After the flood: Optimal strategies to prevent malaria epidemics caused by severe flooding

项目总结/摘要 气候变化的影响，包括洪水等极端天气发生频率的增加， 疟疾和其他病媒传染疾病发病率的变化是一个具有重大公共卫生意义的问题。 因此，迫切需要制定有效的缓解和控制战略。2020年5月，我们试点 在乌干达西部农村进行洪水后疟疾化学预防干预。与两个相邻的 在没有采取干预措施的村庄，我们估计减少了53%（aRR 0.47，95%CI 0.34 - 0.62， p<0.01）。在这些结果的基础上， 该提案旨在评估有针对性的、有时限的疟疾化学预防干预措施的有效性 有和没有幼虫源管理（LSM），以减少过度的疾病负担，在一个常年，高- 在严重洪水之后的传输设置。我们的前提是干预会减少寄生虫 在关键的“反弹”时期，病媒正在重新建立生境， 在条件恢复到洪水前的基线之前，传播水平相对较低。具体而言，我们将： 目的1：确定有或没有围家杀幼虫剂的化学预防效果 应用于减少严重洪水后恶性疟原虫疟疾的发病率。我们将进行一组 在乌干达西部农村的50个村庄（144个集群）进行的随机试验，那里的洪水相对可预测， 比较：（i）LLIN分发（对照），（ii）LLIN分发加上向儿童提供的每月三轮DP ≤12岁（DP），和（iii）LLIN+DP，在幼虫中每两周施用一次杀幼虫剂，为期3个月， 国内空间（DP+Bti）。假设：化学预防将实现持续（≥6个月）降低 与对照组相比，疟疾发病率≥30%，未出现青蒿素耐药性。 目的2：阐明媒介种群的演变，摄食行为，和子孢子率， 洪水后一年内受灾的村庄。我们将每周对成人和青少年进行监测， 哨点住户及家居周围空间内的按蚊。收集的蚊子将 计数并鉴定为种并检测恶性疟原虫子孢子的存在。假设：洪水 将形成无数的小池，为安所青睐。冈比亚复合体，导致优势的AN。冈比亚按蚊 S.S.有可能出现一个。在广泛使用长效驱虫蚊帐的情况下，阿拉伯按蚊是重要的传病媒介。 目标3：评价化学预防的相对成本效益（目标3A），并评估社会 对家庭的经济影响（目标3B）。我们将进行基线和纵向定量 抽样调查，以评估干预措施对㈠经济活动和收入的影响，㈡ 健康寻求和支出，以及（iii）心理健康和福祉。这些数据将告知成本 与对照相比的化学预防的有效性分析（即，避免的每宗个案的相对成本）。 假设：化学预防将减轻洪水后疟疾的负面影响。

PROJECT SUMMARY/ABSTRACT The impact of climate change, including the increased frequency of weather extremes such as flooding, on the incidence of malaria and other vector-borne diseases is an issue of substantial public health importance. Therefore, there is an urgent need to develop effective mitigation and control strategies. In May 2020, we piloted a post-flood malaria chemoprevention intervention in rural western Uganda. When compared to two neighboring villages where no intervention was deployed, we estimated a 53% reduction (aRR 0.47, 95% CI 0.34 – 0.62, p<.01) in malaria incidence in the six months post-intervention. Building on these results, the scientific aim of this proposal is to evaluate the effectiveness of a targeted, time-limited malaria chemoprevention intervention with and without larval source management (LSM) to reduce excess disease burden in a perennial, high- transmission setting following severe flooding. Our premise is that the intervention will reduce the parasite reservoir during the critical “rebound” period, when vectors are re-establishing habitats thereby maintaining relatively low levels of transmission until conditions have returned to the pre-flood baseline. Specifically, we will: Aim 1: Determine the effectiveness of chemoprevention with or without peri-domestic larvicide application to reduce the incidence of P. falciparum malaria after severe flooding. We will conduct a cluster randomized trial in 50 villages (144 clusters) in rural western Uganda, where flooding relatively predictable, to compare: (i) LLIN distribution (control), (ii) LLIN distribution plus three, monthly rounds of DP provided to children ≤12 years of age (DP), and (iii) LLIN+DP with three months of bi-weekly application of larvicide in the peri- domestic space (DP+Bti). Hypothesis: Chemoprevention will achieve a sustained (≥6 months) reduction in malaria incidence of ≥30% compared to the control arm without the emergence of artemisinin resistance. Aim 2: Elucidate the evolution of vector populations, feeding behaviors, and sporozoite rate in affected villages up to one year after flooding. We will perform weekly surveillance for adult and juvenile Anopheles mosquitoes in sentinel households and within the peri-domestic space. Collected mosquitoes will be counted, and identified to species and tested for the presence of P. falciparum sporozoites. Hypothesis: Flooding will create innumerable small pools favored by An. gambiae complex resulting in predominance of An. gambiae s.s. with potential for emergence of An. arabiensis as important vector in setting of widespread LLIN use.23 Aim 3: Evaluate the relative cost-effectiveness of chemoprevention (Aim 3A) and assess social and economic impacts on households (Aim 3B). We will conduct baseline and longitudinal quantitative surveys in sample clusters to evaluate impacts of the interventions on (i) economic activities and income, (ii) health seeking and expenditures, and (iii) mental health and well-being. These data will inform a cost effectiveness analysis of chemoprevention compared to the control (i.e., relative cost per case averted). Hypothesis: Chemoprevention will mitigate negative effects of malaria in the aftermath of a flood.