Developing a Point-of-Care Diagnostic Assay for Leptospirosis

Leptospirosis outbreaks in US military personnel have been documented in past. Due to the high incidence of this infection in military personnel attending the Jungle Warfare School in Panama, trials of doxycycline prophylaxis and therapy were performed on this population by US Army researchers. Soldiers deploying to tropical areas of the world continue to be at risk for leptospirosis. In endemic areas leptospirosis adversely affects operations due to both the morbidity of the soldiers and the difficulty of the differential diagnosis to the medical staff. The proposed immunochromatographic test would be a useful rapid diagnostic assay for the detection of leptospirosis in deployed soldiers with fever. The objective of this topic is to develop an FDA cleared, hand held diagnostic assay which can diagnose infection of virulent Leptospira species within one week after the onset of illness with sufficient sensitivity and specificity. The assay will utilize a lateral flow (dipsticks, with or without plastic housing) chromatography that enables detection of specific IgM and/or IgG antibodies directly from blood or serum samples without processing. The development of a specific IgM detection assay to detect early antibody responses will facilitate the treatment of military personnel presenting with febrile illness. In this Phase II we will complete the selection of acute infection target antigens that detect robust IgM and early IgG responses, and finalize development of a robust field compatible detection system. The reagent and rapid assay development are already at an advanced stage of development. IgM/IgG detection will continue to be optimized and then evaluated in panels of infection confirmed sera to determine the sensitivity and specificity of the Lepto Detect assay. The ultimate performance of the assay will be at least 85% as sensitive as, and 95% as specific as current (non-deployable, non-FDA cleared) assays.