Differential diagnosis and genetic analysis of the antigenically related swine vesicular disease virus and coxsackie viruses

Abstract

Monoclonal antibodies directed against an isolate of swine vesicular disease virus (SVDV), characterized by virus neutralization tests and competition assays, were used to compare SVDV isolates and isolates of the antigenically related Coxsackie viruses by ELISA. SVDV-specific reaction patterns and one specific for Coxsackie viruses were observed. This provided a method for distinguishing between these enteroviruses. In addition, RT-PCRs were undertaken with Coxsackie virus and SVDV genomes. Different product patterns were obtained which correlated with the genetic differences revealed by nucleotide sequence determination. RT-PCR distinguished between SVDV and Coxsackie viruses by pattern differences. Further SVDV-specific PCRs were carried out with clinical samples. Viral genomes were detected with a sensitivity equivalent to that of virus isolation in cell culture. Sequencing of the Coxsackie virus-derived 2A-coding PCR products resulted in a not previously described sequence of a B5 isolate and in SVDV-specific sequence of two Coxsackie virus A16 isolates. The differences of the isolates by ELISA and PCR reactivity, as well as the nucleotide sequence differences are consistent with the quasispecies concept of RNA viruses.