Enteric Pathogen Force of Infection among Children using Serology

肠道病原体感染是全球疾病负担的主要原因，负担最大的是 处于低资源环境中的儿童。基于粪便的聚合酶链式反应方法极大地提高了我们测量 肠道感染，但收集粪便的挑战和需要几乎连续的监测来检测许多 全球重要病原体阻碍了在大规模监测中的更广泛使用。大规模的，人口众多的 现在，以调查为基础的调查定期收集血液，以监测艾滋病毒、疟疾等疾病的传播和负担 还有登革热。通过多重化验对此类调查中收集的血液进行更广泛的测试是一种新的 测量肠道病原体传播和负担的机会。基于抗体的措施可以补充 基于粪便的聚合酶链式反应检测，因为抗体反应在感染后的几个月内保持高水平，因此 在不频繁测量的研究中提供更多信息。我们的团队已经开发出多重珠子 检测免疫球蛋白G(Ig G)对不同肠道病原体的反应。在初步研究中，我们 已经表明，免疫球蛋白水平可以用来衡量肠道病原体传播的异质性 人口。我们还表明，这些结果适用于跨分类群的病原体。在此应用程序中，我们 建议完成一系列研究，解决下一步推进肠道病毒血清流行病学的关键步骤 低资源环境中的病原体。我们将在厄瓜多尔进行一项纵向出生队列，配对高 解决，多重粪便为基础的聚合酶链式反应感染纵向，多重免疫球蛋白和免疫球蛋白A测定。我们的17个- 该网站一年的研究历史记录表明，在一年的时间里，肠道病原体感染存在显著差异 城乡梯度，使其成为研究的理想环境。该队列将从3名儿童中招收600名儿童 跨越城乡梯度的地点，并经常测量从出生到24个月。在Luminex上 平台，我们将在一年内将15种肠道病原体的多重PCR检测与免疫球蛋白和免疫球蛋白A的检测配对。 包括对7种肠道病原体：空肠弯曲杆菌、产肠毒素菌的抗原的多重微球试验 大肠杆菌、肠沙门氏菌、十二指肠贾第鞭毛虫、微小隐孢子虫、溶组织内阿米巴和 诺沃克病毒。在目标1中，我们将使用基于分子和抗体的方法来研究肠道感染力。 横跨城乡梯度的病原体。这将是第一次广泛的比较 预防肠道感染合并感染的血清流行病学对策。在目标2中，我们将评估肠道病原体 将当前状况模型应用于以人群为基础的横断面血清学调查 区域，并将把横断面估计值与同期的纵向估算值进行比较 学习。在目标3中，我们将研究7种病原体感染后的免疫球蛋白G和免疫球蛋白A动力学，并开发 根据横断面测量的抗体水平准确预测近期感染和发病率的模型 血清学调查。这些目标的完成将导致具有普遍意义的血清流行病学方法 在资源匮乏的环境下改变肠道病原体传播和负担的测量方法的潜力。

Enteric pathogen infections are a leading cause of the global disease burden, with the largest burden among children in low-resource settings. Stool-based PCR methods have dramatically improved our ability to measure enteric infections, but the challenge of collecting stool and need for near-continuous monitoring to detect many globally important pathogens has thwarted broader use in large-scale surveillance. Large-scale, population- based surveys now regularly collect blood to monitor transmission and burden of diseases such as HIV, malaria and dengue. Broader testing of blood collected in such surveys with multiplex assays represents a new opportunity to measure enteric pathogen transmission and burden. Antibody-based measures could complement stool-based PCR testing because antibody responses remain elevated for many months after infection, thus providing more information in studies with infrequent measurements. Our team has developed multiplex bead assays that measure immunoglobulin G (IgG) response to diverse enteric pathogens. In preliminary studies we have shown that IgG levels can be used to measure heterogeneity in enteric pathogen transmission between populations. We have also shown the results generalize to pathogens that span taxa. In this application, we propose to complete a series of studies that address key next steps to advance the seroepidemiology of enteric pathogens in low-resource settings. We will conduct a longitudinal birth cohort in Ecuador that pairs high resolution, multiplex stool-based PCR infection with longitudinal, multiplex IgG and IgA measurements. Our 17- year research history at the site has documented substantial variation in enteric pathogen infection across a rural-urban gradient, making it an ideal setting for the research. The cohort will enroll 600 children from three sites across a rural-urban gradient, and measure them frequently from birth to 24 months. On the Luminex platform, we will pair multiplex PCR assessment for 15 enteric pathogens with IgG and IgA assessment in a multiplex bead assay that includes antigens to 7 enteric pathogens: Campylobacter jejuni, enterotoxigenic Escherichia coli, Salmonella enterica, Giardia duodenalis, Cryptosporidium parvum, Entamoeba histolytica, and norovirus. In Aim 1, we will use molecular and antibody-based measures to study force of infection of the enteric pathogens across a rural-urban gradient. This will represent the first broad-based comparison of seroepidemiologic measures against patent infection for enterics. In Aim 2, we will estimate enteric pathogen force of infection by applying current-status models to population-based, cross-sectional serology surveys in the region, and will benchmark the cross-sectional estimates against those obtained in the concurrent longitudinal study. In Aim 3, we will study IgG and IgA kinetics following infection for each of the 7 pathogens, and develop models to accurately predict recent infections and incidence from antibody levels measured in cross-sectional serology surveys. Completion of these aims will result in generalizable seroepidemiologic methods that have the potential to transform measurement of enteric pathogen transmission and burden in low-resource settings.