Pestivirus bovis Species Taxonomy and Genomic Sequence Characteristics

Abstract

Pestivirus bovis viruses are pathogens of bovines and other domestic and wild ruminant species, causing economic losses on zootechnics. Investigations on genetic characteristics are required to clarify the epidemiology of the species genotypes and to elucidate specific aspects at molecular level, such as the ways of diffusion, transmissibility, virulence or mechanisms to escape host defense. In order to study the taxonomy of the species, with particular focus on genotype b, deposited 5'-UTR and Npro sequences of strains have been evaluated by the primary and secondary structure analysis, by comparison with molecular characteristics of previously reported virus isolates in the genus Pestivirus . The strains were clustered into genotypes and sub genotypes, showing the heterogeneity of the P. bovis species. In relation to geographic distribution, genotype b resulted in a cosmopolitan distribution. Other genomic clusters were related to restricted regions. Genotype b showed a wider host spectrum, in contrast to the other groups. Cattle were the most common host in all the genotypes of the P. bovis species. The application of genetic characterization methods is essential to clarify the taxonomical status of strains and should not be limited to a single procedure or the evaluation of primary sequence structure, especially of highly variable parts of the genome. The analysis of the secondary structure of relevant genomic sequences may help to discriminate atypical and genetically different clusters. Furthermore, information obtained by molecular investigations provides essential elements on circulating virus populations and their distribution in animal hosts, with direct implications on control and prophylaxis strategies. The occurrence of P. bovis sub genotype b2 in mosquitoes deserves particular attention. Other investigations will be necessary to confirm the phenomenon and understand its extent, which has the potential to exponentially enhance the diffusion of the virus.