Date of this Version
Published in Beef Research Program Progress Report, No. 4, Part 2 (May 1993)
Bovine viral diarrhea (BVO), caused by the BVO virus, has been recognized in many parts of the world and is considered to have a marked economic impact on the cattle industry. In the U.S. alone, serological surveys indicated that 60 to 80% of the cattle population have antibodies to the virus. There are many strains of bovine viral diarrhea virus (BVOV) which differ in their ability to cause changes in cell culture. Thus, cytopathic and noncytopathic biotypes of BVOV are identified. The cytopathic strains induce a vacuolation of the infected cultured cells, where noncytopathic strains do not. Control of BVOV has been attempted for many years by use of either modified-live or killed virus vaccines. The killed virus vaccine is more commonly used. The modifiedlive virus vaccine is known to cause complications during pregnancy, potentially fetopathogenic effects being a major concern. There is evidence that vaccination of persistently infected cattle with modified-live virus vaccine can result in severe mucosal disease. Oue to the ubiquitous nature of BVOV, producers may find advantages in designing BVO control procedures for a herd to be able to differentiate between cattle that 1) have received modified-live BVO virus vaccination, 2) have received killed BVO virus vaccination, or 3) were naturally infected. This study explored the potential of BVOV protein, p80, to allow differentiation of the above three conditions. The genome of an isolate of a BVOV strain has been sequenced. Encoded within the genome are at least four primary gene products (proteins): p20, gp116, p125, and p133. There is evidence that p125 polypeptide precursor gives rise to p80 polypeptide due to the breakdown of this precursor protein in cells infected with BVOV. The p80 area of the BVOV genome is well conserved in the many BVOV strains that have been isolated.