Detection of porcine enteroviruses by nRT-PCR: differentiation of CPE groups I-III with specific primer sets.
Porcine enteroviruses (PEV) comprising at least 13 serotypes grouped into three species are described as causative agents of neurological disorders, fertility disorders, and dermal lesions of swine. Despite their well-documented acid stability, enteric infection route, and similarity of clinical symptoms, most of the porcine enterovirus (PEV) serotypes are set apart from the genus Enterovirus of the Picornaviridae. Hence, PCR procedures used commonly to detect enteroviruses are not applicable to epizootic relevant PEV serotypes. A nested RT-PCR protocol is described now suited to detect all known porcine enterovirus serotypes using three sets of primer pairs. These primer pairs were designed to amplify either highly conserved sequences of the 5'-nontranslated region (5'-NTR) or the polymerase gene region of the relevant virus species. All 13 acknowledged serotypes of three PEV species and several field isolates of clinical specimens were detectable. The specificity of the PCR procedure is supported by the observation that RT-PCR-positive field isolates coincide with serological PEV classification. PEV PCR is more rapid and less laborious than the time-consuming virus isolation by tissue culture techniques over several passages and serotyping. Because other viruses such as classical swine fever virus, pseudorabies virus, porcine parvovirus, swine vesicular disease virus, and foot-and-mouth disease virus may cause diseases with similar clinical symptoms, PCR detection of all PEVs closes a diagnostic gap and offers the opportunity to use comprehensive PCR procedures for the diagnosis of all relevant viruses causing such symptoms.