Pestiviruses: a review

Pestiviruses comprise a group of economically important animal pathogens, namely hog cholera, bovine viral diarrhoea and border disease viruses. The viruses are serologically closely related and share a common host spectrum, i.e. pigs and numerous domestic and wild living ruminants. Interspecies transmissions occur frequently. Despite some common features in their natural hosts, pathogenesis of pestivirus-induced disease is complex; especially some aspects of highly fatal mucosal disease of cattle are still enigmatic. Pestiviruses are amongst the smallest enveloped single-stranded RNA viruses with an icosaeder-shaped nucleocapsid. They are currently classified as Togaviridae. However, based on recent progress in the molecular characterisation of the viruses their taxonomic real-location seems inevitable. Viral RNAs studied so far display one large open reading frame and in infected cells no subgenomic RNA is demonstrable. Structural proteins are coded for by genes located at the 5' end of the RNA. The majority of the genome codes for 2-3 nonstructural proteins. Virions are composed of a major and one minor envelope glycoprotein with molecular weights of 53 and 48 kD respectively. The core is composed of a small protein with a molecular weight of 20 kD. Analysis of viral proteins with monoclonal antibodies has yielded detailed information about the antigenic composition of both structural and nonstructural proteins.