DIFFERENTIATION OF CLASSICAL SWINE FEVER VIRUS FROM RUMINANT PESTIVIRUSES BY REVERSE TRANSCRIPTION AND POLYMERASE CHAIN-REACTION (RT-PCR)

A reverse transcriptase-polymerase chain reaction (RT-PCR) assay was d esigned to allow the differentiation of pestiviruses by the expected s ize of the amplified fragments, One oligonucleotide primer, conserved amongst pestiviruses, and two others specific for either classical swi ne fever virus (CSFV) or bovine viral diarrhea virus (BVDV), were desi gned from the 5' non-coding region of the genome. CSFV infected cultur es (10 strains) amplified a fragment of an expected size of 200 bp; BV DV cultures (23 strains) or border disease virus (BDV) (2 strains) amp lified a fragment of an expected size of 260 bp. The specificity of th e amplified fragments was confirmed by restriction enzyme analysis, Th e threshold of sensitivity was 100 TCID50 for CSFV and 1 TCID50 for BV DV. The RT-PCR described here provides a rapid and sensitive diagnosti c tool for the detection and differentiation of CSFV from ruminant pes tiviruses.