SBIR-STTR Award

Leptospirosis is considered to be the most widespread zoonotic disease in the world. Human disease is acquired primarily through contact with water contaminated with the urine of infected wild or domestic animals. Leptospirosis is recognized as an emerging infectious disease in the US, where it has caused extensive outbreaks associated with flooding and fresh water recreation. In less developed countries, leptospirosis is a major public health problem as the cause of substantial morbidity and mortality among subsistence farmers and urban slum dwellers. Because few laboratories are equipped to perform the antiquated microagglutination test upon which diagnosis now depends, it is well recognized that human leptospirosis is an under-recognized disorder. To date there is no effective prevention for leptospirosis. Leptospiral infections can be treated with inexpensive antimicrobial agents. However, timely treatment is considered to be essential to prevent disease progression to renal or hepatic failure, and/or massive pulmonary hemorrhage. The major obstacle to successful treatment is the difficulty in making an early and accurate diagnosis. The goal of the research proposed here is the development of a rapid, point-of-care diagnostic test for human leptospirosis, based upon the innovative proprietary lateral flow technology (DPP, Dual Path Platform) of the investigator organization, Chembio Diagnostic Systems Incorporated. Development of the test will be made possible by collaboration with Weill Medical College of Cornell University and the Oswaldo Cruz Foundation in Brazil - the largest research institution in Latin America. The collaborating investigators have developed unique leptospiral antigens that will be used in the proposed work. The two specific aims of the Phase I studies will result in a prototypic test and establish the feasibility of proceeding into Phase II evaluations: 1. Using a novel antigen screening method developed by Chembio (termed MAPIA); the most seroreactive antigens recognized during the acute phase of leptospirosis will be identified. 2. A combination of the most seroreactive antigens will be used to develop a prototype lateral flow diagnostic test to detect the greatest number of acute-phase patients, while avoiding antigens recognized by control subjects. The point-of-care diagnostic to be developed here could revolutionize clinical practice by allowing the first medical provider in contact with a potential patient to make an immediate diagnosis of leptospirosis and initiate treatment. Lateral flow tests are highly suitable for use in developing countries, as well as in a variety of field or community settings, because they require no equipment to use, are room temperature stable, and have long shelf lives. Furthermore, these features also make this type of test ideal for epidemiological investigations

Leptospirosis is a life-threatening zoonotic infection that causes acute renal failure and pulmonary hemorrhage. In the US, human leptospirosis is an emerging disease due to outbreaks that have occurred during disasters and sporting events and the increase in travel and recreation-related exposures. Furthermore, leptospirosis is a ""neglected"" disease which imparts it largest burden in populations of urban slum dwellers and subsistence farmers. More than one million cases of leptospirosis are reported each year, mostly from developing countries. Mortality from severe clinical forms of the disease is >10%. In several regions leptospirosis has emerged as the major cause of hemorrhagic fever. The critical need in addressing leptospirosis is a rapid diagnostic test that can enable clinicians to make effective decisions on therapy and management. Antimicrobial therapy, when administered early in the illness, can prevent disease progression and mortality. Timely diagnosis requires a laboratory test since the clinical presentation of early-phase leptospirosis is non-specific and often confused as being dengue or other cases of an acute febrile illness. Yet currently available tests have inadequate sensitivity (<50%) in detecting early-phase leptospirosis. Our Phase I studies have demonstrated the feasibility of developing a high-performing rapid test for leptospirosis. We have identified novel diagnostic targets, Leptospira immunoglobulin-like (Lig) proteins, which are the immunodominant antigens recognized by antibodies during infection. We have applied recombinant Lig fragments to an innovative proprietary immunoassay format, the Dual Path Platform (DPP""), and found that a DPP prototype had an overall sensitivity of 85% and specificity of 90% in evaluations of samples from leptospirosis patients from Brazil and Thailand. Furthermore, the DPP prototype had a sensitivity of 78% in identifying leptospirosis in the first 7 days of illness, the ""window-of- opportunity"" during which initiation of antimicrobial therapy provides greatest benefit. In this Phase II application we propose to develop and evaluate a rapid diagnostic test for leptospirosis which will have required characteristics for general use worldwide. The specific aims are to: 1) develop and optimize assay design, 2) determine diagnostic test performance in a multicenter evaluation, and 3) validate test production protocols in preparation for regulatory approval. We expect that a developed and fully validated assay will have major beneficial consequences for clinical practices worldwide by allowing physicians to make a point-of-care diagnosis and initiate timely therapeutic interventions which are required to prevent the high mortality associated with leptospirosis.

Public Health Relevance:
There is no effective prevention for human leptospirosis, a life-threatening emerging zoonotic disease, whose global burden is estimated to be as high as 500,000 cases annually. Untreated leptospirosis often progresses to multi-organ failure and/or pulmonary hemorrhage, and prompt diagnosis and early initiation of antibiotic therapy are the key intervention to prevent the morbidity and mortality associated with these complications. The research proposed here aims to develop a rapid point-of-care diagnostic test for leptospirosis which would enable antibiotic therapy to be initiated during the acute phase of the infection, when it is most effective. As part of the proposed Phase II study, we will conduct clinical evaluations of the rapid diagnostic test in preparation for regulatory approval.

Thesaurus Terms:
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