New developments in the immunodiagnosis of brucellosis in livestock and wildlife

Although relatively effective diagnostic tests for brucellosis have been in existence for more than 100 years, it remains a serious, embedded and also a re-emerging disease in many parts of the globe. There are many factors besides suboptimal diagnosis that impede the complete and sustained eradication of animal brucellosis. In this review a case for the continued improvement of diagnostic methods is made through identifying existing shortcomings and considering what impact these have upon control and eradication. The focus is on developments in immunodiagnostics as these seem more likely to yield the pragmatic solutions needed. Moreover, developments in DNA detection methods have been neatly and recently reviewed elsewhere. This article reviews issues such as test cost, mobility, sensitivity and specificity. Advances in low-cost materials, high-throughput testing, assay multiplexing and the quantification of pen-side tests are described and their relevance to disease control considered. Poor test specificity when resolving positive serology, due to infection with cross-reactive bacteria and vaccination with smooth Brucella strains, is also an impediment to efficient disease eradication. A case for the development of novel discrete epitope antigens to address this is presented alongside in silico methods of selection and tools that enable increased analytical sensitivity that may be required to detect relatively low, but potentially significant, analytes. References have been drawn from the study of brucellosis wherever possible. However, in some cases new technological developments worthy of discussion have been included via the use of pertinent alternative examples. In conclusion, despite developments and innovations the classical serological tests seem under no imminent danger of mass extinction but there is potential for significant improvement and supplementation.