title: Phylogenetic distribution and predominant genotype of the avian infectious bronchitis virus in China during 2008-2009.
abstract: BACKGROUND
  The nephropathogenic avian infectious bronchitis (IB) caused unprecedented economic losses to the commercial chicken industry of China in 2008-2009. To investigate the prevalence of nephropathogenic IB in China, eighty IBV isolates from different provinces during 2008-2009 were identified by dwarf embryo test and RT-PCR.
  
  
  RESULTS
  The strains were mostly isolated in winter and spring with a wide age range of IB outbreaks, from 4 to 69 days. By the virus recovery trials, 70/80 of the strains resulted in the deaths or distresses of birds from nephritis. To learn more about the molecular evolutionary characteristics of the circulating field strains, the coding region of major spike 1 (S1) protein gene of these strains was RT-PCR amplified and sequenced. Compared to the published representative strains, nucleotides and amino acids sequence analysis indicated that the S1 genes of these strains and the reference strains displayed homologies ranging from 75.1% to 99.8% and from 73.1% to 99.8% respectively. S1 protein of the major pandemic strains contained 540 or 542 amino acids with the cleavage site of HRRRR or RRFRR. Phylogenetic analysis revealed that recent field isolates of IBV in China were mostly belonged to A2-branch (QXIBV-branch) and HN08-branch, only one isolate was belonged to Gray-branch and M41-branch respectively. Most of the 80 strains showed evolutionarily distant from vaccine strains.
  
  
  CONCLUSIONS
  The results of this study suggested that nephropathogenic IBVs were mainly A2-like strains in China during 2008-2009.
authors.affiliation: College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Ji
authors.forename: Jingwei
authors.initials: J
authors.lastname: Xie
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.forename: Dingming
authors.initials: D
authors.lastname: Shu
authors.forename: Kejing
authors.initials: K
authors.lastname: Zuo
authors.forename: Chunyi
authors.initials: C
authors.lastname: Xue
authors.forename: Jianping
authors.initials: J
authors.lastname: Qin
authors.forename: Hongmei
authors.initials: H
authors.lastname: Li
authors.forename: Yingzuo
authors.initials: Y
authors.lastname: Bi
authors.forename: Jingyun
authors.initials: J
authors.lastname: Ma
authors.forename: Qingmei
authors.initials: Q
authors.lastname: Xie
mesh_terms: D000818:Animals; D002645:Chickens; D002681:China / Q000453:epidemiology; D018352:Coronavirus Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D005838:Genotype; D001351:Infectious bronchitis virus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D058873:Pandemics; D010802:Phylogeny; D011201:Poultry Diseases / Q000453:epidemiology / Q000821:virology*