DNA Microarrays as a Tool in the Investigation of Animal Viral Diseases.

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

DNA Microarrays as a Tool in the Investigation of Animal Viral Diseases.

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

Investigation into an outbreak of encephalomyelitis caused by a neuroinvasive porcine sapelovirus in the United Kingdom

An outbreak of neurological disease in grower pigs characterised by ataxia and paraparesis was investigated in this study. The outbreak occurred 3-4 weeks post weaning in grower pigs which displayed signs of spinal cord damage progressing to recumbency. Pathology in the affected spinal cords and to a lesser extent in the brainstem was characterised by pronounced inflammation and neuronophagia in the grey matter. Molecular investigation using a pan-virus microarray identified a virus related to porcine sapelovirus (PSV) in the spinal cord of the two affected pigs examined. Analysis of 802 nucleotides of the virus polymerase gene showed the highest homology with those of viruses in the genus Sapelovirus of Picornaviridae. This PSV, strain G5, shared 91-93%, 67-69% and 63% nucleotide homology with porcine, simian and avian sapeloviruses, respectively. The nucleotide homology to other members of the Picornaviridae ranged from 41% to 62%. Furthermore, viral antigen was detected and co-localised in the spinal cord lesions of affected animals by an antibody known to react with PSV. In conclusion, clinical and laboratory observations of the diseased pigs in this outbreak are consistent with PSV-G5 being the causative agent. To the best of the authors' knowledge, this is the first unequivocal report of polioencephalomyelitis in pigs by a neuroinvasive PSV in the United Kingdom