Evaluation of newly developed immunoperoxidase monolayer assays for detection of antibodies against bovine herpesvirus 4.

This study describes the evaluation of immunoperoxidase monolayer assays (IPMAs) for detection of antibodies against bovine herpesvirus 4 (BHV4) DN-599 or BHV4 LVR 140 in sera of cattle. We compared the quality of these IPMAs with the quality of a BHV4 indirect enzyme-linked immunosorbent assay (ELISA). In addition, a preliminary serological survey of BHV4 antibodies was carried out to estimate the seroprevalence of BHV4 in Dutch cattle at different ages. The specificities of both BHV4 IPMAs were 1.00. The geometrical mean titers (detection limit) of the BHV4 IPMAs were twice as high as that of the BHV4 indirect ELISA. In experimentally infected cattle, BHV4 antibodies were detectable by IPMAs 16 to 18 days postinfection, which was almost 2 weeks earlier than in the indirect ELISA. The reproducibility of the BHV4 DN-599 IPMA (kappaD value, 0.92) and of the BHV4 LVR 140 IPMA (kappaD value, 0.87) were good. For field sera the overall agreement between the BHV4 indirect ELISA and the two BHV4 IPMAs, DN-599 and LVR 140, was 95 and 96%, respectively. The serological-survey study showed that the estimated seroprevalence of BHV4 in Dutch cattle was 16 to 18% and that the percentage of BHV4-positive animals varied by age category (between 6 and 43%). In summary, the two BHV4 IPMA formats have several advantages that make IPMA a useful alternative to the BHV4 indirect ELISA for detecting BHV4 antibodies in cattle.