Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 11, 1995
Publication Date: N/A
Interpretive Summary: Vaccines against bovine viral diarrhea virus (BVDV), in which the virus is killed, do not provide long-term protection from disease. In earlier studies, we have shown that one of the reasons for this failure is variation BVDV. Previously, it was thought that all BVDV belonged to a single group. We demonstrated that they belong to at least two groups and that viruses from the two groups differ in the severity of disease they cause. Further, animals protected from infection by one group may not be protected from infection by the other group. All of the studies characterizing BVDV, to date, have used viruses from only one of the groups. In this report, we characterized the genetic material of a virus from the other BVDV group. We found that the genetic material of this virus was surprisingly different from the genetic material of viruses from the other BVDV group. In addition, we found a type of alteration in the genetic material of this virus that we had never seen in viruses from the other BVDV group. This information will be used to develop better vaccines and tests for BVDV. It will also be useful to scientists trying to understand why some BVDV cause severe disease and some do not.
Technical Abstract: In this study we derived the nucleic acid sequence of the large open reading frame from a virulent virus from the BVDV 2 genotype. The virus, BVDV2-890, was isolated from an animal that died of an acute uncomplicated BVDV infection. It is noncytopathic in cell culture and does not produce a p80 viral polypeptide. The ORF is 11922 nucleotide bases long and codes for 3973 amino acids. In comparison, the ORFs of other noncytopathic pestiviruses are shorter by about 250 nucleotides. The sequence identity at the amino acid level, between BVDV2-890 and published sequences for other pestiviruses, is 74% or less. The most conserved sequences between BVDV2-890 and other pestiviruses are located in the region coding for the nonstructural protein p80. The least conserved are in the regions coding for the structural gp53 and nonstructural p54 and p58 viral polypeptides. The larger size of the BVDV2-890 ORF is due to a 225 base insertion in the genomic region coding for the viral polypeptide p54. The location of this insertion was upstream from those reported in cytopathic pestiviruses and was not characteristic of all virulent BVDV 2 viruses.