Phylogenetic analysis of 32 porcine circovirus type 2 isolates from Shandong, China

Porcine circovirus type 2 (PCV2), the essential causative agent of postweaning multisystemic wasting syndrome (PMWS), can be divided into distinct genotypes. Thirty-two PCV2 isolates obtained made from pigs in Shandong Province between 2005 and 2013. Complete genome sequences were obtained in three replicates for each virus isolate, and the sequences were submitted to the NCBI database. The ORF1-encoded amino acid sequences had 98.4 %–100 % identity among the 32 isolates, and there were no significant differences among the three potential glycosylation positions: aa 23–25 (NPS), aa 256–258 (NQT) and aa 286–288 (NAT). The amino acid sequences of ORF2 had 88 %–100 % identity among the 32 isolates and the potential glycosylation position in the cap protein, aa 143–145 (NYS), had no variation. Phylogenetic analysis revealed that the PCV2b/1C genetic lineage was prevalent in swine populations in Shandong Province. It also suggested that selection pressure has made the PCV2 isolates more genetically distant from current vaccine strains.