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Differential detection of swine vesicular disease virus (SVDV) from the other vesicular disease viruses of foot-and-mouth disease (FMD), vesicular stomatitis (VS) and vesivirus is important as the vesicular lesions produced by these viruses are indistinguishable in pigs. Two independent sets of primers and probe, designed from nucleotide sequences within the 5′ untranslated region (UTR) of the SVDV genome, were evaluated in a real-time (5′ nuclease probe-based or fluorogenic) PCR format. Although both primers/probe sets failed to detect one isolate, the assays successfully amplified RNA extracted from epithelial suspensions (ES) and cell culture grown virus preparations from clinical samples representing all currently designated phylogenetic groups of SVDV. Furthermore, no cross-reactivity was demonstrated when these primer/probe sets were tested with RNA prepared from all seven serotypes of FMD virus (FMDV) and from selected isolates of VS virus (VSV), vesivirus and teschoviruses. These assays provide sensitive and rapid alternatives to supplement the routine procedures of ELISA and virus isolation for SVDV diagnosis. The two independent sets of primers/probe can be used routinely while only one of the primers/probe sets would typically be used in SVDV diagnosis during an outbreak. [Copyright &y& Elsevier]

A fluorogenic RT-PCR (5′-nuclease probe-based) assay using a primer/probe set designed from the internal ribosomal entry site region of the virus genome was developed for the specific detection of all seven serotypes of foot-and-mouth disease (FMD) virus in epithelial suspensions and cell culture virus preparations. The reverse transcription polymerase chain reaction (RT-PCR) specifically detected FMD virus in sample submissions from the UK 2001 FMD outbreak with greater sensitivity than our conventional RT-PCR procedure and our routine diagnostic procedures of ELISA and virus isolation in cell culture. The fluorogenic RT-PCR provides relatively fast results, enables a quantitative assessment to be made of virus amounts and can handle more samples and/or replicates of samples in a single assay than the conventional RT-PCR procedure. Therefore it is seen as a valuable tool to complement the routine diagnostic procedures for FMD virus diagnosis. [Copyright &y& Elsevier]

Automated fluorogenic (5′ nuclease probe-based) reverse transcription polymerase chain reaction (RT-PCR) procedures were evaluated for the diagnosis of foot-and-mouth disease (FMD) using suspensions of vesicular epithelium, heparinised or clotted blood, milk and oesophageal-pharyngeal fluid (‘probang’) samples from the United Kingdom (UK) 2001 epidemic and on sera from animals experimentally infected with the outbreak serotype O FMD virus strain. A MagNA Pure LC was initially programmed to automate the nucleic acid extraction and RT procedures with the PCR amplification carried out manually by fluorogenic assay in a GeneAmp® 5700 Sequence Detection System. This allowed 32 samples to be tested by one person in a typical working day or 64 samples by two people within 10–12 h. The PCR amplification was later automated and a protocol developed for one person to complete a single test incorporating 96 RT-PCR results within 2 working days or for two people to do the same thing in around 12 h. The RT-PCR results were directly compared with those obtained by the routine diagnostic tests of ELISA and virus isolation in cell culture. The results on blood, probang and milk samples were in broad agreement between the three procedures but specific RT-PCR protocols for such material have to be fully optimised as perhaps have the positive-negative acceptance criteria. However, the automated RT-PCR achieved definitive diagnostic results (positive or negative) on supernatant fluids from first passage inoculated cell cultures and its sensitivity was greater than ELISA on suspensions of vesicular epithelium (ES) and at least equivalent to that of virus isolation in cell culture. The combined tests of ELISA, virus isolation in cell culture and RT-PCR might, therefore, only be required for confirmation of a first outbreak of FMD in a previously FMD-free country. Should a prolonged outbreak subsequently occur, then either ELISA plus RT-PCR or else RT-PCR alone could be used as the laboratory diagnostic tool(s). Either approach would eliminate the requirement for sample passage in cell culture and considerably advance the issue of laboratory diagnostic test results. [Copyright &y& Elsevier]