ADVANCES IN DIAGNOSTIC TECHNIQUES

The application of genetic-based systems for the direct detection of viruses is discussed, with special regard to the different variants of the PCR. The group started the development of various PCR systems for routine diagnosis as early as in 1987-88. Subsequently, more than 60 PCR assays have been developed for routine diagnostic use. The first assays were classical PCR, nested-, or semi-nested PCR. Four commercial PCR kits were developed. Special instruments and laboratory practice have been introduced to avoid false positive results. False negatives are avoided by the use of internal controls of amplification (mimics). Recently, various methods of real-time PCR (TaqMan, Molecular Beacons, Primer-Probe Energy Transfer System) have been developed and are used in the routine diagnostic laboratory, i.e., for the detection and differentiation of swine vesicular virus and vesicular stomatitis virus. Multiplex PCR packages are under developed in the frame of a EC project, for the simultaneous detection of eight important viruses of swine: classical swine fever virus, African swine fever virus, porcine reproductive and respiratory syndrome virus, Aujeszky's disease virus, porcine parvovirus, swine vesicular disease virus, foot and mouth disease virus, and vesicular stomatitis virus. In order to further simplify and accelerate the work, nucleic acid extraction robot and pipetting robot are applied. Thus, PCR diagnostic procedures are rapid, robust and automated. By following the rules of the Office International des Epizooties (OIE), international consortia of laboratories are working on the five steps of validation and standardisation, including “ring tests”