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Journal of Clinical Microbiology, December 1999, p. 3917-3924, Vol. 37, No. 12
Centre de Microbiologie et Biotechnologie,
Received 10 March 1999/Returned for modification 11 May
1999/Accepted 4 August 1999
Sets of oligonucleotide primers were designed according to the
sequences of the open reading frames (ORFs) ORF1 and ORF2 of the
prototype nonpathogenic PK-15 strain of porcine circovirus (PCV) type 1 (PCV-1). By the PCR performed with the various primer sets, genomic DNA
or RNA from other bacterial or viral pathogens of the respiratory
tracts of pigs could not be amplified. A positive amplification
reaction could be visualized with DNA extracted from a viral suspension
containing as few as 10 viral particles per ml. No DNA fragment could
be amplified from lysates of continuous porcine cell lines (PT, ST, and
PFT cells) known to be negative for PCV. When tested with clinical
samples from pigs, the results of the single PCR method showed nearly
93% (13 of 14 samples) correlation with histopathological and
immunohistochemical findings. Interestingly, subclinical PCV infections
could be detected by single PCR with clinical samples that have been
submitted from animals with irrelevant cases of respiratory and/or
enteric problems. On the basis of the nucleotide sequences of PCV
strains (PCV-2) recently associated with outbreaks of postweaning
multisystemic wasting syndrome (PWMS) in Quebec, Canada, pig farms,
other primers were designed from the PCV-1 genome, and these primers
failed to amplify genomic fragments specific to the ORF1 or ORF2 genes of clinical isolates associated with PWMS but amplified DNA from the
PCV-1 strain. Two rapid multiplex PCR (mPCR) methods have been
developed to distinguish between both genotypes of PCV. By those two
mPCR methods, (i) species-specific primer pairs were used to amplify a
DNA fragment of 488 bp specific for the ORF2 genes of both genotypes,
whereas a 375-bp fragment was amplified from the ORF1 gene of the PCV-1
strain only, or (ii) species-specific primer pairs were used to amplify
a DNA fragment of 646 bp specific for the ORF1 genes of both genotypes,
whereas a 425-bp fragment was amplified from the ORF2 gene of the PCV-1
strain only. By both mPCR methods, a PCV-2 infection was demonstrated
in tissues of 94.2% (33 of 35) of the sick pigs tested, in agreement
with previous findings showing the close association of this new
genotype of PCV with outbreaks of PMWS in Europe and North America. On the other hand, a PCV-1 infection was confirmed in only 5.7% (2 of 35)
of the pigs, and confirmation of a mixed infection with PCV-2 was
obtained by a single PCR with PCV-2-specific primers.
0095-1137/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Multiplex PCR for Detection and Typing of
Porcine Circoviruses
*
Corresponding author. Mailing address: Institut
Armand-Frappier, Centre de Microbiologie et Biotechnologie, 531 Boulevard des Prairies, Laval, Québec, Canada H7N 4Z3. Phone:
(514) 687-5010, ext. 4219. Fax: (514) 686-5627. E-mail:
Serge_Dea{at}IAF.UQUEBEC.CA.
Journal of Clinical Microbiology, December 1999, p. 3917-3924, Vol. 37, No. 12
0095-1137/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
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