Isolation of BVDV from bovine serum by EMEA/CVMP and 9 CFR: a comparison.

Data derived from both experience and validation exercises on the behaviour and properties of BVDV is presented as applied to recovery of the virus from bovine serum used in the industrial production of animal biologicals. Licensed products both in the EU and the U.S. must use ingredients shown to be free of this agent and both regulatory agencies have published regulations governing this topic (EU: EMEA/CVMP and US: 9 CFR). The two systems differ in some specifics covering cell cultures used, timing of testing within the assays and the use of multiple approaches to the isolation of this virus. It was found that selected cell lines instead of primary cells could be used for BVDV isolation. FA tests, however, needed to be performed weekly for maximum sensitivity instead of once at the end of the test. BVDV interference assay (comparative titration) was found to be an unreliable test for the detection of non-CPE BVDV in cell culture. BVDV neutralization assays, while desirable from an informational standpoint, were determined to be unnecessary in serum that was to be adequately irradiated. Ultracentrifuge concentration of BVDV from serum was found to be a satisfactory method of increasing the sensitivity of assays for this agent, although quantification of the virus was found unnecessary in serum to be irradiated. Recommendations for the harmonization of 9 CFR and EMEA/CVMP into one assay are given.