Global dispersion of high pathogenicity avian influenza (HPAI), especially that caused by H5 clade 126.96.36.199, has threatened poultry industries and, potentially, human health. An HPAI virus, A/northern pintail/Hokkaido/M13/2020 (H5N8) (NP/Hok/20) belonging to clade 188.8.131.52b, was isolated from a fecal sample collected at a lake in Hokkaido, Japan where migratory birds rested, October 2020. In the phylogenetic trees of all eight gene segments, NP/Hok/20 fell into in the cluster of European isolates in 2020, but was distinct from the isolates in eastern Asia and Europe during the winter season of 2017-2018. The antigenic cartography indicates that the antigenicity of NP/Hok/20 was almost the same as that of previous isolates of H5 clade 184.108.40.206b, whereas the antigenic distances from NP/Hok/20 to the representative strains in clade 220.127.116.11e and to a strain in 2.3.4 were apparently distant. These data imply that HPAI virus clade 18.104.22.168b should have been delivered by bird migration despite the intercontinental distance, although it was not defined whether NP/Hok/20 was transported from Europe via Siberia where migratory birds nest in the summer season. Given the probability of perpetuation of transmission in the northern territory, periodic updates of intensive surveys on avian influenza at the global level are essential to prepare for future outbreaks of the HPAI virus.
Keywords: H5N8; clade 22.214.171.124; highly pathogenic avian influenza.