Submitted to: United States Animal Health Association Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 2, 1999
Publication Date: N/A
Technical Abstract: Bovine viral diarrhea virus (BVDV) continues to have a significant impact upon US cattle producers. BVDV contamination of reagents and cell lines bedevils diagnostic laboratories, biologics producers and research facilities. Detection and control is hampered by viral heterogeneity that results in differences in neutralizing epitopes, cytopathology and virulence. To design effective programs to detect and control BVDV infections it is necessary to recognize and compensate for this heterogeneity. Phylogenetic analysis segregates BVDV into two genotypes, BVDV1 and BVDV2. A differential PCR test that distinguishes BVDV1 viruses from BVDV2 viruses has been developed. Using this test we found that the ratio of BVDV1 to BVDV2 among viruses isolated from fetal calf serum and samples submitted to diagnostic labs in the US was 2:1 and 1:1, respectively. The viral strains most commonly used in US vaccines are the BVDV1 strains NADL, Singer and C24V (a.k.a. Oregon). BVDV1 and BVDV2 are antigenically distinct from each other and BVDV2 outbreaks have occurred in herds that have been vaccinated with BVDV1. This has led to the suggestion that BVDV vaccination programs include both BVDV1 and BVDV2 vaccines. At least one commercially available vaccine contains type 2 BVDV and it is anticipated that several BVDV2 vaccines will be introduced into the market. Contamination of research reagents and veterinary biologics with BVDV usually is the result of using fetal bovine serum as a cell culture supplement. Because BVDV may infect a wide range of host cells, crosses the placenta and interacts with other pathogens to increase the severity of disease, its inadvertent inclusion in MLV vaccines poses a threat to the animal production industry.