Abstract
Most current diagnostic assays are singleplex, or at most, can detect no more than a handful of targets simultaneously. There is an increasing demand in diagnostic laboratories for multiplex assays to facilitate investigation into the cause of outbreaks and in the meantime to obtain valuable epidemiological data e. g. pathotype or genotype of the viral agent. As part of this project a multiplex assay, a DNA microarray, was developed to enable the simultaneous detection and typing of two major quarantine viruses, the zoonotic lyssaviruses and classical swine fever virus (CSFV). The microarray was assessed by testing samples from experimentally infected animals with lyssa- and CSF- viruses and cell cultures infected with CSF viruses. The 7 genotypes of lyssaviruses and 10 sub-genotypes of CSFV were correctly identified to type. In a wider context, this study also aimed to assess the value of DNA microarrays in investigation of clinical syndromes, especially those in which current diagnostic assays had failed to identify a viral agent. Several such cases in terrestrial animals were investigated in this project. The microarray successfully identified for the first time an equine encephalosis virus outside Southern Africa, a new species of rotavirus in red squirrels, a porcine neurotropic sapelovirus in pigs and a parvovirus in goslings suffering from high mortality. In conclusion, this study provides supporting evidence on the application of microarrays as a versatile multiplex tool to detect and type known viruses and screen for re-emerging and novel viral pathogens in disease investigations.