DEVELOPMENT OF AN ELISA TECHNIQUE FOR SERODIAGNOSIS OF BOVINE PARATUBERCULOSIS

A local clinical Mycobacterium avium ssp. paratuberculosis (M. paratub erculosis) isolate was cultivated in large-scale culture. A procedure for efficient preparation of a lipoarabinomannan-containing antigen wa s developed and standardized; 25 mg of purified antigen were obtained per gram of bacterial wet weight. An ELISA based on this antigen was d eveloped. Intra-and interassay variation were determined to be 20% and 27%, respectively. The ELISA was evaluated using the sera of groups o f 39 non-randomly selected and 92 randomly selected animals from which ileocaecal lymphnodes were cultured to isolate viable M. paratubercul osis. Combining the results of both groups a positive predictive value of 74% and a negative predictive value of 99% were calculated. The EL ISA was licensed by the German regulatory agencies and, in a direct co mparison, was found to be superior to both other licensed assays. (C) 1997 Elsevier Science B.V.