Detection of two porcine circovirus type 2 genotypic groups in United States swine herds

Abstract

In late 2005, sporadic cases of an acute onset disease of high mortality were observed in 10- to 16-week-old growing pigs among several swine herds of the United States. Tissues from the affected pigs in Kansas, Iowa, and North Carolina were examined, and porcine circovirus type 2 (PCV2) was detected consistently among these tissues. Phylogenetically, PCV2 can be divided into two major genotypic groups, PCV2-group 1 and PCV2-group 2. Whereas PCV2-group 1 isolates were detected in all the diseased animals, only two of the diseased animals harbored PCV2-group 2 isolates. This observation is important because PCV2-group 1 isolates had never been reported in the United States before (GenBank as of May 16, 2006), and they are closely related to the PCV2-group 1 isolates that have been described in Europe and Asia, previously. Our analysis revealed that each genotypic group contains a distinct stretch of nucleotide or amino acid sequence that may serve as a signature motif for PCV2-group 1 or PCV2-group 2 isolates.

Genetic Diversity of Porcine Circovirus Type 2 in Korean Pigs with Postweaning Multisystemic Wasting Syndrome during 2005-2007

“…1). The comparison of nucleotide and amino acid sequences of the ORF2 gene between the Korean and other PCV2, which are known to be hypervariable and to be suitable phylogenetic marker [7,13,18,19], supported immediately above results (data not shown). Our results are consistent with those reported in the literature [6,11,23], in which group 1 PCV2 have become the dominant strains particularly subgroup 1A/B.…”

“…Since PMWS was initially described in Western Canada, incidences of PMWS and PCV2 infection have been reported in many countries of Europe, America and Asia, and PMWS is nowadays considered a very significant disease in swine industry [3,4,7,13,18,24,30]. In Korea, first PCV2 infection was diagnosed in weaned pigs with PMWS by immunohistochemistry and PCR [10].…”

“…It was reported that PCV2 can be divided into two groups based on the ORF2 sequences at nucleotides 1486-1472 of group 1 PCV2 and 1487-1473 of group 2 PCV2 and amino acids 86-91 [7], and can be further subdivided into 1A/B (PR), 1C (PL) and group 2 (KI) based on the amino acid positions 88-89 of ORF2 [6]. In this study, at amino acid positions 88-89 of ORF2 gene, 50 Korean PCV2 were found to belong phylogenetically to group 1 PCV2 with amino acids PR and PL, which is consistent with that of subgroups 1A/B and 1C PCV2.…”

Singular PCV2a or PCV2b infection results in apoptosis of hepatocytes in clinically affected gnotobiotic pigs

“…Control pigs (n = 4) were inoculated with 1 ml PCV2-free cell culture medium. The remaining pigs were either inoculated with 1 ml of PCV2a strain DQ629114 (Cheung et al, 2007) at a dose of 10…”

“…-10 À4 TCID 50 /ml (PCV2a, n = 16) or with 1 ml of PCV2b strain DQ629115 (Cheung et al, 2007) at a dose of 10 À2 -10 À4 TCID 50 /ml (PCV2b, n = 28). The infectious dose of the inocula was determined by IHC as previously described (Cheung, 2003).…”