Molecular Characterization of Is/1494-Like Strains of Infectious Bronchitis Virus (IBV) in Commercial Breeders and Layer Chicken in Egypt During Years 2012 to 2014

摘要

One of the major problems of avian Infectious Bronchitis Virus (IBV) is the frequent emergence ofnew variants. This research was conducted to survey the presence of IB outbreak in 17 chicken farms Locatedin 6 Governorates include (Dakhlia, Port said, Behira, Qaliobia, Sharkia and Giza) during 3 years from 2012 -2014and included breeders and layers. The chickens were suffering from respiratory signs ranged from slight tomoderate and decrease in egg production. Examination of 17 pooled samples including trachea, kidney, lungand oviduct by real time RT- PCR, revealed 15 samples were positive for IBV. The 500-bp of the S1 genecovering the hyper variable region-3 of 3 selected isolates were amplified and sequenced. Phylogenetic analysisrevealed that these viruses were separated into two groups, the first group is classic groups which includedGiza F118-7/2013 resembled H120 vaccinal strains of IBV. The second group (Dakahlia F247/2013 and QaliobiaF1006/2014) resembled Variant 2 viruses. Although all farms in this experiment were vaccinated by classic strainof IB as commercial live (IB -H120 / MA5 ) vaccine or inactivated vaccine, that provided little to poor protectionagainst new IB serotypes that have been circulated and isolated recently and lead to outbreaks in variousgovernorates in Egypt. It is necessary to monitor the evolving IBV strains in order to set up an effective controlstrategy of the disease in Egypt.