Genetic characterization of type 2 porcine circovirus (PCV-2) from pigs with postweaning multisystemic wasting syndrome in different geographic regions of North America and development of a differential PCR-restriction fragment length polymorphism assay to detect and differentiate between infections with PCV-1 and PCV-2.
Postweaning multisystemic wasting syndrome (PMWS) is an emerging disease in swine. Increasing evidence indicates that a variant strain of porcine circovirus (PCV), designated type 2 PCV (PCV-2), is responsible for PMWS. To determine the extent of genetic heterogeneity of PCV-2 isolates, the complete genomes of six PCV-2 isolates from different regions of North America were amplified by PCR and sequenced. Sequence and phylogenetic analyses confirmed that two distinct genotypes of PCV exist: nonpathogenic genotype PCV-1 and PMWS-associated genotype PCV-2. However, within the PCV-2 genotype, several minor branches that have been identified appear to be associated with geographic origins. The genomic sequences of two French PCV-2 isolates diverge the most from those of other PCV-2 isolates and form a distinct branch. Other minor but distinguishable branches have also been identified for a Taiwan PCV-2 isolate and two of the Canadian PCV-2 isolates. All the U.S. PCV-2 isolates are closely related, but the Canadian isolates vary, to some extent, in their genomic sequences. The data from this study indicate that although the genome of PCV-2 is generally stable among different isolates, PCV-2 isolates from different geographic regions vary in their genomic sequences. This variation may have important implications for PCV-2 diagnosis and research. On the basis of genetic analyses of available PCV strains, a universal PCR-restriction fragment length polymorphism (PCR-RFLP) assay was developed to detect and differentiate between infections with PCV-1 and PCV-2. This PCR-RFLP assay should be useful for studying the pathogenesis of PCV-2, for detecting PCV-2 infection in pigs from different geographic regions, and for screening donor pigs for use in xenotransplantation.
Fenaux
M
M
Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0342, USA.
Halbur
P G
PG
Gill
M
M
Toth
T E
TE
Meng
X J
XJ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002213:Capsid / Q000737:chemistry / Q000235:genetics; D018173:Circoviridae Infections / Q000175:diagnosis / Q000662:veterinary* / Q000821:virology; D017925:Circovirus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D014644:Genetic Variation; D016679:Genome, Viral; D008969:Molecular Sequence Data; D009656:North America; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D013552:Swine; D013553:Swine Diseases / Q000175:diagnosis / Q000821:virology*; D019282:Wasting Syndrome / Q000175:diagnosis / Q000662:veterinary* / Q000821:virology