Genetic characterization of variant infectious bronchitis viruses detected in broiler chickens in south Egypt

الملخص EN

Avian Infectious bronchitis virus (IBV), a major pathogen of commercial poultry flocks, circulates in the form of multiple ever emerging variants threatening the poultry industry.

This study was conducted to survey the presence of IBV from Luxor Governorate during 2015 -2016.

Examination of 43 pooled samples including trachea and kidney homogenates by real time RT- PCR for N gene, revealed 35 (81.4%) out of 43 commercial broiler flocks were positive to IBV.

The 400-bp of HVR3 of the S1 gene of ten selected samples were amplified by RT-PCR, sequenced, and aligned for phylogenetic and amino-acid similarity analyses.

The ten IBV viruses share from 71% to 90.8% homologies between each other but are very different from the vaccinal strains (H120, MA5, M48, 4/91 and CR88) used in Egypt with 62.6 to 84.7 % similarities.

Phylogenetic analysis revealed that all the Luxor detected viruses were grouped within the Variant 2 IBV cluster together with the D1456-like Egyptian IBVs but in a different subcluster.

Monitoring the emerging IBV variants is extremely important for establishing an effective control strategy for the disease in Luxor and surrounding area.