ETIDIOH - NEW

  {Excerpt} Since 1997, more than 1000 cases of highly pathogenic avian influenza A(H5N1) have been reported in humans . During this time, A(H5N1) viruses have evolved into dozens of clades , showing ever-expanding phylogenetic diversification and geographical spread . Over the past 5 years, clade 2.3.4.4b A(H5N1) viruses have exhibited rapid global expansion in migratory birds, with spillover to an increasing range of marine and terrestrial mammalian species . Among these species are dairy cattle , not previously recognised as a permissive host for influenza A viruses (IAV), leading to widespread clade 2.3.4.4b A(H5N1) outbreaks in herds in the USA and sporadic human infections linked with exposure to infected animals since March 2024. While person-to-person transmission has not been detected in the USA, the increased geographical distribution of and susceptibility of mammalian hosts to clade 2.3.4.4b A(H5N1) viruses has brought to the forefront a need to assess the pandemic risk ...

  Summary Background Highly pathogenic avian influenza H5N1 viruses of the A/Goose/Guangdong/1/1996 lineage pose a global threat to wildlife, domestic animals, and humans . Cross-species transmission events to mammals, including humans , in the past 4 years highlight this threat. For influenza A viruses, crucial determinants of cross-species and intraspecies transmission to and among mammals include attachment to and replication in respiratory airway epithelial cells . Although these determinants have been studied for H5N1 viruses in the past, limited studies for clade 2.3.4.4b viruses exist. Therefore, the aim of this study was to determine the ability of recent clade 2.3.4.4b H5N1 viruses to attach to human respiratory tissues, to replicate in human airway epithelial cells and the associated immune response. Methods In this in-vitro study, we investigated three H5N1 clade 2.3.4.4b viruses (H5N1Gull2022, H5N1Polecat2022, and H5N1Bovine2024) in comparison with previously studied 2....