia with bronchitis. The spectrum of additional lesions in individual animals consisted of acute necrosis within multiple other organs, including skeletal muscle, pancreas, kidney, retina, adrenal glands, and intestine. Immunohistochemistry demonstrated positive staining within neurons and glial cells in the brain, enterocytes and neurons of the myenteric plexus in the intestine, rare bronchiolar epithelial cells, renal tubular epithelial cells, and myocyte nuclei. Two HPAI-positive red foxes (Vulpes vulpes) and one positive Arctic fox (Vulpes lagopus) with incomplete histopathology are briefly discussed, as they demonstrate potential for co-infections with HPAI and canine distemper virus or rabies virus.<\/jats:p>","DOI":"10.7589\/jwd-d-25-00023","type":"journal-article","created":{"date-parts":[[2025,11,18]],"date-time":"2025-11-18T14:18:12Z","timestamp":1763475492000},"page":"1077-1083","source":"Crossref","is-referenced-by-count":6,"title":["Pathologic Characterization of Highly Pathogenic H5N1 Avian Influenza Virus Infections in Wild Mammals in Alaska, USA"],"prefix":"10.7589","volume":"61","author":[{"given":"Kimberlee B.","family":"Beckmen","sequence":"first","affiliation":[{"name":"Division of Wildlife Conservation, Alaska Dept of Fish and Game, 1300 College Road, Fairbanks, Alaska 99701, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kathleen A. Burek","family":"Huntington","sequence":"additional","affiliation":[{"name":"Alaska Veterinary Pathology Services, 23834 The Clearing Drive, Eagle River, Alaska 99577, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Terry","family":"Spraker","sequence":"additional","affiliation":[{"name":"Colorado State University, College of Veterinary Medicine and Biomedical Sciences, Veterinary Diagnostic Laboratory, 300 W Drake Road, Fort Collins, Colorado 80526, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jayne","family":"Ellis","sequence":"additional","affiliation":[{"name":"Division of Wildlife Conservation, Alaska Dept of Fish and Game, 1300 College Road, Fairbanks, Alaska 99701, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"4415","reference":[{"key":"18","doi-asserted-by":"crossref","unstructured":"MM Uhart, RET Vanstreels, MI Nelson, et al.  \"Nat Commun.\"  15, \"Epidemiological data of an influenza A\/H5N1 outbreak in elephant seals in Argentina indicates mammal-to-mammal transmission.\" 9516 (2024)","DOI":"10.1038\/s41467-024-53766-5"},{"key":"2","doi-asserted-by":"crossref","unstructured":"CA Ahlstrom, MK Torchetti, J Lenoch, et al.  \"Emerg Microbes Infect.\"  13, \"Genomic characterization of highly pathogenic H5 avian influenza viruses from Alaska during 2022 provides evidence for genotype-specific trends of spatiotemporal and interspecies dissemination.\" 2406291 (2024)","DOI":"10.1080\/22221751.2024.2406291"},{"key":"9","doi-asserted-by":"crossref","unstructured":"G Graziosi, C Lupini, E Catelli, et al.  \"Animals.\"  14, \"Highly pathogenic avian influenza (HPAI) H5 clade 2.3.4.4b virus infection in birds and mammals.\" 1372 (2024)","DOI":"10.3390\/ani14091372"},{"key":"1","doi-asserted-by":"publisher","unstructured":"CA Ahlstrom, LC Scott, AB Reeves, et al.  \"Influenza A virus data from migratory birds, Izembek National Wildlife Refuge, Alaska (ver. 1.0, 2018; ver. 3.0, May 2025). U.S. Geological Survey data release.\"  (2025)","DOI":"10.5066\/F7JD4W2W"},{"key":"3","doi-asserted-by":"crossref","unstructured":"P Bessi\u00e8re, N Gaide, G Croville, et al.  \"Microbiol Spectrum.\"  12, \"High pathogenicity avian influenza A (H5N1) clade 2.3.4.4b virus infection in a captive Tibetan black bear (Ursus thibetanus): Investigations based on paraffin-embedded tissues, France, 2022.\" e03736 (2024)","DOI":"10.1128\/spectrum.03736-23"},{"key":"4","doi-asserted-by":"crossref","unstructured":"L Bordes, S Vreman, R Heutink, et al.  \"Microbiol Spectrum.\"  11, \"Highly pathogenic avian influenza H5N1 virus infections in wild red foxes (Vulpes vulpes) show neurotropism and adaptive virus mutations.\" e02867 (2023)","DOI":"10.1128\/spectrum.02867-22"},{"key":"5","unstructured":"\"First H5 bird flu death reported in United States.