Submitted to: International Congress of Virology
Publication Type: Abstract Only
Publication Acceptance Date: August 9, 1999
Publication Date: N/A
Technical Abstract: The severity of disease caused by acute bovine viral diarrhea virus (BVDV) infection is strain-dependent and varies from clinically inapparent to highly fatal. BVDV belong to two genotypes, BVDV1 and BVDV2. Diseases resulting from BVDV1 and BVDV2 infections are frequently indistinguishable in the field. However, a clinically severe acute form of BVDV, termed hemorrhagic syndrome (HS), is only associated with BVDV2. Viruses from both genotypes may exist as one of two biotypes, cytopathic and noncytopathic. It has been shown that the cytopathic biotype in BVDV1 correlates with insertions into the viral genome. We observed a similar phenomena in cytopathic BVDV2. Surprisingly, we also found insertions in the genomes of some noncytopathic BVDV2. These insertions were seen only in noncytopathic BVDV2 that cause HS. Sequencing of the complete genomes of BVDV2 that cause HS (virulent) and BVDV2 that do not cause HS (avirulent) revealed that virulent, but not avirulent, BVDV2 have insertions into the region of the genome coding for the NS2-3 protein. Contrary to previous reports, based on a limited number of isolates, we did not find that virulence correlated with conserved motifs in the 5' untranslated region.