Genetic evolution and phylogenetic analysis of porcine circovirus type 2 infections in southern China from 2011 to 2012

Porcine circovirus type 2 (PCV2), the primary causative agent of porcine circovirus-associated diseases (PCVADs), is a serious economic problem for the swine industry worldwide. Three major PCV2 genotypes (PCV2a, PCV2b, and PCV2c), have been identified. To explore the prevalence of different subgroups of PCV2 in southern China, 66 PCV2 isolates collected during 2011-2012 were analyzed. PCV2b was the predominant genotype circulating in southern China from 2011 to 2012. Moreover, subtype 1C was the predominant subtype. Comparisons of the complete ORF2 nucleotide sequence revealed 89.3-100% homology and 87.2-100% amino acid sequence identities. The deletion at position 1042 and two nucleotide substitutions at positions T1035A or T1033C were important for the PCV2 evolution. Base-by-base of ORF2 comparison showed that the PCV2 evolution trace was PCV2a to PCV2b-1A1B to PCV2b-1C. These results contribute to the understanding of PCV2 epidemiology in southern China. (c) 2013 Elsevier B.V. All rights reserved.