title: Genetic variation and phylogenetic analysis of porcine circovirus type 2 infections in central China.
abstract: Porcine circovirus type 2 (PCV2) infection causes postweaning multisystemic wasting syndrome and porcine circovirus-associated diseases in many regions. A total of 77 sequences, including 31 sampled from Henan province of China, were retrieved from GenBank and subjected to amino acid variation and phylogenetic analyses. The two PCV genotypes prevailing in Henan were PCV-2a and PCV-2b with PCV-2b accounting for 93.5 % (29/31) of the Henan isolates. The 31 Henan isolates all shared between 92.7 and 100 % sequence similarity. Amino acid variation analysis of the capsid protein revealed that Henan PCV2 strains tended to accumulate more substitutions within epitopic regions-a substitution pattern consistent with host immune system-mediated selection of virus immune escape variants. The analysed PCV sequences carry evidence of at least six unique recombination events. Selective pressure analysis of the relative recombination-free ORF2 sequences of these viruses revealed evidence of sites that are likely evolving in response to host-driven immune pressures-a finding that coupled with information on the prevalent diversity in Henan PCV2 isolates of known immunoreactive genomic loci will aid in future studies aiming to assess the evolutionary responses of PCV2 in China to the widespread deployment of anti-PCV vaccines in the country.
authors: College of Animal Science and Veterinary Medicine, Henan Agricultural University, No. 95 Wenhua Road, Zhengzhou, China.
authors: Chunlong
authors: C
authors: Mu
authors: Qingyuan
authors: Q
authors: Yang
authors: Yina
authors: Y
authors: Zhang
authors: Yonghui
authors: Y
authors: Zhou
authors: Jixi
authors: J
authors: Zhang
authors: Darren P
authors: DP
authors: Martin
authors: Pingan
authors: P
authors: Xia
authors: Baoan
authors: B
authors: Cui
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D036022:Capsid Proteins / Q000235:genetics; D002681:China; D017925:Circovirus / Q000145:classification* / Q000235:genetics* / Q000472:pathogenicity; D004279:DNA, Viral / Q000235:genetics; D019143:Evolution, Molecular; D014644:Genetic Variation; D059646:Genome Size; D016679:Genome, Viral; D005838:Genotype; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D011995:Recombination, Genetic; D012641:Selection, Genetic; D012689:Sequence Homology, Nucleic Acid; D013552:Swine / Q000821:virology
chemical_list: D036022:Capsid Proteins; D004279:DNA, Viral