FURTHER CHARACTERIZATION OF BORDER DISEASE VIRUS ISOLATES - EVIDENCE FOR THE PRESENCE OF MORE THAN 3 SPECIES WITHIN THE GENUS PESTIVIRUS

The molecular analysis of three ovine pestivirus strains revealed the existence of two distinct groups of sheep-derived pestiviruses, namely ''true'' border disease virus strains (BDV) and bovine viral diarrhea virus (BVDV)-like strains. As an extension of these studies RT-PCR an d nucleotide sequencing of the autoprotease (N-pro) and nucleocapsid p rotein (C) encoding regions of additional serologically defined ovine pestivirus strains were performed. A comparison of N-pro and C reveale d that three ovine isolates belong to the group of true BDV while two were clearly different from these as well as from BVDV and CSFV. The a mino acid identity between the latter two ovine strains is 85% for N-p ro and 92% for C and thus similar to values found within the three pes tivirus species defined so far. In order to allow comparison with addi tional pestiviruses the nucleotide sequences of a part of the 5' nonco ding region were determined for the ovine pestivirus strains. The comp arative analysis showed that recently described BVDV strains associate d with acute lethal infection were very similar to two ovine isolates. The latter represent a fourth group within the genus pestivirus diffe rent from the so far defined pestivirus species BVDV, true BDV, and CS FV. The data lead to the question whether the current nomenclature of pestivirus species according to the host origin and the induced diseas es is still appropriate. (C) 1995 Academic Press, Inc.