Zhu Lin, Müller Günter C, Marshall John M, Arheart Kristopher L, Qualls Whitney A, Hlaing WayWay M, Schlein Yosef, Traore Sekou F, Doumbia Seydou, Beier John C
Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, FL, USA.
Department of Microbiology and Molecular Genetics, IMRIC, Kuvin Centre for the Study of Infectious and Tropical Diseases, Faculty of Medicine, Hebrew University, Jerusalem, Israel.
Malar J. 2017 Jul 3;16(1):266. doi: 10.1186/s12936-017-1920-y.
Residual malaria transmission has been reported in many areas even with adequate indoor vector control coverage, such as long-lasting insecticidal nets (LLINs). The increased insecticide resistance in Anopheles mosquitoes has resulted in reduced efficacy of the widely used indoor tools and has been linked with an increase in outdoor malaria transmission. There are considerations of incorporating outdoor interventions into integrated vector management (IVM) to achieve malaria elimination; however, more information on the combination of tools for effective control is needed to determine their utilization.
A spatial individual-based model was modified to simulate the environment and malaria transmission activities in a hypothetical, isolated African village setting. LLINs and outdoor attractive toxic sugar bait (ATSB) stations were used as examples of indoor and outdoor interventions, respectively. Different interventions and lengths of efficacy periods were tested. Simulations continued for 420 days, and each simulation scenario was repeated 50 times. Mosquito populations, entomologic inoculation rates (EIRs), probabilities of local mosquito extinction, and proportion of time when the annual EIR was reduced below one were compared between different intervention types and efficacy periods.
In the village setting with clustered houses, the combinational intervention of 50% LLINs plus outdoor ATSBs significantly reduced mosquito population and EIR in short term, increased the probability of local mosquito extinction, and increased the time when annual EIR is less than one per person compared to 50% LLINs alone; outdoor ATSBs alone significantly reduced mosquito population in short term, increased the probability of mosquito extinction, and increased the time when annual EIR is less than one compared to 50% LLINs alone, but there was no significant difference in EIR in short term between 50% LLINs and outdoor ATSBs. In the village setting with dispersed houses, the combinational intervention of 50% LLINs plus outdoor ATSBs significantly reduced mosquito population in short term, increased the probability of mosquito extinction, and increased the time when annual EIR is less than one per person compared to 50% LLINs alone; outdoor ATSBs alone significantly reduced mosquito population in short term, but there were no significant difference in the probability of mosquito extinction and the time when annual EIR is less than one between 50% LLIN and outdoor ATSBs; and there was no significant difference in EIR between all three interventions. A minimum of 2 months of efficacy period is needed to bring out the best possible effect of the vector control tools, and to achieve long-term mosquito reduction, a minimum of 3 months of efficacy period is needed.
The results highlight the value of incorporating outdoor vector control into IVM as a supplement to traditional indoor practices for malaria elimination in Africa, especially in village settings of clustered houses where LLINs alone is far from sufficient.
即使在室内病媒控制覆盖率足够的许多地区，如长效驱虫蚊帐（LLINs），仍有残余疟疾传播的报道。按蚊对杀虫剂的抗性增加，导致广泛使用的室内防治工具效果降低，并与室外疟疾传播增加有关。考虑将室外干预措施纳入综合病媒管理（IVM）以实现疟疾消除；然而，需要更多关于有效控制工具组合的信息来确定其应用。
修改了一个基于个体的空间模型，以模拟一个假设的、孤立的非洲村庄环境中的环境和疟疾传播活动。分别以LLINs和室外诱蚊取食毒饵（ATSB）站作为室内和室外干预措施的示例。测试了不同的干预措施和有效期长度。模拟持续420天，每个模拟场景重复50次。比较了不同干预类型和有效期之间的蚊虫种群、昆虫学接种率（EIRs）、当地蚊虫灭绝概率以及年EIR降低至每人低于1的时间比例。
在房屋聚集的村庄环境中，与单独使用50%的LLINs相比，50%的LLINs加上室外ATSBs的联合干预在短期内显著减少了蚊虫种群和EIR，增加了当地蚊虫灭绝的概率，并增加了年EIR低于每人1的时间；单独使用室外ATSBs在短期内显著减少了蚊虫种群，增加了蚊虫灭绝的概率，并增加了年EIR低于每人1的时间，但50%的LLINs与室外ATSBs在短期内的EIR没有显著差异。在房屋分散的村庄环境中，与单独使用50%的LLINs相比，50%的LLINs加上室外ATSBs的联合干预在短期内显著减少了蚊虫种群，增加了蚊虫灭绝的概率，并增加了年EIR低于每人1的时间；单独使用室外ATSBs在短期内显著减少了蚊虫种群，但50%的LLINs与室外ATSBs在蚊虫灭绝概率和年EIR低于每人1的时间方面没有显著差异；并且所有三种干预措施的EIR没有显著差异。病媒控制工具需要至少2个月的有效期才能发挥最佳效果，要实现长期减少蚊虫，需要至少3个月的有效期。
结果突出了将室外病媒控制纳入IVM作为非洲疟疾消除传统室内措施补充的价值，特别是在房屋聚集的村庄环境中，仅靠LLINs远远不够。
