Comparison of ELISA with Other Serological Tests in the Diagnosis of Ovine Brucellosis


Abstract: In this study,antibodies against Brucella melitensis in aborted sheep were investigated with enzyme-linked immunosorbent assay (ELISA), standard tube agglutination test (SAT), rose bengal plate test (RBPT), complement fixation test (CFT), 2-mercaptoethanol microagglutination test (2-ME-MAT)and dithiothreitol microagglutination test (DTT-MAT). The sensitivity and specificity of the tests were calculated by using CFT results as the gold standard. A Kappa value was used to measure the agreements between ELISA and the other tests. Sonicated antigen prepared from Brucella melitensis 16M strain,the peroxidase labelled anti-sheep IgG conjugate and ortho-phenylenediamine substrate were used in ELISA. A total of 500 blood samples collected from 36 sheep flocks in Elazığ and environs were examined. One hundred and three (20.6%) samples in ELISA, 55 (11%)in RBPT, 84 (16.8%)in SAT,89 (17.8%)in CFT, 79 (15.8%)in 2-ME-MAT and 81 (16.2%)in DTT- MAT were found to be brucella-positive. In the comparison of these tests,a significant difference was detected between ELISA and RBPT results (p<0.001), whereas the differences between ELISA and other tests were not statistically significant (p>0.05). Excellent agreement was detected between ELISA and CFT, DTT-MAT, 2-ME-MAT and SAT results, with kappa values of 88%, 84%, 83% and 85%, respectively. However,in the comparison of ELISA with RBPT,a kappa value of 64%(fair agreement)was obtained. In addition, the sensitivity and specificity of ELISA were determined to be 97%and 96%, respectively.

Keywords: Brucellosis, ELISA, Serological Tests, Sheep, Brucella melitensis

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