Method of discrimination between vaccine type and wild type viruses of classical swine fever

One-step reverse transcriptase-polymerase chain reaction (RT-PCR) and restriction endonuclease cleavage was developed for the discrimination between the vaccine strain and wild-type viruses of classical swine fever virus (CSFV) in Korea. Based on the amplification of 5′ non-coding region of CSFV using one-step RT-PCR, followed by selective restriction endonuclease (Xho I) cleavage of the amplified DNA fragments. Vaccine strain (K-LOM) and 12 field isolates were used in this study. In all CSFV strains, the expected amplified size of 312 bp were observed. The product of wild-type viruses were cut into 225 and 87 bp with Xho I, while vaccine strain was not. The result indicate that one-step RT-PCR and restriction endonuclease assay is a useful method for distinguishing the vaccine-type from wild-types of CSFV in Korea.