Multiple Introductions of Highly Pathogenic Avian #Influenza Viruses into the High #Arctic: #Svalbard and Jan Mayen, 2022 - 2025
Abstract B etween 2022 and 2025, highly pathogenic avian influenza viruses (HPAIVs) of clade 2.3.4.4b, including four distinct H5 Eurasian (EA) genotypes , were detected in wild birds and mammals in the Svalbard Archipelago and on the island of Jan Mayen . We describe their epidemiology and genomic characteristics to improve understanding of HPAIV occurrence and transmission in the High Arctic . The initial cases in 2022 occurred during summer and involved a glaucous gull (Larus hyperboreus) and great skuas (Stercorarius skua) on Svalbard and Jan Mayen , representing the first detections of HPAIVs in the High Arctic . Three HPAIV genotypes were identified: EA-2020-C (H5N1), EA-2021-AB (H5N1), and EA-2021-I ( H5N5 ). In 2023 , HPAIVs were detected in a broader range of bird species, and retrospectively in an Atlantic walrus reported by another research group (Odobenus rosmarus rosmarus). Genotypes identified in 2023 were EA-2020-C (H5N1), EA-2021-I ( H5N5 ), and EA-2022-BB (H5N1)....