Use of automated real-time reverse transcription-polymerase chain reaction (RT-PCR) to monitor experimental swine vesicular disease virus infection in pigs

Automated real-time RT-PCR was evaluated as a diagnostic tool for swine vesicular disease virus (SVDV) infection on a range of samples (vesicular epithelium, serum, nasal swabs, faeces) from four inoculated and three in-contact pigs over a period of 28 days. Traditional diagnostic procedures (virus isolation, and ELISAs for antigen and antibody) were used in parallel. Each inoculated pig developed a significant viraemia and clinical disease, and excreted virus, which was transmitted to the in-contact animals. The latter, however, developed only a short-lived, low-level viraemia and no clinical disease. The RT-PCR and virus isolation were generally comparable in detecting SVDV in the serum and nasal swabs from inoculated and in-contact pigs up to day 6 after infection; it was possible, however, to isolate virus for a longer period from the faeces of a few pigs. This suggested that further optimization of the template extraction method was required to counteract the effects of RT-PCR inhibitors in faeces. It was concluded that the automated real-time RT-PCR is a useful diagnostic method for SVD in clinically or subclinically affected pigs and contributed to the study of the pathogenesis of SVD in the pigs. (C) 2004 Elsevier Ltd. All rights reserved.