Evaluation of serological tests for detection of caprine antibody to Brucella melitensis

A total of 2213 goat sera were tested by the indirect enzyme immunoassay (IELISA), the competitive enzyme immunoassay (CELISA), the fluorescence polarization assay (FPA), complement fixation test (CFT) and the buffered antigen plate agglutination test (BPAT) for their antibody against Brucella melitensis. Of these, 528 blood samples collected in EDTA were tested in the field by the FPA (bFPA). In addition, 249 goat milk samples were tested by IELISA (mELISA). The serum samples were classified based on their reactivity in the BPAT and CFT. A total of 716 sera were positive while 1497 gave negative reactions in both tests. Relative to the BPAT and CFT reactivity, the sensitivity and specificity of the assays were as follows: IELISA: 96.2 and 99.7%, CELISA: 93.6 and 99.4% and FPA: 88.7 and 98.9%, respectively. The bFPA gave sensitivity and specificity values relative to the BPAT and CFT of 92.3 and 61.6% while the mELISA, based on the serum BPAT and CFT of the paired animals gave a relative sensitivity value of 90.9% and a relative specificity value of 92.4%.