In mid-November 2020, deaths of whooper swan were reported in the Yellow River Reservoir Area, China. In the present study, we describe the genetic characterizations and phylogenetic relationships of four clade 2.3.4.4b H5N8 highly avian influenza viruses (HPAIVs) identified from a sick whooper swan and environmental samples collected in the Yellow River Reservoir Area in late November 2020. They were closely related to recent H5Nx HPAIVs causing outbreaks in Eurasia in the 2020-2021 influenza season, suggesting these isolates might be imported into China via migratory birds. The newly identified H5N8 HPAIVs possessed Q226 and G228 (H3 numbering), indicating that they prefer to avian-like receptors. However, they had three mutations falling within known antigenic regions, including T144A in antigenic region A, T192I in antigenic region B, and N240D in antigenic region D. Our study highlights the risk of the rapid global spread of H5N8 HPAIVs and the necessity for continuous monitoring of avian influenza viruses in wild birds.
Funding
This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (CAS) [grant number XDB29010102], the Second Tibetan Plateau Scientific Expedition and Research Program (STEP) [grant number 2019QZKK0304], the National Science and Technology Major Project [grant number 2018ZX10101004-002], the Open Research Fund Program of CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology [grant number 2021SPCAS002], the Academic Promotion Programme of Shandong First Medical University [grant number 2019QL006], and National Natural Science Foundation of China (NSFC) [grant number 31870163]. L. L., S. L. and W. L. are supported by an Ecology and Evolution of Infectious Diseases (EEID) collaborative grant (BBSRC) [grant number BB/V011286/1]; NSFC [grant number 32061123001], and S. L. is additionally supported by Biotechnology and Biological Sciences Research Council (BBSRC) Institute Strategic Programme Grant to Roslin Institute from ‘Pathogen diversity, host specificity and virulence' [grant number BBS/E/D/20002173], and the Scottish Government Rural and Environment Science and Analytical Services Division. W.S. is supported by the Taishan Scholar Project of Shandong Province. Y.B. is supported by the National Science Fund for Distinguished Young Scholars [grant number 31822055], and Youth Innovation Promotion Association CAS [grant number 2017122].
