GENETIC EVOLUTION OF LOW PATHOGENICITY H9N2 AVIAN INFLUENZA VIRUSES IN IRAN: ACQUISITION OF NEW MUTATIONS IN POLYMERASE ACIDIC (PA) GENES

The present study aimed to analyze and evolution of H9N2 influenza viruses in Iran from 2008 to 2009.. To determine the genetic relationship of Iranian viruses, the PA genes from ten isolates of H9N2 viruses isolated from commercial chickens in Iran during 2008–2009 were amplified and sequenced. The Iranian isolates did not show insertions or deletions within polymerase acidic (PA) gene with compared to the prototype, A/turkey/winconsin/66, but rather numerous point mutations were registered. The PA gene of Iranian viruses showed great genetic diversity and shared a high level of similarity with PA genes from H7 subtype rather than with established H9N2 Eurasian lineages. Our findings demonstrated striking extensive reassortment in the H9N2 viruses in Iran which has led to produce of novel genotypes. The emergence of these novel genotypes of H9N2 viruses and the sustained prevalence of these viruses in poultry warrant further surveillance of H9N2 viruses by completing genomic analysis.