Detection of classical swine fever virus in archival formalin-fixed tissues by reverse transcription-polymerase chain reaction

Classical swine fever (CSF) is an economically important Office International des Epizooties list A disease of swine. Inadequate diagnostic infrastructure in developing countries may sometimes make the conduit of viable samples to diagnostic laboratories difficult and at times formalin-fixed tissues may be the only morbid materials available which are not amenable to most laboratory tests. The potential diagnostic abilities in such situations would be enhanced if a highly sensitive and specific method as reverse transcription-polymerase chain reaction (RT-PCR) could be applied to such samples. In the present study, archival formalin-fixed CSF samples were subjected to successful RT-PCR amplification of a 172-bp fragment from E2/NS2 region of CSFV genome. The fidelity of amplification was established by a dot-blot hybridization assay employing a homologous biotinylated cDNA probe. The optimized procedure may be resorted to as a diagnostic tool if viable samples are unavailable and may have the potential to facilitate retrospective studies on archival samples.