The Evolution and Molecular Characteristics of Polymerase Complex of H9N2 Avian Influenza Viruses in Egypt

H9N2 avian influenza virus is endemic in Egyptian domesticated birds since 2010.Due to their mammalian-like traits, H9N2 have crossed the species barrier resulting in mild to moderate infections. Currently, the H9N2 virus's capacity to contribute their genes to other AIVs, creating high and low pathogenic IAVs that might cross species barriers and infect people, is considered a global concern. It has been determined that the RNA-dependent RNA polymerase of viruses (vRdRp) (polymerase complex) activity possesses a crucial role in modulating AIVs host adaptability to mammals and controlling of the viral ability to cross species barrier. Our study is conducted to screen the molecular progress of polymerase complex of H9N2 virus in Egypt, sequencing of the three genes of the polymerase complex and molecular characterization of the obtained sequences were achieved. Our findings showed the presence of some point mutations in the three genes (PB2, PB1and PA) which had previously been linked to increased viral replication, virulence, pathogenicity of avian influenza viruses in mammals.