Molecular Characterization of Avian Influenza Virus Subtype H9N2 in Poultry in Egypt During 2011-2013 with Emerging of a New Variant in Quails

摘要

Avian influenza virus subtype H9N2 has become established in poultry in Egypt and together withhighly pathogenic H5N1 causing serious threats in the field of poultry production. Since the first isolation ofH9N2 AIV in May 2011, continuous monitoring of this subtype in poultry population has occurred. Theepidemiological situation of H9N2 virus during the period from August 2011 to January 2013 was studied.The results of H9N2 virus detection indicated that these viruses were still circulating in different species ofdomestic poultry like chickens, ducks, turkeys and quails during that period. The H9N2 viruses were detectedin 343 commercial flocks and 17cases from house hold birds in 20 different Governorates. According to thephylogenetic analysis, the Egyptian H9N2 viruses can be subdivided into two subgroups based on HA genevariation. Both two subgroups were circulating during 2011to 2013 in different locations. The genetic analysisindicated 5-20 amino acid substitutions in HA gene in comparison to the original A/Quail/Egypt/113413v/2011virus. The highest variation was recorded in quail isolate (A/Quail/ Egypt/122313V/2012) which has beenisolated during 2012 and had 20 A.A. substitutions distributed along HA protein including the receptor bindingdomain and antigenic epitopes proposed to be a new variant of H9N2 virus in quail. The results from this workindicate the importance of periodical monitoring of circulating viruses especially in endemic countries like Egyptto update the epidemiological situation and that will help the efforts to control.