Artemisinin Resistance in Africa: its emergence and evolution in Rwanda

摘要 青蒿素综合疗法是防治疟疾的主要抗疟疗法， 世界各地的恶性疟原虫疟疾。虽然耐药现象在亚洲普遍存在，但迄今为止， 非洲是全球发病率和死亡率最高的地区。青蒿素和ACT 非洲的耐药性将是一个严重的挫折，因为没有下一代抗疟药物可用于 部署.最近在卢旺达关于经证实的青蒿素抗药性的报告令人严重关切。最近的一 在卢旺达进行的一项疗效研究发现，寄生虫清除延迟的患者发病率很高， 这与K13基因中经验证的青蒿素抗性突变R561 H相关。因此 似乎非洲正朝着完全形成抵抗的方向发展，就像在东南亚看到的那样。新的证据表明 这种突变是在非洲发生的，而不是从亚洲传播的，因此， 去非洲鉴于青蒿素抗药性在整个非洲蔓延的潜在破坏性后果， 大陆，这项建议旨在提高我们对突变及其生物学，其起源， 过去和正在进行的传播以及影响传播的因素。了解这些动态对于 预测青蒿素综合疗法的长期有效性，评价和制定有效的控制措施。在 这项建议的第一个目标是了解传播的程度以及它随时间的变化有多快。我们 将利用卢旺达和周边国家广泛的合作网络， 随着时间的推移，在卢旺达和其他国家的邻近地区进行规模取样和基因组学研究， 绘制并研究耐药性的传播。这将使用高通量靶向测序来完成 让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 我们的目标是寻找可能进一步支持对青蒿素或伙伴药物耐药性的其他突变。基于 根据我们对东南亚的了解，通常会有补偿性突变， K13的青蒿素耐药突变。为了检测补偿突变，我们将进行全基因组检测， 关联分析和纵向分析。我们的第三个目标是研究突变体和野生体的相对适合度 型寄生虫检查突变体和野生型寄生虫在体内使用新的统计方法来检查 多克隆感染;以及体外竞争试验，以及蚊子饲料，以检查 在人类血液阶段和传播过程中的适应性。我们的最终目标是利用 上述研究旨在建立一个模型并预测耐药性的未来蔓延。这项研究将提供一个 全面了解卢旺达不断演变的耐药性，并为公共卫生提供可采取行动的信息。

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.