Genetic evolution of Gallid herpesvirus 2 isolated in China.
Gallid herpesvirus 2 (GaHV-2), which causes Marek's disease in chickens and has caused extensive economic losses, has recently evolved increased virulence in China. To better understand the genetic basis of the pathogenic characteristics changed and increased virulence, we sequenced the genomes of six new GaHV-2 strains (LCC, LTS, WC/1203, JL/1404, CC/1409, and HS/1412) isolated from chickens with failed immunisation as well as one previously isolated Chinese GaHV-2 strain, J-1. Based on a multiple sequence alignment, several characteristic point mutations were detected in the open reading frames of the Chinese isolates. In addition, two deletions and an insertion were identified at the unique short region and terminal repeat short region junctions in Chinese isolates, and the insertion was a characteristic of the new Chinese isolates. According to a phylogenetic analysis, the GaHV-2 genome diverged substantially over the last two decades in China. Based on the internal repeat long region, the new isolates were closely related to very virulent or very virulent plus strains. Additionally, the new Chinese isolates diverged from the previously isolated strains J-1 and 814. In conclusion, our results provide evidence that Chinese GaHV-2 strains contain characteristic sequences, especially the new isolates. The observed genetic divergence in the new Chinese GaHV-2 strains over the last two decades may be related to observed changes in pathogenic characteristics and virulence.
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Hongchao
H
Lv
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Yanping
Y
Zhang
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Guorong
G
Sun
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Keyan
K
Bao
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Yulong
Y
Gao
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Xiaole
X
Qi
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Hongyu
H
Cui
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Yongqiang
Y
Wang
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Kai
K
Li
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Li
L
Gao
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Qing
Q
Pan
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China. Electronic address: xmw@hvri.ac.cn.
Xiaomei
X
Wang
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China. Electronic address: liucj93711@hvri.ac.cn.
Changjun
C
Liu
D000818:Animals; D002645:Chickens; D002681:China / Q000453:epidemiology; D004279:DNA, Viral / Q000235:genetics; D019143:Evolution, Molecular; D016679:Genome, Viral; D008381:Herpesvirus 2, Gallid / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D059014:High-Throughput Nucleotide Sequencing; D054643:INDEL Mutation; D008380:Marek Disease / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D016366:Open Reading Frames; D010802:Phylogeny; D017354:Point Mutation; D011201:Poultry Diseases / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D014774:Virulence
D004279:DNA, Viral
Gallid herpesvirus 2; Genome; Mardivirus; Virulence