Improving diagnostic capabilities for typhoid fever

描述（由申请人提供）：目前，在世界伤寒流行地区，没有良好的伤寒（或携带）诊断测试。这一缺陷使适当抗菌药物的靶向给药复杂化，并且是伤寒控制和疫苗计划更广泛认可的主要障碍。在这两个阶段的R21（探索）/R33（扩展和开发）提案中，我们建立在持续的国际合作努力的基础上，以支持以下具体目标和里程碑：R21：第1年和第2年：创新假设驱动的项目1。抗S.伤寒伊加ALS液体检测系统作为伤寒诊断。2.尿液ELISA或试纸条测定的开发。3.筛选无症状携带者血清中针对S.伤寒抗原在体内表达，并为携带者所独有。到第2年（R21）结束时的主要里程碑，我们建议（1）至少开发一种原型方法（基于ALS或基于尿液），用于孟加拉国达卡的后续评价，以及（2）筛选携带者血液，以评估是否存在独特信号。R33：3-5年：额外的创新探索性研究和扩大诊断开发4。在孟加拉国达卡（ALS和/或尿液装置）进行R21阶段的现场（流行区）试验原型测定（如果有希望）。5.先进的携带者诊断，如果有希望的话。如果没有希望：6。进一步探索使用微流控甘露糖结合凝集素“捕获”系统来增加S.伤寒在急性感染病人的血液中。7.探讨基于γ干扰素的伤寒检测方法。8.探索诊断检测S.伤寒mRNA/cDNA（相对于gDNA）在伤寒感染的人的血液中，以提高灵敏度。到第5年年底（R33）的主要可交付成果：开发出比流行区现有检测方法更灵敏和更特异的诊断方法（我们的初步目标是灵敏度>90%;特异性>90%;比流行区现有/正在使用的检测方法有重大改进）。 公共卫生相关性：伤寒每年影响2000多万人，造成20万人死亡。有很好的伤寒疫苗，但没有好的诊断测试知道何时使用它们。开发一种良好的诊断测试将有助于使用现有的伤寒疫苗，有助于有针对性地使用适当的抗菌剂，并将改善公共卫生，每年可能挽救数万人的生命。

DESCRIPTION (provided by applicant): Currently, there is no good diagnostic test for typhoid fever (or carriage) in typhoid endemic areas of the world. This deficiency complicates the targeted administration of appropriate antimicrobials, and is a major impediment to the more widespread endorsement of typhoid control and vaccine programs. In this two-stage R21 (exploration)/R33 (expansion and development) proposal, we build upon an ongoing international collaborative effort to support the following specific aims and milestones: R21: years 1 and 2: innovative hypothesis-driven projects 1. Evaluation of anti-S. typhi IgA ALS fluid detection system as a typhoid diagnostic. 2. Development of urine ELISA or dipstick assay. 3. Screen asymptomatic carrier serum for antibodies targeting S. typhi antigens expressed in vivo and unique to the carrier state. Main milestones by the end of year 2 (R21), we propose (1) to have developed at least one prototype approach (either ALS-based or urine-based) to use in subsequent evaluations in Dhaka, Bangladesh, and (2) to have screened carrier blood to assess if a unique signal is present. R33: years 3-5: additional innovative exploratory research and expanded development of diagnostics 4. Field (endemic zone) test prototype assays in Dhaka, Bangladesh (ALS and/or urine device[s]) from R21 phase, if promising. 5. Advance carrier diagnostic, if promising. If not promising: 6. Further explore the use of a microfluidic mannose binding lectin "capture" system to increase recovery of S. typhi in the blood of acutely infected patients. 7. Explore interferon-gamma based detection assay (IGA) approach for typhoid. 8. Explore the ability to diagnostically detect S. typhi mRNA/cDNA (as opposed to gDNA) in the blood of infected humans with typhoid, to improve sensitivity. Main deliverable by the end of year 5 (R33): development of diagnostic approach(es) that is/are more sensitive and specific than current assays in an endemic zone (our initial goal will be >90% sensitivity; >90% specificity; a significant improvement over assays currently available/in use in endemic zones). PUBLIC HEALTH RELEVANCE: Typhoid fever affects over 20 million individuals per year, killing 200,000. There are good typhoid vaccines, but no good diagnostic test to know when to use them. Development of a good diagnostic test would facilitate use of currently available typhoid vaccines, assist in targeting use of appropriate antimicrobial agents, and would improve public health, potentially saving tens of thousands of lives per year.