title: Phylogenetic analysis of porcine parvoviruses from swine samples in China.
abstract: BACKGROUND
  Porcine parvovirus (PPV) usually causes reproductive failure in sows. The objective of the present study was to analyze the phylogenetic distribution and perform molecular characterization of PPVs isolated in China, as well as to identify two field strains, LZ and JY. The data used in this study contained the available sequences for NS1 and VP2 from GenBank, as well as the two aforementioned Chinese strains.
  
  
  RESULTS
  Phylogenetic analysis shows that the PPV sequences are divided into four groups. The early Chinese PPV isolates are Group I viruses, and nearly all of the later Chinese PPV isolates are Group II viruses. LZ belongs to group II, whereas the JY strain is a Group III virus. This is the first report on the isolation of a Group III virus in China. The detection of selective pressures on the PPV genome shows that the NS1 and VP2 genes are under purifying selection and positive selection, respectively. Moreover, the amino acids in the VP2 capsid are highly variable because of the positive selection.
  
  
  CONCLUSIONS
  Our study provides new molecular data on PPV strains in China, and emphasizes the importance of etiological studies of PPV in pigs.
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Sciences, Lanzhou, Gansu 730046, PR China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Hao
authors.forename: Zengjun
authors.initials: Z
authors.lastname: Lu
authors.forename: Pu
authors.initials: P
authors.lastname: Sun
authors.forename: Yuanfang
authors.initials: Y
authors.lastname: Fu
authors.forename: Yimei
authors.initials: Y
authors.lastname: Cao
authors.forename: Pinghua
authors.initials: P
authors.lastname: Li
authors.forename: Xingwen
authors.initials: X
authors.lastname: Bai
authors.forename: Huifang
authors.initials: H
authors.lastname: Bao
authors.forename: Baoxia
authors.initials: B
authors.lastname: Xie
authors.forename: Yingli
authors.initials: Y
authors.lastname: Chen
authors.forename: Dong
authors.initials: D
authors.lastname: Li
authors.forename: Zaixin
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000818:Animals; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D005838:Genotype; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010322:Parvoviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D028323:Parvovirus, Porcine / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology* / Q000821:virology*
chemical_list: D004279:DNA, Viral