Diagnostic assays applied in BVDV control in The Netherlands

In The Netherlands, a voluntary bovine virus diarrhoea virus (BVDV)-free certification programme was started in 1997. After an intake procedure in which all cattle are tested for the presence of BVD virus, a herd obtains the status “BVD-virus-free”. To maintain this status a monitoring procedure is executed to verify absence of BVDV circulation in the herd. Several diagnostic tests are used: RT-PCR in bulk milk and pooled blood samples, antigen-ELISA (Ag-ELISA) and antibody ELISA in individual blood samples. Sensitivity and specificity of these tests are discussed. In addition, a diagnostic quick scan has been introduced, consisting of a combination of bulk milk tests for virus and antibody, and antibody tests in samples from young stock. Preliminary results are presented.