Ongoing genetic evolution of H9N2 avian influenza viruses in Iranian industrial poultry farms.

摘要: Despite the use of wide-scale vaccination programmes against H9N2 virus, enzootic outbreaks avian influenza (AI) have often occurred and caused serious nationwide economic losses, particularly in broiler chickens. In this study, haemagglutinin (HA) neuraminidase (NA) genes nine recent H9N2s a common vaccine strain were fully sequenced compared with other representative Iranian viruses. Phylogenetic analysis revealed that all viruses grouped into G1 sub-lineage different clusters which isolates (2014-2017) formed distinct cluster to group (1998-2004). All exhibited low pathogenicity AI connecting peptide feature an R/KSSR motif. Amino acid 226, located 220 loop receptor binding site, was leucine among viruses, characteristic human With overall gradual increase genetic diversity H9N2s, Bayesian skyline plots HA NA depicted fluctuation relative stable situation, respectively. It is recommended apply constant surveillance assess any viral adaptation evolutionary changes circulating field H9N2s. Moreover, antigenic characterisation prevailing seems be necessary for evaluating possible drift from strain.