Comparison of SYBR green I real-time RT-PCR with conventional agarose gel-based RT-PCR for the diagnosis of infectious bronchitis virus infection in chickens in Morocco

BACKGROUND: A rapid, sensitive, and specific molecular method for the diagnosis of infectious bronchitis virus (IBV) infection is important in curbing infectious bronchitis outbreaks in Morocco and other countries. METHODS: In this study, an easy-to-perform SYBR green I real-time reverse transcriptase polymerase chain reaction (RT-PCR) targeting the nucleocapsid gene of IBV was developed and compared with conventional agarose gel-based RT-PCR for the detection of IBV infection. RESULTS: We found that the SYBR green I real-time RT-PCR was at least 10 times more sensitive than the agarose gel electrophoresis detection method. The assay exhibited high specificity for IBV infection. All negative controls, such as Newcastle disease virus, infectious bursal disease virus, and avian influenza virus, were not detected. CONCLUSION: The SYBR green I real-time RT-PCR test described herein can be used to rapidly distinguish IBV from other respiratory pathogens, which is important for diagnosis and control of infectious bronchitis outbreaks in Morocco. The test is a valuable and useful method as a routine assay for diagnosis of clinical IBV infection in commercial chickens.