Recent progress in the diagnosis of brucellosis.

Progress since 1975 in the development of methods for the diagnosis of brucellosis is summarized. Standard serological diagnosis improved with increased use of acidified antigen agglutination and complement fixation tests. Immunoassays, tests based on the lysis of lipopolysaccharide coated erythrocytes and tests using new antigens have increased the sensitivity and specificity of serological results. The field of cellular immunology has seen the development and field evaluation of a skin test using refined antigens and the assessment of in vitro assays of cellular activity using purified protein and crude brucella antigens. Potential diagnostic uses of these methods are discussed. Bacteriological procedures were improved by introduction of stomachers and improved culture media. The isolation of new Brucella phages and development of a thin layer chromatography method for the determination of oxidation metabolic profiles were advanced in the characterization of Brucellae. Progress was also made in the development of immunoassays for the detection of Brucella antigens in host tissues. The selection of control groups, quality control studies and problems of standardization are areas that require greater attention in future methods development work. Major achievements of the period were 1) demonstrations that diagnosis sensitivity can be increased by new assays for antibody and cellular responses, 2) new methods to discriminate between anti-Brucella abortus and anti-Yersinia enterocolitica 0:9 responses, 3) a radial immunodiffusion test that detects most actively infected cattle, and 4) the simplification and extension of oxidative metabolic and phage typing tests. Advances in clinical microbiology and molecular biology have created new opportunities to improve diagnostic methods in the next decade.