Submitted to: Veterinary Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/3/2005
Publication Date: 11/2/2005
Citation: Fulton, R.W., Ridpath, J.F., Ore, S., Confer, A.W., Saliki, J.T., Burge, L.J., Payton, M.E. 2005. Bovine viral diarrhoea virus (BVDV) subgenotypes in diagnostic laboratory accessions: distribution of BVDV1a, 1b, and 2a subgenotypes. Veterinary Microbiology. 111:35-40. Interpretive Summary: Bovine viral diarrhea virus (BVDV) is the most economically important viral pathogen of cattle in the U.S. Voluntary control programs are currently being designed to reduce the incidence of BVDV infections. Basic information regarding incidence, variation among BVDV and disease syndromes associated with BVDV infections is necessary to the design of these programs. The purpose of this study was provide such basic information by characterizing BVDV isolated from submissions to a large regional diagnostic laboratory in the Southwestern U.S. It was found that the most frequently noted syndromes were respiratory disease and persistent infections although digestive disorders and abortions were also reported. A lot of variation was noted among the 131 viruses examined. All 131 viruses could be assigned to one of three different groups, which are referred to as genotypes. In the U.S. most vaccines contain viruses from a subgenotype called BVDV1a. One of the most significant findings of this study is that most of the viruses examined belonged to the subgenotype BVDV1b. These results suggest that the current vaccines do not contain viral strains that are representative of the viral strains that are causing most of the BVDV associated disease.
Technical Abstract: The prevalence of bovine viral diarrhea virus (BVDV) subgenotypes and biotypes was determined from 131 BVDV positive samples submitted to a diagnostic laboratory in the Southwestern U.S. Samples were collected from both live animals and at necropsy. The BVDV isolated were segregated into three subgenotypes by differential PCR and phylogenetic analysis based on comparison of the 5’ untranslated region (5’ UTR). These samples contained 117 noncytopathic (NCP) and 11 cytopathic (CP) BVDV. There were three samples that contained viruses from both the NCP and CP biotypes. Segregation by subgenotype revealed that 60 (45.8%) of the isolated BVDV belonged to the BVDV1b subgenotype. Of the remaining isolates 37 (28.2%) belonged to the BVDV1a subgenotype and 34 (26.0%) belonged to the BVDV2a subgenotype. The clinical presentation included respiratory disease, enteric disease, abortion, multiple organ involvement and persistent infections. The most frequent clinical presentations noted in submission were respiratory disease and persistent infection. There was no correlation between subgenotype and clinical presentation. All of the 131 viruses, except one, were genetically distinct from strains present in U.S. vaccines