Selection and use of laboratory diagnostic assays in BVD control programmes.

Since bovine virus diarrhoea (BVD) was recognised as a unique disease complex, many different diagnostic methods have been used to detect the BVD virus (BVDV) itself, or immunity to BVDV. Of those that have evolved along with the current demands for accurate diagnostic tests, two categories are of interest for BVD control programmes. As reference assays, virus isolation and detection of virus neutralising antibodies are both carried out using cell cultures, which are time, resource and skill demanding. Enzyme immuno-assays are better suited for screening of large series of samples, and several variants of these have been developed for detection of both antibodies and viral antigens. Of other methods adapted for rapid diagnostic use are immunohistochemistry, flow cytometry and the reverse transcription-polymerase chain reaction. Basic properties of these and other methods are reviewed, with emphasis on the need for diagnostic assays in control programmes for BVD.