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 RNAdependent 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.