\"  (2025)"},{"key":"6","doi-asserted-by":"crossref","unstructured":"LE Davis  and M Kornfeld  \"J Neurol Sci.\"  187, \"Experimental influenza B viral myositis.\" 61 (2001)","DOI":"10.1016\/S0022-510X(01)00526-3"},{"key":"7","doi-asserted-by":"crossref","unstructured":"M Desdouits, S Munier, MC Prevost, et al.  \"PloS One.\"  8, \"Productive infection of human skeletal muscle cells by pandemic and seasonal influenza A(H1N1) viruses.\" e79628 (2013)","DOI":"10.1371\/journal.pone.0079628"},{"key":"8","doi-asserted-by":"crossref","unstructured":"EJ Elsmo, A W\u00fcnschmann, KB Beckmen, et al.  \"Emerg Infect Dis.\"  29, \"Highly pathogenic avian influenza A(H5N1) virus clade 2.3.4.4b infections in wild terrestrial mammals, United States, 2022.\" 2451 (2023)","DOI":"10.3201\/eid2912.230464"},{"key":"10","doi-asserted-by":"crossref","unstructured":"CG Himsworth, JM Caleta, AN Jassem, et al.  \"Emerg Infect Dis.\"  31, \"Highly pathogenic avian influenza A(H5N1) in wild birds and a human, British Columbia, Canada, 2024.\" 1216 (2025)","DOI":"10.3201\/eid3106.241862"},{"key":"11","doi-asserted-by":"crossref","unstructured":"BT Jakobek, Y Berhane, MS Nadeau, et al.  \"Emerg Infect Dis.\"  29, \"Influenza A(H5N1) virus infections in 2 free-ranging black bears (Ursus americanus), Quebec, Canada.\" 2145 (2023)","DOI":"10.3201\/eid2910.230548"},{"key":"12","doi-asserted-by":"crossref","unstructured":"A Murawski, T Fabrizio, R Ossiboff, et al.  \"Commun Biol.\"  7, \"Highly pathogenic avian influenza A(H5N1) virus in a common bottlenose dolphin (Tursiops truncatus) in Florida.\" 476 (2024)","DOI":"10.1038\/s42003-024-06173-x"},{"key":"13","doi-asserted-by":"crossref","unstructured":"W Puryear, K Sawatzki, N Hill, et al.  \"Emerg Infect Dis.\"  29, \"Highly pathogenic avian influenza A(H5N1) virus outbreak in New England seals, United States.\" 786 (2023)","DOI":"10.3201\/eid2904.221538"},{"key":"14","doi-asserted-by":"crossref","unstructured":"GF Rimmelzwaan, D van Riel, M Baars, et al.  \"Am J Pathol.\"  168, \"Influenza A virus (H5N1) infection in cats causes systemic disease with potential novel routes of virus spread within and between hosts.\" 176 (2006)","DOI":"10.2353\/ajpath.2006.050466"},{"key":"15","doi-asserted-by":"crossref","unstructured":"SJ Sillman, M Drozd, D Loy, et al.  \"J Comp Pathol.\"  205, \"Naturally occurring highly pathogenic avian influenza virus H5N1 clade 2.3.4.4b infection in three domestic cats in North America during 2023.\" 17 (2023)","DOI":"10.1016\/j.jcpa.2023.07.001"},{"key":"17","doi-asserted-by":"crossref","unstructured":"R Stimmelmayr, D Rotstein, MK Torchetti, et al.  \"Emerg Infect Dis.\"  30, \"Highly pathogenic avian influenza virus A(H5N1) clade 2.3.4.4b infection in free-ranging polar bear, Alaska, USA.\" 1660 (2024)","DOI":"10.3201\/eid3008.240481"},{"key":"16","doi-asserted-by":"crossref","unstructured":"E. Spackman,  \"Methods Mol Biol.\"  2123, \"Avian influenza virus detection and quantitation by real-time RT-PCR.\" 137 (2020)","DOI":"10.1007\/978-1-0716-0346-8_11"},{"key":"19","doi-asserted-by":"crossref","unstructured":"S Youk, MK Torchetti, K Lantz, et al.  \"Virology.\"  587, \"H5N1 highly pathogenic avian influenza clade 2.3.4.4b in wild and domestic birds: Introductions into the United States and reassortments, December 2021\u2013April 2022.\" 109860 (2023)","DOI":"10.1016\/j.virol.2023.109860"}],"container-title":["Journal of Wildlife Diseases"],"original-title":[],"deposited":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T21:47:51Z","timestamp":1791236871000},"score":1,"resource":{"primary":{"URL":"https:\/\/bioone.org\/journals\/journal-of-wildlife-diseases\/volume-61\/issue-4\/JWD-D-25-00023\/Pathologic-Characterization-of-Highly-Pathogenic-H5N1-Avian-Influenza-Virus-Infections\/10.7589\/JWD-D-25-00023.full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,11,18]]},"references-count":19,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2025,10,1]]}},"URL":"https:\/\/doi.org\/10.7589\/jwd-d-25-00023","relation":{},"ISSN":["0090-3558","1943-3700"],"issn-type":[{"value":"0090-3558","type":"print"},{"value":"1943-3700","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,11,18]]}}}