Killeen Gerry F, Smith Thomas A
Ifakara Health Research and Development Centre, Box 53, Ifakara, Kilombero, Morogoro, United Republic of Tanzania.
Trans R Soc Trop Med Hyg. 2007 Sep;101(9):867-80. doi: 10.1016/j.trstmh.2007.04.022. Epub 2007 Jul 13.
Domestic and personal protection measures against malaria exposure either divert host-seeking vectors to other hosts or kill those attempting to feed. Here, we explicitly model mosquito host-seeking processes in the context of local host availability and elucidate the impacts and mechanisms of pyrethroid-treated bed nets in Africa. It has been suggested that excitorepellent insecticides could increase exposure of unprotected humans by concentrating mosquito biting activity on this vulnerable group. This worst-case scenario is confirmed as a possibility where vector populations lack alternative hosts, but an approximate 'break-even' scenario, with users experiencing little overall change in exposure, is more likely because of increased mosquito mortality while foraging for resources. Insecticidal nets are predicted to have epidemiologically significant impacts on transmission experienced by users and non-users at levels of coverage that can be achieved by sustainable net distribution systems, regardless of excitorepellency or the ecological setting. The results are consistent with the outcome of several randomised controlled trials, predicting enormous reductions in transmission at individual and community levels. As financial support, technology and distribution systems for insecticide-treated nets improve, massive reductions in malaria transmission could be realised.
针对疟疾暴露的家庭和个人防护措施，要么将寻找宿主的病媒转移到其他宿主身上，要么杀死那些试图叮咬的病媒。在此，我们在当地宿主可利用性的背景下明确模拟蚊子寻找宿主的过程，并阐明在非洲使用拟除虫菊酯处理过的蚊帐的影响和作用机制。有人提出，驱避性杀虫剂可能会将蚊子的叮咬活动集中在这个弱势群体身上，从而增加未受保护人群的暴露风险。在病媒种群缺乏替代宿主的情况下，这种最坏的情况被证实是有可能的，但由于蚊子在寻找资源时死亡率增加，更有可能出现一种近似“收支平衡”的情况，即使用者总体暴露变化不大。预计在可持续蚊帐分发系统能够实现的覆盖率水平下，杀虫蚊帐将对使用者和非使用者所经历的传播产生具有流行病学意义的影响，无论其是否具有驱避性或生态环境如何。这些结果与几项随机对照试验的结果一致，预测在个体和社区层面传播将大幅减少。随着用于处理蚊帐的财政支持、技术和分发系统的改善，疟疾传播有望大幅减少。
