Circulation of three genotypes and identification of unique mutations in neutralizing epitopes of infectious bronchitis virus in chickens in Bangladesh

摘要: Infectious bronchitis (IB) is a highly contagious respiratory disease caused by a gammacoronavirus that has been circulating for many years in chickens in Bangladesh, resulting in significant economic losses. The aim of this study was to detect and characterize infectious bronchitis virus (IBV) from clinical outbreaks and surveillance samples. Real-time RT-PCR was used to detect IBV in pooled lung and tracheal tissue samples (n = 78), oropharyngeal swabs (n = 19), and pooled fecal samples (n = 13) from live-bird markets. Both respiratory and nephropathogenic forms of IB were suspected at necropsy (n = 7) from clinical outbreaks. Sequencing of hypervariable regions (HVR1-2 and HVR3) of the region of the spike gene (S) encoding the S1 subunit of five isolates revealed circulation of the Mass-like, QX-like, and 4/91-like genotypes of IBV in Bangladesh. Each genotype was extremely variable, as shown …