Point-of-care diagnostic test for T. cruzi (Chagas) infection

项目摘要 恰加斯病是最流行的寄生虫，由克氏锥虫感染引起。 这种疾病在西半球蔓延，感染800万至1100万人，有7000多万人处于危险之中。感染 由一种原产于拉丁美洲的昆虫媒介传播，但也可以通过血液感染 输血、器官移植或先天的。在短暂的急性期之后，寄生虫在 受感染的携带者，通常无症状，但可引起心肌病和其他病理情况 导致严重的发病率和死亡率。在美国，克鲁兹支原体在拉美移民中很流行 在这些人群中，它构成了未被认识到的健康风险。昆虫媒介的逐渐侵入 美国最南端的地区也增加了本土传播的威胁。恰加斯病 是具有挑战性的诊断，因为它的基因类型和抗原变异的组合 地理范围、与人类宿主的复杂免疫相互作用以及与其他宿主的交叉反应 寄生虫。血清学已成为诊断的主要手段，特别是对于慢性感染，但以上 挑战阻碍了血清学检测的准确性，以至于多个检测方法通常用于 用三角剖分算法确定最终结果。 大多数有感染克鲁兹旋毛虫风险的人生活在资源匮乏、不发达地区，这些地区接触过 媒介昆虫很难避免，但医疗保健相对原始，实验室基础设施也缺乏。 由于这些原因，快速的护理点检测作为诊断和治疗的工具变得越来越受欢迎。 恰加斯病的流行病学监测。然而，当前一代的Chagas快速检测方法是有限的 在敏感性和特异性方面表现不佳，主要是由于对重组抗原的依赖 它们是特定于某些克氏锥虫血统的，通常无法检测到墨西哥和中美洲的查加 案子。到目前为止，只有一种Chagas快速检测方法获得了FDA的批准。我们建议完成开发 一种基于培养的弓形虫天然蛋白抗原的恰加斯病快速检测方法 (锥虫排泄/分泌抗原)。我们已经制定了程序，以生产高产，丰富 并浓缩TESA的抗原组分，使其适合用于侧向流动分析。在第一阶段 研究表明，原型TESA快速检测在临床上的敏感性和特异性接近100% 来自拉丁美洲流行地理的不同地区的样本范围，包括墨西哥和 中美洲。在第二阶段，我们将以符合成本效益的方式完成TESA侧向流动快速测试的开发 适用于低资源环境中的护理点使用的格式。该测试的临床和分析性能 将在现场进行的一项涉及1000多名恰加患者和对照的临床研究中进行评估 在美国和拉丁美洲的一个流行地区。临床研究结果将支持510(K)计划的提交 向FDA申请批准TESA侧向流动快速试验，用于体外诊断恰加斯病。

Project Summary Chagas disease, caused by infection with the parasite Trypanosoma cruzi, is the most prevalent parasitic disease in the western hemisphere, infecting 8-11 million individuals and with over 70 million at risk. The infection is transmitted by an insect vector that is native to Latin America, but can also be acquired through blood transfusion, organ transplant, or congenitally. Following a brief acute phase, the parasite persists for years in infected carriers, often asymptomatically, but can cause cardiomyopathy and other pathological conditions leading to severe morbidity and mortality. In the U.S., T. cruzi is prevalent in Latin American immigrant populations, where it poses an underrecognized health risk. The gradual encroachment of the insect vector into the southernmost regions of the U.S. has also raised the threat of autochthonous transmission. Chagas disease is challenging to diagnose due to the combination of genotypic and hence antigenic variation across its geographical range, complex immunological interactions with the human host, and cross-reactivities with other parasites. Serology has become the mainstay for diagnosis, especially for chronic infection, but the above challenges have hampered the accuracy of serologic tests such that multiple assays are commonly used in a triangulation algorithm to establish final results. The majority of those at risk for T. cruzi infection live in low-resource, underdeveloped areas where contact with the vector insects is hard to avoid, but medical care is relatively primitive and laboratory infrastructure is absent. For these reasons, rapid, point-of-care tests have become increasingly desirable as tools for diagnosis and epidemiological surveillance of Chagas disease. However, the current generation of Chagas rapid tests is limited by suboptimal performance, both in sensitivity and specificity, largely due to the reliance on recombinant antigens which are specific to certain T. cruzi lineages and often fail to detect Mexican and Central American Chagas cases. To date, only one Chagas rapid test has been cleared by FDA. We propose to complete development of a rapid test for Chagas disease, based on a native protein antigen from cultured T. cruzi termed TESA (Trypanosomal Excreted/Secreted Antigens). We have developed procedures to produce with high yield, enrich and concentrate the antigenic component of TESA, making it suitable for use in a lateral flow assay. In Phase I studies, the prototype TESA rapid test has shown clinical sensitivity and specificity approaching 100% across a range of samples from diverse regions spanning the endemic geography of Latin America, including Mexico and Central America. In Phase II, we will complete development of the TESA lateral flow rapid test in a cost-effective format suitable for point-of-care use in low-resource settings. The clinical and analytical performance of the test will be evaluated in a clinical study involving over 1,000 Chagas patients and controls to be carried out at sites in the U.S. and in an endemic region in Latin America. The clinical study results will support a 510(k) submission to FDA for clearance of the TESA lateral flow rapid test for in vitro diagnosis of Chagas disease.