Current status of sero-diagnosis of brucellosis

Brucellosis is an important bacterial zoonosis afflicting man and animals, especially in the developing countries. It not only has direct public health implications, but also poses a potential barrier in the international trade of animals and animal products. The tests used in the diagnosis of the brucellosis do not have complete agreement of results. Therefore, it is necessary to use a combination of tests during surveillance programmes rather than a single test. A number of serological tests are devised for the detection of Brucella reactors in man and animals but Rose Bengal plate agglutination test (RBPT), Standard tube agglutination test (STAT) and Enzyme linked immunosorbent assays (EIA) are more commonly used. RBPT is widely used for the diagnosis of brucellosis under farm conditions and is considered to be one of the most efficient tests in the diagnosis of the swine brucellosis. STAT quantifies total agglutinating antibodies and higher detection rates had been reported through STAT in sheep and goat. Counter-immunoelectrophoresis (CIE) has been assessed to be efficient to detect antibodies against internal cytoplasmic proteins and subsurface antigen. CFT was long regarded as the most sensitive and specific test for diagnosing brucellosis. However, comparable or greater sensitivity can now be achieved through enzyme immunoassays. Enzyme immunoassays (ELISA and dot-ELISA) are superior to all other tests in terms of specificity and sensitivity. ELISA and dot-ELISA in man are highly sensitive and specific for detection of Brucella agglutinins especially in cases of chronic brucellosis and neurobrucellosis. Dot-ELISA had been recommended as screening test for ovine and caprine brucellosis under field condition.