Diagnostic validation of ovine and caprine brucellosis using serum- and milk-ELISA.

AIM To introduce and validate the new method of diagnosing ovine and caprine brucellosis in a rapid, accurate and inexpensive manner by using i-ELISA (serum/milk) technique. METHODS Serum and milk samples from brucella RB and CFT negative (n=881) and positive (n=755) animals were used. Standardization of tests was through the Bommeli ELISA-BESW (Brucella Bang) standard and our Institute's (MKD) working standards (positive serum and milk based on B. melitensis antigen). RESULTS Validation of serum/milk ELISA for detecting ovine and caprine brucellosis was completed. The specificity obtained for the serum ELISA was 99.0% for the Bommeli system (at cut-off of 30% of positivity--PP) and 99.4% for the MKD system (at cut-off 15% PP). The sensitivities of serum ELISAs at the same cut-off were 98.5% for the Bommeli and 96.6% for the MKD test. Parallel milk samples from the same animals showed a specificity of 99.5% in the Bommeli system (at cut-of 30% PP) and 99.8% in the MKD system (at cut-off 25% PP). The sensitivity of the milk ELISAs were 94.6% for the Bommeli test and 95.6% for the MKD test. CONCLUSION The Bommeli ELISA and MKD ELISA were successfully standardized and validated as confirmatory tests for the diagnosis of B. melitensis in sheep and goat samples (milk/sera). Using our Institute's milk standard, we confirmed successful screening of brucellosis in pooled milk samples from 100 sheep and 100 goats.