Isolation and Identification of Infectious Bronchitis Virus from Chickens in Sichuan, China

A nonhemagglutinating virus was isolated from kidneys and lungs of chickens suspected of having infectious bronchitis infection. Specific-pathogen-free embryonated chicken eggs were used as the cultural system. With the use of the ciliary activity of chicken embryo tracheal organ cultures as indicator system, the physicochemical properties of one of the isolated strains (SAIB3) were shown to be similar to infectious bronchitis virus (IBV) strain M41 (standard strain); whereas electron microscopy of the isolate showed coronavirus particles. Virus-neutralization tests were performed in tracheal organ cultures to compare the serotypes of five IBV isolates and six known IBV strains on the basis of reciprocal neutralization titers and euclidean distance. The cross-neutralization pattern indicated that one isolate was of the T-strain IBV serotype, another of the M41 IBV serotype, while others had partial serotype relationship to M41 and T-strains of IBV.