Development and validation of a competitive ELISA kit for the serological diagnosis of ovine, caprine and bovine brucellosis.

A competitive ELISA (Brucella-Ab c-ELISA) was standardized and validated for the detection of Brucella antibodies in cattle, sheep and goat sera using a monoclonal antibody (MAb 4B5A) produced against Brucella melitensis biotype 2. The specificity and sensitivity of the assay were 100% to a 67.5% cut-off point (B/Bo%). When compared with an indirect ELISA, the Brucella-Ab c-ELISA did not demonstrate cross-reactions when testing positive sera for antibodies to some Enterobacteriaceae. A comparison was made between the Brucella-Ab c-ELISA and the complement fixation and Rose Bengal tests. Results demonstrated that the Brucella-Ab c-ELISA is a valuable tool for the serological diagnosis of bovine and ovine/caprine brucellosis.