Phylogenetic characterization of porcine circovirus type 2 in PMWS and PDNS Korean pigs between 1999 and 2006

Porcine circovirus type 2 (PCV2) has been associated with several disease outcomes in swine, primarily postweaning multisystemic wasting syndrome (PMWS) and porcine dermatitis nephropathy syndrome (PDNS). Over an 8-year period (1999–2006), we detected 36 PCV2 strains from PMWS and PDNS cases. Complete genes of the detected PCV2 strains were sequenced and analyzed. The sequences encoding a putative capsid protein, ORF2, of 233 PCV2 strains, isolated in Korea and throughout the world, could be divided into two groups (1 and 2) by phylogenetic tree analysis and multiple alignments of nucleotide sequences. Group 1 has the sequence CCCCG/TC and group 2 has the sequence AAAATC at nucleotides 262–267 of ORF2. Group 1 has PR/L and 2 has KI at amino-acid positions 88–89 of ORF2. Of the 233 PCV2 strains, 153 (65.7%) were placed in group 1 and 80 (34.4%) were in group 2 by phylogenetic characterization analysis using CLUSTER X 1.83, Puzzle 5.2, and PHYLIP 3.66 software package. Geographical analysis showed that PCV2 strains detected from the Netherlands, Thailand, and the United Kingdom were included in group 1. In contrast, PCV2 isolates from Japan, Canada, Spain, Taiwan, and South Africa belonged to group 2. Both groups were found in isolates from Korea, France, Hungary, Austria, Germany, Brazil, and the United States. Pathogenic analysis showed that PCV2 isolates from healthy pigs and from PDNS cases also fell into the two groups. PCV2 isolates from PMWS cases induced by PCV2 alone also fell into both groups.