Reducing Plasmodium falciparum Malaria Transmission in Africa: A Model-Based Evaluation of Intervention Strategies
Reducing Plasmodium falciparum Malaria Transmission in Africa: A Model-Based Evaluation of Intervention Strategies
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DOI：
10.1371/journal.pmed.1000324
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发表时间：
2010-08-01
期刊：
影响因子：
15.8
通讯作者：
Ghani, Azra C.
中科院分区：
文献类型：
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作者：
Griffin, Jamie T.;Hollingsworth, T. Deirdre;Ghani, Azra C.
背景：在过去十年中，整个非洲扩大了疟疾干预覆盖面。然而，目前尚不清楚使用现有的工具可以实现多大程度的总体减少传播。方法和发现：我们开发了一个基于个体的恶性疟原虫在非洲传播的模拟模型，其中包括三个主要的媒介物种(冈比亚按蚊、冈比亚按蚊和冈比亚按蚊)。Arabiens和An.Funestus)与来自非洲34个传播环境的寄生虫流行数据进行拟合而获得的参数。我们纳入了改用青蒿素联合疗法(ACT)的影响，并从2000年起增加了长效驱虫蚊帐(LLIN)的覆盖率。然后，我们探讨了在六个具有代表性的环境中继续推出LLIN、额外的几轮室内滞留喷洒(IRS)、大规模筛查和治疗以及未来的RTS、S/AS01疫苗在不同传播强度(根据年度昆虫学接种率总结：1个设置为低、3个设置为中等、2个设置为高EIR)、媒介-物种组合和季节性模式下对传播的影响。在所有情况下，我们都认为80%的干预覆盖率是一个现实的目标。在低传播率(EIR，每人每年3ibppy[感染叮咬])环境中，只要使用水平高且持续，LLIN就有可能将疟疾传播降低到低水平(所有年龄组的寄生虫流行率为1%)。在两个中等传播设置(EIR、43和81ibppy)中，使用滴滴涕和MSAT进行额外的IRS治疗可能会将寄生虫流行率降至1%的阈值以下。然而，在第三个(EIR=46)中，具有一个。在阿拉伯流行的情况下，这些干预措施不足以达到这一门槛。在这两个高传播环境(EIR，586和675 ibppy)，要么需要不切实际的高覆盖率水平(90%)，要么需要新的工具和/或实质性的社会改善，尽管现有工具和现实的覆盖率水平可以显著降低患病率。结论：使用现有工具的干预措施可以大大减少非洲恶性疟原虫的传播和相关疾病负担。如果通过推出干预措施实现全面和持续的干预计划，在媒介主要是内嗜性(室内休息)的低至中等传播环境中，寄生虫流行阈值有可能降低到1%。在高传播环境和媒介主要为外嗜性(室外栖息)的环境中，将需要针对外嗜性(户外叮咬)、外嗜性和部分食动物性蚊子的额外新工具。
Background: Over the past decade malaria intervention coverage has been scaled up across Africa. However, it remains unclear what overall reduction in transmission is achievable using currently available tools.Methods and Findings: We developed an individual-based simulation model for Plasmodium falciparum transmission in an African context incorporating the three major vector species (Anopheles gambiae s.s., An. arabiensis, and An. funestus) with parameters obtained by fitting to parasite prevalence data from 34 transmission settings across Africa. We incorporated the effect of the switch to artemisinin-combination therapy (ACT) and increasing coverage of long-lasting insecticide treated nets (LLINs) from the year 2000 onwards. We then explored the impact on transmission of continued roll-out of LLINs, additional rounds of indoor residual spraying (IRS), mass screening and treatment (MSAT), and a future RTS,S/AS01 vaccine in six representative settings with varying transmission intensity (as summarized by the annual entomological inoculation rate, EIR: 1 setting with low, 3 with moderate, and 2 with high EIRs), vector-species combinations, and patterns of seasonality. In all settings we considered a realistic target of 80% coverage of interventions. In the low-transmission setting (EIR, 3 ibppy [infectious bites per person per year]), LLINs have the potential to reduce malaria transmission to low levels (< 1% parasite prevalence in all age-groups) provided usage levels are high and sustained. In two of the moderate-transmission settings (EIR, 43 and 81 ibppy), additional rounds of IRS with DDT coupled with MSAT could drive parasite prevalence below a 1% threshold. However, in the third (EIR = 46) with An. arabiensis prevailing, these interventions are insufficient to reach this threshold. In both high-transmission settings (EIR, 586 and 675 ibppy), either unrealistically high coverage levels (> 90%) or novel tools and/or substantial social improvements will be required, although considerable reductions in prevalence can be achieved with existing tools and realistic coverage levels.Conclusions: Interventions using current tools can result in major reductions in P. falciparum malaria transmission and the associated disease burden in Africa. Reduction to the 1% parasite prevalence threshold is possible in low-to moderate-transmission settings when vectors are primarily endophilic (indoor-resting), provided a comprehensive and sustained intervention program is achieved through roll-out of interventions. In high-transmission settings and those in which vectors are mainly exophilic (outdoor-resting), additional new tools that target exophagic (outdoor-biting), exophilic, and partly zoophagic mosquitoes will be required.