COMPARATIVE-STUDY OF A BLOCKING ENZYME-LINKED-IMMUNOSORBENT-ASSAY ANDTHE IMMUNOPEROXIDASE MONOLAYER ASSAY FOR THE DETECTION OF ANTIBODIES TO THE PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS IN PIGS

A blocking enzyme-linked immunosorbent assay (ELISA) for detecting ant ibodies to the porcine reproductive and respiratory syndrome virus (PR RSV) in pig sera was developed and compared with the immunoperoxidase monolayer assay (IPMA), the most widely used serological diagnostic te st in Europe. The blocking ELISA was specific and more sensitive than the IPMA when applied to field sera and to sera which were collected e arly after an experimental infection with PRRSV. Problems with high ba ckground activity as observed in IPMA or indirect ELISA were not encou ntered.