solation and Identification of Avian Infectious Bronchitis Virus

[Objective]The aim of the study was to isolate an avian infectious bronchitis virus(IBV) isolate from the diseased chickens and identify its characteristics.[Method]An IBV isolate was isolated from the diseased chickens in a chicken farm in Anhui Province and passaged blindly in chicken embryos to observe its pathogenicity.Then animal regression test was used to replicate bronchial congestion in SPF chickens.The S1 gene fragment was amplified and its sequence was aligned with the IBV vaccine strains.[Result]The results of HA assay showed that the allantoic fluid of the IBV strain had no agglutination activity toward chicken red blood cells.This result suggested that no Newcastle disease virus and avian influenza virus were found in the allantoic fluid.However,the allantoic fluid treated with 10 g/L trypsin solution could agglutinate chicken red blood cells,which is in line with the biological characteristics of IBV.After the SPF chickens were inoculated with the sixth passage of the IBV isolate,the clinical symptoms like bronchial congestion that were similar with those in clinic were observed.The results initially confirmed the isolation of an IBV isolate,which was named IBV XZ strain.[Conclusion]This study provides a theoretical basis for the prevention and treatment of avian infectious bronchitis.