Identification of a duck H9N2 influenza virus possessing tri-basic hemagglutinin cleavage sites genetically close to the human H9N2 isolates in China, 2022

Recently, the first human cases of H3N8 and H10N3 avian influenza viruses (AIVs) were documented in this journal. 1 Cheng D. Dong Y. Wen S. Shi C. A child with acute respiratory distress syndrome caused by avian influenza H3N8 virus. J Infect. 2022; 85 (PubMed PMID: 35577072. Epub 2022/05/17.): 174-211 Abstract Full Text Full Text PDF Scopus (12) Google Scholar , 2 Wu Z. Liu J. Chen S. Zhang H. Chang Y.F. Zhang X. et al. The emergence of the novel avian influenza virus (H10N3) in China, 2020-a cause for concern?. J Infect. 2022; 84 (PubMed PMID: 35123958. Epub 2022/02/07): e16-e8 Abstract Full Text Full Text PDF Scopus (1) Google Scholar The H9N2 virus, which continues to be the most frequent subtype of low pathogenic avian influenza virus (LPAIVs) circulating in chicken populations globally, has six internal genes that are shared by both H3N8 and H10N3 AIVs. Despite the fact that H9N2 AIVs infections often have only minor symptoms, they can nonetheless cause large economic losses since they can lead to secondary respiratory pathogens such Mycoplasma gallisepticum and infectious bronchitis virus. Moreover, H9N2 is a zoonotic virus that has share internal genes to other, more virulent subtypes like H5N1/N6/N8, H3N8, H7N9, and H10N8. 3 Liu D. Shi W. Gao G.F. Poultry carrying H9N2 act as incubators for novel human avian influenza viruses. Lancet. 2014; 8 (PubMed PMID: 24581684. Epub 2014/03/04): 869 Abstract Full Text Full Text PDF Scopus (0) Google Scholar In this study, we present the detection, genetic characteristics, and receptor binding properties of a novel H9N2 strain found in ducks in Guangdong, China in December 2022. The strain possesses tri-basic (PSRSRR/GLF) hemagglutinin cleavage sites (HACS) and is closely related to a recent human H9N2 isolate discovered in southern China.