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

项目摘要 查加斯病由寄生虫克氏锥虫感染引起，是最普遍的寄生虫病。 在西半球，有800万至1100万人感染了这种疾病，有7000多万人处于危险之中。感染 是由拉丁美洲本地的一种昆虫媒介传播的，但也可以通过血液传播。 输血器官移植或者先天性的在短暂的急性期之后，寄生虫在体内持续多年。 感染的携带者，通常无症状，但可引起心肌病和其他病理状态 导致严重的发病率和死亡率。在美国，T. cruzi在拉丁美洲移民中很流行 这是一个未被充分认识的健康风险。媒介昆虫逐渐侵入 美国最南端的地区也增加了本土传播的威胁。恰加斯病 由于其基因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 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，但上述 这些挑战阻碍了血清学测试的准确性 三角剖分算法建立最终结果。 大多数有T.克鲁兹感染者生活在资源匮乏、不发达的地区， 病媒昆虫很难避免，但医疗保健相对原始，缺乏实验室基础设施。 由于这些原因，快速的即时检测作为诊断和治疗的工具已经变得越来越受欢迎。 南美锥虫病的流行病学监测。然而，目前这一代查加斯病快速检测方法是有限的 在灵敏度和特异性方面的次优性能，主要是由于对重组抗原的依赖 它们是某些T.克鲁兹血统，往往无法发现墨西哥和中美洲的查加斯 例迄今为止，只有一种查加斯病快速检测方法获得了FDA的批准。我们建议完成发展 一种查加斯病的快速检测方法，基于从培养的T. cruzi称TESA （锥虫排泄/分泌抗原）。我们已经开发出高产量的生产程序， 并浓缩TESA的抗原组分，使其适用于侧流测定。一期 在研究中，原型TESA快速测试已经显示出临床灵敏度和特异性接近100%， 来自拉丁美洲不同地区的一系列样本，包括墨西哥和 中美洲。在第二阶段，我们将完成TESA侧流快速测试的开发， 格式适合在低资源环境中的床旁使用。检测的临床和分析性能 将在一项涉及1,000多名恰加斯病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）申报 FDA批准TESA侧流快速试验用于查加斯病的体外诊断。

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.