Ralph M Parsons Laboratory, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
Ralph M Parsons Laboratory, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
Lancet Planet Health. 2018 Sep;2(9):e406-e413. doi: 10.1016/S2542-5196(18)30175-X.
Many large dams are constructed annually in Africa, with associated reservoirs that might exacerbate the risk of malaria in new villages built nearby. We aimed to investigate the heterogeneous risk of malaria around reservoirs related to the impact of wind direction on malaria transmission.
Between June 15, 2012, and April 22, 2015, we obtained field data on climate and hydrological conditions, and monitored Anopheles mosquito populations around the Koka reservoir in Ethiopia using in-situ weather stations, mosquito light traps, and larval dipping. The field data were used to calibrate a field-tested, spatially explicit mechanistic malaria transmission model, the Hydrology, Entomology, and Malaria Transmission Simulator (HYDREMATS), to investigate the effect of relative wind direction on malaria transmission and associated mechanisms. We combined our simulation results and observational data to assess the association between village location around a reservoir and risk of malaria.
HYDREMATS simulations showed that wind blowing from a village towards a reservoir increases the size of malaria vector populations, whereas wind blowing from a reservoir towards a village decreases the size of malaria vector populations, which was consistent with our field data. Larval mortality is low in locations with village-to-reservoir wind due to weak surface waves, and this wind direction creates conditions that enable mosquitoes to identify village locations more easily than in conditions caused by reservoir-to-village wind, which increases the size of malaria vector populations, and thus malaria transmission. Among the wind conditions investigated (0·5-5 m/s), the effect of CO attraction on the size of the Anopheles population was largest at wind speeds of 0·5 m/s and 1 m/s, decreasing with higher wind speed. At a wind speed of 5 m/s, the effect of CO attraction was negligible, whereas the effect of waves was strongest. The effect of advection on Anopheles population size was negligible at all wind speeds and wind directions.
The effect of wind on malaria transmission around reservoirs can be substantial. The transmission of malaria can be minimised if the location of villages situated near a reservoir is carefully considered. For areas in which the environmental conditions surrounding a resevoir are equal, villages should be located downwind of reservoirs to reduce the incidence of malaria, although further research will be required in locations where wind direction changes in different seasons.
US National Science Foundation, and Cooperative Agreement between the Masdar Institute of Science and Technology, Abu Dhabi, UAE, and the Massachusetts Institute of Technology, Cambridge, MA, USA.
非洲每年都有许多大型水坝建成，与之相关的水库可能会使附近新建村庄的疟疾风险恶化。我们旨在研究与风向对疟疾传播的影响有关的水库周围疟疾的异质风险。
在 2012 年 6 月 15 日至 2015 年 4 月 22 日期间，我们获得了气候和水文条件的实地数据，并使用现场气象站、蚊虫诱捕器和幼虫浸渍法监测了埃塞俄比亚科卡水库周围的疟蚊种群。实地数据用于校准经过现场测试的空间明确的疟疾传播模型，即水文学、昆虫学和疟疾传播模拟器（HYDREMATS），以研究相对风向对疟疾传播和相关机制的影响。我们将我们的模拟结果和观测数据结合起来，评估了村庄在水库周围的位置与疟疾风险之间的关联。
HYDREMATS 模拟结果表明，从村庄吹向水库的风会增加疟疾媒介种群的大小，而从水库吹向村庄的风会减少疟疾媒介种群的大小，这与我们的实地数据一致。由于表面波较弱，在有村庄到水库的风的地方，幼虫死亡率较低，而这种风向使得蚊子更容易识别村庄的位置，而不是水库到村庄的风，这会增加疟疾媒介种群的大小，从而增加疟疾传播。在所研究的风况（0.5-5 m/s）中，CO 吸引力对疟蚊种群大小的影响在风速为 0.5 m/s 和 1 m/s 时最大，随着风速的增加而减小。在 5 m/s 的风速下，CO 吸引力的影响可以忽略不计，而波的影响最强。在所有风速和风向下，平流对疟蚊种群大小的影响可以忽略不计。
风对水库周围疟疾传播的影响可能很大。如果仔细考虑位于水库附近的村庄的位置，可以最大程度地减少疟疾的传播。对于水库周围环境条件相等的地区，村庄应位于水库的下风处，以降低疟疾的发病率，尽管还需要在不同季节风向变化的地区进行进一步的研究。
美国国家科学基金会，以及 Masdar 科学与技术学院与马萨诸塞州技术研究所之间的合作协议，阿布扎比，阿联酋和马萨诸塞州技术研究所，剑桥，MA，美国。
