Evaluation of dot-blot test for serological diagnosis of bovine brucellosis

Bastos, Carla ResendeMathias, Luis AntonioJusi, Márcia Mariza GomesSantos, Renata Ferreira dosSilva, Glaucenyra Cecília Pinheiro daAndré, Marcos RogérioMachado, Rosangela ZacariasBürger, Karina Paes

Abstract The objective of this study was to standardize and validate the dot-blot test for the serological diagnosis of bovine brucellosis, compare the results with those found in the 2-mercaptoethanol (2-ME) and complement fixation test (CF), and estimate the relative sensitivity and specificity of the dot-blot compared to these tests. Fifty bovine blood serum samples were used for the test standardization, and 1315 samples were used for evaluation and comparison between the tests; the results were compared using the Kappa indicator. At the end of standardization, it was established as optimal for the antigen obtained from Brucella abortus B19 after passing through a microorganism rupture process, the blood serum samples diluted at 1:100, and the conjugate at 1:30,000. The comparison of the dot-blot results with 2-ME showed Kappa index of 0.9939, sensitivity of 99.48%, and specificity 99.91%, with CF, Kappa index of 0.8226, sensitivity 100% and specificity 95.32%. Using the combination of the test results 2-ME and CF to establish the true condition of the animal, the dot-blot showed relative sensitivity of 100%, and relative specificity of 99.91%. The evaluated test proved to be effective and reliable, besides being easy to handle and interpret the results.

1. Animal health
2. Complement fixation test
3. 2-Mercaptoethanol
4. Brucella abortus
5. Zoonoses