Quantitative, competitive PCR analysis of porcine circovirus DNA in serum from pigs with postweaning multisystemic wasting syndrome.
A competitive PCR (cPCR) assay was developed for monitoring porcine circovirus (PCV) DNA in serum samples from piglets. The cPCR was based on competitive coamplification of a 502- or 506-bp region of the PCV type 1 (PCV1) or PCV2 ORF2, respectively, with a known concentration of competitor DNA, which produced a 761- or 765-bp fragment, respectively. The cPCR was validated by quantification of a known amount of PCV wild-type plasmids. We also used this technique to determine PCV genome copy numbers in infected cells. Furthermore, we measured PCV DNA loads in clinical samples. More than 50% of clinically healthy piglets could harbor both types of PCV. While PCV1 was detected in only 3 of 16 pigs with postweaning multisystemic wasting syndrome (PMWS), all the sick piglets contained PCV2. A comparison of the PCV2 DNA loads of healthy and sick animals revealed a significant difference, indicating that the development of PMWS may require a certain amount of PCV2.
Liu
Q
Q
Veterinary Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E3. liuq@sask.usask.ca
Wang
L
L
Willson
P
P
Babiuk
L A
LA
D000818:Animals; D018173:Circoviridae Infections / Q000662:veterinary* / Q000821:virology; D017925:Circovirus / Q000235:genetics / Q000302:isolation & purification*; D004279:DNA, Viral / Q000097:blood*; D016679:Genome, Viral; D016133:Polymerase Chain Reaction / Q000379:methods*; D013552:Swine; D013553:Swine Diseases / Q000821:virology*; D019562:Viral Load; D019282:Wasting Syndrome / Q000662:veterinary* / Q000821:virology
D004279:DNA, Viral