Rapid test for leptospirosis

描述（由申请人提供）：钩端螺旋体病是一种危及生命的人畜共患感染，可引起急性肾功能衰竭和肺出血。在美国，人类钩端螺旋体病是一种新出现的疾病，原因是在灾害和体育赛事期间发生的疫情，以及与旅行和娱乐有关的接触增加。此外，钩端螺旋体病是一种“被忽视”的疾病，给城市贫民窟居民和自给自足的农民带来了最大的负担。每年报告的钩端螺旋体病病例超过100万例，其中大多数来自发展中国家。该病严重临床形式的死亡率为10%。在一些地区，钩端螺旋体病已成为出血热的主要病因。解决钩端螺旋体病的关键需要是一种快速诊断测试，使临床医生能够对治疗和管理作出有效的决定。在疾病早期给予抗菌治疗，可预防疾病进展和死亡。及时诊断需要实验室检查，因为早期钩端螺旋体病的临床表现是非特异性的，经常被混淆为登革热或其他急性发热性疾病病例。然而，目前可用的检测方法在检测早期钩端螺旋体病方面灵敏度不足（<50%）。我们的一期研究已经证明了开发一种高效的钩端螺旋体病快速检测方法的可行性。我们已经确定了新的诊断靶点，钩端螺旋体免疫球蛋白样（Lig）蛋白，这是抗体在感染过程中识别的免疫优势抗原。我们将重组Lig片段应用于一种创新的专有免疫分析格式，即双路径平台（DPP），并发现DPP原型在评估来自巴西和泰国的钩端螺旋体病患者样本时具有85%的总体灵敏度和90%的特异性。此外，DPP原型在疾病的前7天内识别钩端螺旋体病的敏感性为78%，这是开始抗菌治疗提供最大益处的“机会之窗”。在这个II期申请中，我们建议开发和评估钩端螺旋体病的快速诊断测试，该测试将具有在全球范围内普遍使用所需的特征。具体目标是：1)开发和优化分析设计，2)确定多中心评估中的诊断测试性能，以及3)验证测试生产方案，为监管部门批准做准备。我们期望一种成熟的、完全有效的检测方法将对全世界的临床实践产生重大有益的影响，使医生能够做出即时诊断，并及时启动治疗干预措施，以防止与钩端螺旋体病相关的高死亡率。公共卫生相关性：人类钩端螺旋体病是一种危及生命的新出现的人畜共患疾病，目前尚无有效预防措施，其全球负担估计高达每年50万例。未经治疗的钩端螺旋体病经常发展为多器官功能衰竭和/或肺出血，及时诊断和早期开始抗生素治疗是预防与这些并发症相关的发病率和死亡率的关键干预措施。这里提出的研究旨在开发一种钩端螺旋体病的快速即时诊断测试，使抗生素治疗能够在感染的急性期开始，这是最有效的。作为拟议II期研究的一部分，我们将对快速诊断测试进行临床评估，为监管部门的批准做准备。

DESCRIPTION (provided by applicant): 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.