Mukhta2018-the effect of bednet coverage on malaria transmission in South Sudan

A campaign for malaria control, using Long Lasting Insecticide Nets (LLINs) was launched in South Sudan in 2009. The success of such a campaign often depends upon adequate available resources and reliable surveillance data which help officials understand existing infections. An optimal allocation of resources for malaria control at a sub-national scale is therefore paramount to the success of efforts to reduce malaria prevalence. In this paper, we extend an existing SIR mathematical model to capture the effect of LLINs on malaria transmission. Available data on malaria is utilized to determine realistic parameter values of this model using a Bayesian approach via Markov Chain Monte Carlo (MCMC) methods. Then, we explore the parasite prevalence on a continued rollout of LLINs in three different settings in order to create a sub-national projection of malaria. Further, we calculate the model's basic reproductive number and study its sensitivity to LLINs' coverage and its efficacy. From the numerical simulation results, we notice a basic reproduction number, [Formula: see text], confirming a substantial increase of incidence cases if no form of intervention takes place in the community. This work indicates that an effective use of LLINs may reduce [Formula: see text] and hence malaria transmission. We hope that this study will provide a basis for recommending a scaling-up of the entry point of LLINs' distribution that targets households in areas at risk of malaria.

Model is encoded by Ruby and submitted to BioModels by Ahmad Zyoud

2009年，南苏丹启动了一项利用长效杀虫剂处理蚊帐（Long Lasting Insecticide Nets, LLINs）的疟疾防控行动。此类防控行动的成效往往取决于充足的可用资源与可靠的监测数据——这些信息可帮助官员掌握现有感染情况。因此，在次国家级尺度上优化疟疾防控资源配置，对于降低疟疾流行率的工作成效至关重要。

本研究对现有SIR（易感者-感染者-恢复者）数学模型进行拓展，以刻画长效杀虫剂处理蚊帐对疟疾传播的影响。我们利用现有疟疾相关数据，通过基于马尔可夫链蒙特卡洛（Markov Chain Monte Carlo, MCMC）方法的贝叶斯推断，确定该模型的合理参数取值。随后，本研究针对三种不同场景下持续推广长效杀虫剂处理蚊帐的情形，探究疟原虫流行率的变化规律，以此生成次国家级尺度的疟疾流行预测结果。此外，本研究还计算了该模型的基本再生数（basic reproductive number），并分析其对长效杀虫剂处理蚊帐覆盖范围与防控效力的敏感性。

从数值模拟结果来看，本研究得到的基本再生数[Formula: see text]证实：若社区内不采取任何干预措施，疟疾发病例数将大幅上升。本研究结果表明，合理有效使用长效杀虫剂处理蚊帐，可降低[Formula: see text]，进而抑制疟疾传播。我们期望本研究能够为推广面向疟疾高风险地区家庭的长效杀虫剂处理蚊帐配送工作提供决策依据，以进一步扩大该类防控物资的覆盖规模。

本模型由Ruby语言编码，并由Ahmad Zyoud提交至BioModels数据库。