Eckhoff Philip A, Wenger Edward A, Godfray H Charles J, Burt Austin
Institute for Disease Modeling, Bellevue, WA 98005;
Institute for Disease Modeling, Bellevue, WA 98005.
Proc Natl Acad Sci U S A. 2017 Jan 10;114(2):E255-E264. doi: 10.1073/pnas.1611064114. Epub 2016 Dec 27.
The renewed effort to eliminate malaria and permanently remove its tremendous burden highlights questions of what combination of tools would be sufficient in various settings and what new tools need to be developed. Gene drive mosquitoes constitute a promising set of tools, with multiple different possible approaches including population replacement with introduced genes limiting malaria transmission, driving-Y chromosomes to collapse a mosquito population, and gene drive disrupting a fertility gene and thereby achieving population suppression or collapse. Each of these approaches has had recent success and advances under laboratory conditions, raising the urgency for understanding how each could be deployed in the real world and the potential impacts of each. New analyses are needed as existing models of gene drive primarily focus on nonseasonal or nonspatial dynamics. We use a mechanistic, spatially explicit, stochastic, individual-based mathematical model to simulate each gene drive approach in a variety of sub-Saharan African settings. Each approach exhibits a broad region of gene construct parameter space with successful elimination of malaria transmission due to the targeted vector species. The introduction of realistic seasonality in vector population dynamics facilitates gene drive success compared with nonseasonal analyses. Spatial simulations illustrate constraints on release timing, frequency, and spatial density in the most challenging settings for construct success. Within its parameter space for success, each gene drive approach provides a tool for malaria elimination unlike anything presently available. Provided potential barriers to success are surmounted, each achieves high efficacy at reducing transmission potential and lower delivery requirements in logistically challenged settings.
为消除疟疾并永久消除其巨大负担而做出的新努力,凸显了在不同环境中何种工具组合足够以及需要开发哪些新工具的问题。基因驱动蚊子构成了一组有前景的工具,有多种不同的可能方法,包括用引入的限制疟疾传播的基因进行种群替代、驱动Y染色体使蚊子种群崩溃,以及基因驱动破坏生育基因从而实现种群抑制或崩溃。这些方法中的每一种最近在实验室条件下都取得了成功和进展,这增加了理解每种方法如何在现实世界中应用以及每种方法潜在影响的紧迫性。由于现有的基因驱动模型主要关注非季节性或非空间动态,因此需要新的分析。我们使用一个基于个体的、空间明确的、随机的、机械的数学模型,在撒哈拉以南非洲的各种环境中模拟每种基因驱动方法。由于目标病媒物种的原因,每种方法在基因构建参数空间中都有一个广泛的区域,能够成功消除疟疾传播。与非季节性分析相比,在病媒种群动态中引入现实的季节性有助于基因驱动取得成功。空间模拟说明了在构建成功最具挑战性的环境中,对释放时间、频率和空间密度的限制。在其成功的参数空间内,每种基因驱动方法都提供了一种与目前任何可用工具不同的消除疟疾的工具。如果能够克服成功的潜在障碍,每种方法在降低传播潜力方面都能达到高效,并且在后勤挑战较大的环境中所需的投放量更低。