Molecular identification of the vaccine strain from the inactivated bovine viral diarrhea virus (BVDV) vaccines

Since the 1980's, several kinds of inactivated bovine viral diarrhea virus (BVDV) vaccines have been used to immunize domestic animals such as cattle and goat in Korea. Immunogenicity of the BVDV vaccines has been checked by the Korean Veterinary Authority using laboratory animals. In this study, we applied a molecular method to investigate the genetic characterization of the BVDV genes in six commercial inactivated BVDV vaccines, and determined the efficiency of two extraction reagents (i.e., sodium citrate or isopropyl myristate) to separate the vaccine antigens from the antigen/adjuvant complexes. Six partial non-coding regions (288 bp) were successfully amplified with specific primer sets, which demonstrated that sodium citrate is more efficient in extracting viral RNA from inactivated gel vaccines than isopropyl myristae. In addition, we identified the virus strains from the vaccines by analyzing the nucleotide sequences of the 5' non-coding region (NCR) of BVDV. The nucleotide similarity of the partial 5' NCR ranged from 95.1 to 100% among BVDV vaccine strains, respectively, indicating that a few manufacturers used different BVDV strains to produce their vaccines.