Determination of the most accurate diagnostic approach for the diagnosis of human brucellosis in Lankien, South-Sudan

Abstract

3. Objectives 3.1 Primary objective To estimate the diagnostic accuracy (sensitivity, specificity, positive and negative predicative values and likelihood ratios) of the modified RBT method and the rapid diagnostic test developed by the KIT tests performed (if commercially available) at Institute for Tropical Health (ITH), the University of Navarra, Pamplona, Spain for the diagnosis of brucellosis. Specimens collected in an endemic region (South Sudan) will be used and characterized at the ITH at the University of Navarra, Pamplona, Spain with undiluted RBT, SAT, Coombs test, Brucellacapt and when necessary an indirect ELISA used as the reference tests. 3.2 Secondary objectives • To assess the diagnostic accuracy (sensitivity, specificity, positive and negative predicative values and likelihood ratios) of the Rose Bengal test (Spinreact, Spain) at the study site. • To assess inter-user agreement of the RB test performed on site and at ITH. • To optimize the buffer used in the RBT using characterized sera available at ITH and evaluate the diagnostic performance of the modified method with serum dilution using specimens collected in this study. To date the buffer conditions are those used for diagnosis in cattle and they have not been optimized for diagnosis in humans. In fact, the conditions used in the Brucellacapt (i.e. a special buffer at pH 5.0) also render all antibodies agglutinating. Therefore, some simple modifications of the RBT conditions (i.e. pH and ionic strength) may improve the performance of RBT and produce a similarly simple but better test. • To estimate the diagnostic performance of an ‘in-house’ latex-agglutination test against Brucella-specific cytosoluble proteins. • To describe the clinical characteristics of brucellosis suspects and confirmed cases • To assess/identify risk factors for brucellosis in the study population