Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: Detection and molecular characterization of infectious bronchitis virus isolated from recent outbreaks in broiler flocks in Thailand | J. Vet. Sci. 2009 10 3 219-223 DOI JOURNAL OF Veterinary Science Detection and molecular characterization of infectious bronchitis virus isolated from recent outbreaks in broiler flocks in Thailand Tawatchai Pohuang Niwat Chansiripornchai Achara Tawatsin Jiroj Sasipreeyajan Department of Veterinary Medicine Faculty of Veterinary Science Chulalongkorn University Bangkok 10330 Thailand Thirteen field isolates of infectious bronchitis virus IBV were isolated from broiler flocks in Thailand between January and June 2008. The 878-bp of the S1 gene covering a hypervariable region was amplified and sequenced. Phylogenetic analysis based on that region revealed that these viruses were separated into two groups I and II . IBV isolates in group I were not related to other IBV strains published in the GenBank database. Group 1 nucleotide sequence identities were less than 85 and amino acid sequence identities less than 84 in common with IBVs published in the GenBank database. This group likely represents the strains indigenous to Thailand. The isolates in group II showed a close relationship with Chinese IBVs. They had nucleotide sequence identities of 97-98 and amino acid sequence identities 96-98 in common with Chinese IBVs strain A2 SH and QXIBV . This finding indicated that the recent Thai IBVs evolved separately and at least two groups of viruses are circulating in Thailand. Keywords infectious bronchitis virus phylogenetic analysis S1 gene sequencing Thailand Introduction Infectious bronchitis IB caused by the IB virus IBV is a highly contagious disease and results in a significant economic loss to the commercial chicken industry. The disease frequently causes respiratory signs including gasping coughing sneezing tracheal rales and nasal discharge. In layer fowls respiratory distress and a decrease in egg production have been reported 10 . In addition some strains have been associated with kidney lesions 18 19 22 . IBV the causative agent of IB
