Genetic and molecular features of H10N3 avian influenza virus infection in humans in China, 2021

Influenza A virus (IAV) is an important zoonosis for multiple species of birds and mammals, causing mild to severe respiratory disease. Different subtypes of IAVs causing human infection have been reported previously, including H5N1, H7N9, H9N2, H5N6 and H10N8. In pressent study, we reported the genetic and molecular features of an emerging H10N3 IAV (A/Jiangsu/428/2021, JS/428) causing human infection in China. The results showed that JS/428 clustered in Eurasian lineages and closely related to H10N3/H10N8 IAVs isolated from chickens and H7N3 IAVs isolated from ducks for HA and NA gene, respectively. In addition, critical amino acid mutations associated with mammalian adaptation (Ala135Thr and Ser138Ala in HA), receptor-binding preference (Gln222Arg and Gly228Ser in HA), pathogenicity (Ala588Val in PB2, Leu473Val in PB1, Asn30Asp in M1, and Pro42Ser in NS1), and drug resistance (Ser31Asn in M2) have also been identified in JS/428. These molecular features indicate the potential for JX/428 to infect humans, thus, continuous monitoring of birds and mammals for this virus should be conducted in the future.