Advances in Animal and Veterinary Sciences

Research Article
Adv. Anim. Vet. Sci. 7(s2): 57-62
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Marwa Esmaiel1*, Gamilat Kotb2, Fatma Abdallah2, Ahmed A.H. Ali2

1Veterinary Administration of Afafos, Sharkia Governorate; 2Department of Virology, Faculty of Veterinary Medicine, Zagazig University, 44511, Zagazig, Egypt.

Abstract | Infectious bronchitis virus (IBV) is a major respiratory viral pathogen affecting chickens. In the current study, 81 tracheal tissues from 27 vaccinated broiler chicken flocks exhibited respiratory signs and high mortality rate up to 80% were collected from eight Egyptian Governorates during the period from 2017 to 2018. Out of the twenty-seven examined flocks, nine flocks were positive for IBV using quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR). Virus isolation was carried out for the RT-qPCR positive samples in embryonated chicken eggs (ECEs) for four blind passages along with partial amplification of spike protein (S1) using RT-PCR followed by sequencing for two representative isolates. Based on the deduced amino acids sequence and phylogenetic analysis of the S1 protein, the IBV isolates reported in this study were categorized into two lineages. One isolate, IBV-Ch-KafrAshaykh-2017 (MN201589) was belonged to GI-23 lineage showed high homology in amino acids sequences ranged from 92.4-99.4% with Egy/variant1 strains and the other isolate, IBV-Ch-Sharkia-2018 (MN201590) was belonged to GI-1 lineage showed high homology in amino acids sequences ranged from 95.3-98.8% with classical IBV strains. Therefore, it is very important to track the continuous evolution of IBV strains circulating in Egypt for better understanding the genetic relationship between circulating IBVs and the vaccine strains that will help in improving IBV control.

Keywords | Egypt, Broiler chickens, Infectious bronchitis virus, RT-PCR, Phylogenetic analysis