Development of an Immunodiagnostic Test for Screening Human Brucellosis Cases Using the Whole-Cell Antigens of Brucella abortus

Abstract

Background: Human brucellosis is an important zoonotic disease of public health and often remains neglected owing to lack of sensitive and efficient diagnostic methods. This study evaluates diagnostic utility of in-house designed enzyme-linked immunosorbent assay (ELISA) using whole-cell antigens of Brucella abortus (B. abortus) S19 against the commercially available kits. Methods: A prospective cohort study involving different populations within the Vidarbha regions of Maharashtra, India was conducted through camps organised from May 2009 to October 2015. A total of 568 serum samples were collected from high-risk people recruited as study cohorts based on inclusion criteria, additional risk factors and clinical symptoms. Samples were evaluated by indirect ELISA using the whole-cell antigens of B. abortus. The results were compared with the commercially available IgG detection ELISA kit to ascertain the specificity and sensitivity of the developed test. Results: Fever, body ache, joint pain, lower back pain, loss of appetite and weight loss were major symptoms associated with the disease. With the cut-off of > 0.8, the positivity of brucellosis infection was at 12.32% (70/568) compared to 9.33% (53/568) as detected by the commercial kit. The in-house developed ELISA method yielded a sensitivity of 87.5% and specificity of 99.18% as compared to the commercial kits (sensitivity –80.30% and specificity –99.6%). Discussion: The B. abortus S19-derived whole-cell protein-based ELISA is rapid and cost- effective and can be used for screening brucellosis infection in lieu of the commercially available ELISA kits.