Comparative study in cattle and buffaloes for evaluation of various diagnostic tests for brucellosis

Serum samples from 1134 vaccinated and non vaccinated animals (775 cattle and 359 buffaloes) were screened with different serological tests like Rose Bengal plate Test (RBPT), plate agglutination test (PAT) and standard tube agglutination test (SAT). The agreement between these three screening tests was 87.19% and 97.86% in vaccinated and non vaccinated cattle while corresponding figures in buffaloes were 91.56% and 84.42%. Among vaccinated animals a positive percentage of 12.8 and 8.8 was noticed in cattle was 4.7 and 6.3, respectively by RBPT. All the positive sera samples were further tested by mercaptoethanol test (MET) and heat inactivation test (HIT) to conform the result of screening tests and to differentiate vaccinal titre from that of active infection. It was concluded that RBPT is overall best screening test to diagnose bovine brucellosis. MET and HIT are good supplementary tests but MET is better than HIT both in cattle and buffaloes. Some high titered non vaccinated buffaloes were negative in RBPT but positive by all other tests.