Evidence for the presence of two novel pestivirus species

The genus Pestivirus of the family Flaviviridae comprises four species, nam ely Bovine viral diarrhea virus-1 (BVDV-1), BVDV-2, Border disease virus (B DV), and Classical swine fever virus (CSFV). Comparative analyses of partia l sequences have suggested that pestivirus isolates from giraffe (Giraffe-1 ) and reindeer (Reindeer-1) are distinct from the established species (Bech er et al., Virology 262, 64-71, 1999). In this study, we report the complet e genomic sequences of pest[virus strains Giraffe-1 and Reindeer-1. Compara tive sequence analyses revealed considerable differences among Giraffe-1, R eindeer-1, and the currently recognized pestivirus species. Phylogenetic an alysis of the complete coding sequences of these two strains, along with 13 other sequences representing the four established species, indicated that CSFV BDV, and Reindeer-1 have bifurcated from one common branch and BVDV-1 and BVDV-2 from another. In the former branch BDV and the pestivirus from r eindeer are more similar to each other than to CSFV. The giraffe pestivirus is equally distinct from both major branches. In addition, the antigenic r elatedness of pestivirus isolates covering the observed major genetic group s was studied by cross-neutralization assays. A clustering procedure on the basis of antigenic differences indicated the presence of six major groups corresponding to the genetically defined groups, Taken together, the result s of our analyses addressing both nucleotide sequence relatedness and serol ogical relatedness argue for the inclusion of Giraffe-1 and Reindeer-1 as t he first members of two separate novel species within the genus Pestivirus. (C) 2001 Academic Press.