Artemisinin Resistance in Africa: its emergence and evolution in Rwanda

摘要 青蒿素联合疗法(ACTs)是对抗疟疾的主要抗疟疾疗法。 恶性疟原虫在世界各地流行。虽然抗药性在亚洲很普遍，但还没有。 在全球发病率和死亡率最高的非洲观察到。青蒿素与ACT 非洲的抗药性将是一个严重的挫折，因为没有下一代抗疟疾药物准备好 部署。卢旺达最近关于青蒿素抗药性有效的报告令人严重关切。最近 卢旺达的治疗效果研究发现，寄生虫清除延迟的患者比例很高， 该基因与K13基因中青蒿素抗性突变R561H有关。因此，它 非洲似乎正在接近完全形成的抵抗，就像东南亚所看到的那样。新证据显示 这种突变出现在非洲内部，没有从亚洲传播，因此代表了生物学上的独一无二 去非洲。鉴于坦率的青蒿素耐药性在全国蔓延的潜在破坏性后果 这一建议旨在提高我们对突变及其生物学、起源、 过去和正在进行的扩散以及影响扩散的因素。了解这些动态对于 预测ACTs的长期有效性，并评估和制定有效的控制措施。在……里面 这项提议的第一个目标是了解传播的程度，以及它随着时间的变化有多快。我们 将利用卢旺达国内和周边国家的广泛协作网络 随着时间的推移，在卢旺达和其他国家的邻近地区进行大规模抽样和基因组学研究 绘制并研究耐药性的传播。这将使用高通量的靶向测序来完成 这使得我们可以对成千上万的样本进行基因分型。使用生成的丰富的基因分型和空间数据， 我们还将询问有关寄生虫迁移和可能影响传播的因素的问题。我们的第二个 目标是寻找可能进一步支持青蒿素或伙伴药物耐药性的其他突变。基于 我们从东南亚了解到，经常有补偿性突变增加适合度 青蒿素耐药突变株K13。为了检测补偿性突变，我们将在全基因组范围内进行 关联研究和纵向分析。我们的第三个目标是研究突变体和野生的相对适合度。 用新的统计学方法检查体内突变和野生型寄生虫 多克隆感染；和体外竞争分析，以及蚊子饲料，以检查差异 在人体血液阶段和传播过程中都是健康的。我们的最终目标是使用来自 以上旨在建立一个模型，并预测未来耐药性的扩散。总之，这项研究将提供一种 全面了解卢旺达不断演变的耐药性，并为公共卫生提供可操作的信息。

ABSTRACT Artemisinin combination therapies (ACTs) are the mainstay antimalarial treatment combating Plasmodium falciparum malaria around the world. While resistance is widespread in Asia, it has not yet been observed in Africa where the majority of the global morbidity and mortality occurs. Artemisinin and ACT resistance in Africa would be a serious setback as there are no next-generation antimalarials ready for deployment. Recent reports in Rwanda of validated artemisinin resistance are of grave concern. A recent therapeutic efficacy study in Rwanda found a high prevalence of patients with delayed parasite clearance, which was associated with a validated artemisinin resistance mutation R561H in the K13 gene. Thus, it appears Africa is moving closer to fully formed resistance, as seen in Southeast Asia. New evidence shows that this mutation has arisen within Africa and was not spread from Asia, and thus, represents biology unique to Africa. Given the potential devastating consequences of frank artemisinin resistance spreading across the continent, this proposal is designed to improve our understanding of the mutation and its biology, its origin, its past and ongoing spread and the factors that impact the spread. Understanding these dynamics is critical to predicting the long-term effectiveness of ACTs and to evaluating and formulating effective control efforts. In this proposal the first goal is to understand the extent of spread and how quickly it is changing with time. We will leverage an extensive collaborative network within Rwanda and in surrounding countries to perform large scale sampling and genomics studies across Rwanda and neighboring areas in other countries over time to map and study the spread of resistance. This will be accomplished using high-throughput targeted sequencing allowing us to genotype tens of thousands of samples. Using the generated rich genotyping and spatial data, we will also ask questions about parasite migration and factors that may be impacting the spread. Our second goal is to look for other mutations that may further support resistance to artemisinin or partner drugs. Based on our knowledge from Southeast Asia, there are often compensatory mutations that increase the fitness of artemisinin resistance mutations in K13. To detect compensatory mutations we will perform genome wide association studies and longitudinal analyses. Our third goal is to study the relative fitness of mutant and wild type parasites examining mutant and wildtype parasites in vivo using new statistical methods to examine polyclonal infections; and in vitro competition assays, as well as mosquito feeds, to examine differences in fitness in both the human blood stage and during transmission. Our final goal is to use the information from the above aims to build a model and predict the future spread of resistance. Together, this study will provide a comprehensive view of evolving resistance in Rwanda and provide actionable information for public health.