Evaluation of an indirect ELISA for the diagnosis of bovine brucellosis

Animal Health Unit, National Institute of Agricultural Technology (INTA), Bariloche, Argentina.

Control and eradication of bovine brucellosis is usually based on the serological detection of antibodies. In Argentina, the rose bengal test (RB) and the buffered plate antigen test (BPA) are the 2 screening tests officially recognized, whereas the 2-mercaptoethanol test (2ME) and the tube agglutination test (SAT) are the confirmatory assays currently in use. In order to improve the serological diagnosis of bovine brucellosis in Patagonia, Argentina, an indirect enzyme-linked immunosorbent assay (I-ELISA) kit distributed by the International Atomic Energy Agency was evaluated. Sera from negative nonvaccinated, negative but vaccinated, and positive animals were tested by all the above techniques. The specificity of the I-ELISA (98.9% and 97.2%) was similar to that of the BPA, RB, 2ME and complement fixation (CF) tests when used to test sera from negative nonvaccinated and negative but vaccinated animals, respectively. The sensitivity of the I-ELISA (98.7%) was higher than the BPA test (96.1%) and the CF test (95.2%). The I-ELISA kit evaluated in this study was thought to be a valuable tool for the diagnosis of bovine brucellosis in the Patagonia region where little epidemiological information is available about this disease, and where large numbers of sera should be tested to obtain such information.