Comparative efficacy of serological diagnostic methods and evaluation of polymerase chain reaction for diagnosis of bovine brucellosis

The aim of present study was to compare the diagnostic performance of the different Brucella abortus antigen based serological and molecular tests such as Rose Bengal Plate Test (RBPT), indirect enzyme linked immunosorbent assay (I-ELISA) and polymerase chain reaction (PCR). Out of 89 samples, 44 were positive by I-ELISA, 18 by RBPT and 21 by PCR. Substantial agreement was observed between PCR and I-ELISA (kappa=0.48). A slight degree of agreement was observed between RBPT and I-ELISA and PCR (kappa=0.18) and RBPT and PCR (kappa=0.11). Indirect enzyme linked immunosorbent assay detected more samples as positive among these tests. In conclusion, I-ELISA can be routinely used for an accurate and efficient diagnosis of Brucella infection, because the chances of non-detection of an infected animal in I-ELISA are minimal. However, PCR could be used as a supplement and complement test along with I-ELISA for identification and differentiation of bovine brucellosis.