Quantitation of porcine circovirus type 2 isolated from serum/plasma and tissue samples of healthy pigs and pigs with postweaning multisystemic wasting syndrome using a TaqMan-based real-time PCR.
Porcine circovirus type 2 (PCV2) has been linked to several disease syndromes during the last decade. In this context, postweaning multisystemic wasting syndrome (PMWS) has emerged as a significant disease. As most pig herds are infected with PCV2, the determination of viral load in animals may be useful in discriminating between healthy and PMWS pigs. A TaqMan-based real-time PCR for quantitation of PCV2 in serum/plasma and tissue samples was established. A standard curve was created from serial dilutions of a plasmid encoding ORF2 (cap gene) of PCV2 and used to estimate the number of viral DNA copies in the analyzed samples. Comparison of viral load in mesenteric lymph nodes and serum/plasma from healthy animals and PMWS animals showed statistical significant difference between the two groups (p < 0.01). No healthy pigs had viral load greater than 10(6) PCV2 genomes per ml serum or 500 ng tissue sample, while all clinically sick PMWS pigs had PCV2 loads above 10(7) in both serum/plasma and in tissue samples. Furthermore, the estimated viral load in tissue samples from PMWS pigs was related to the immunohistochemical findings, with especially lymph nodes, ileum, and tonsil giving both high viral load, and a high degree of staining by immunohistochemistry.
Brunborg
Inger Marit
IM
Section for Virology and Serology, National Veterinary Institute, P.O. Box 8156, N-0033 Oslo, Norway. inger-marit.brunborg@vetinst.no
Moldal
Torfinn
T
Jonassen
Christine Monceyron
CM
D000818:Animals; D018173:Circoviridae Infections / Q000175:diagnosis / Q000662:veterinary*; D017925:Circovirus / Q000235:genetics / Q000502:physiology*; D017931:DNA Primers; D007150:Immunohistochemistry / Q000662:veterinary; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D012367:RNA, Viral / Q000097:blood*; D012680:Sensitivity and Specificity; D013552:Swine; D013553:Swine Diseases / Q000821:virology*; D019914:Taq Polymerase; D019562:Viral Load; D019282:Wasting Syndrome / Q000662:veterinary* / Q000821:virology; D014886:Weaning
D017931:DNA Primers; D012367:RNA, Viral; D019914:Taq Polymerase