如果病媒控制工作完全集中在室内发生的传播,而不解决在室外和睡眠时间以外叮咬的病媒,则消除疟疾的可能性不大。诸如空间驱虫剂的附加控制工具可以提供填充该间隙所需的个人保护。然而,由于驱避剂不会杀死蚊子,因此尚不清楚媒介是否会从使用空间驱避剂的家庭转移到不使用空间驱避剂的家庭。
在基隆贝罗进行了24周的交叉研究,坦桑尼亚。在以下三种覆盖情况下,在使用或不使用0.03%的室外燃烧的透氟菊酯线圈的90个家庭中,测量了每个家庭的静息和充血蚊子的密度以及人类血液指数(HBI):(i)无覆盖(空白线圈);(ii)驱避剂线圈的完全覆盖;(iii)驱避剂和空白线圈的不完全覆盖。使用蚊子吸引器,每周三天从所有参与家庭的内部和外部收集蚊子,共24周。在三个随机家庭中连续六个晚上进行了室内和室外人体着陆收集,以确认线圈的驱除效果和局部矢量叮咬时间。
主要载体是阿拉伯按蚊和按蚊(sensustricto),在户外喂养,在睡眠时间以外,对人类和动物。尽管家庭密度没有降低,但空间驱避剂使阿拉伯按蚊的上岸减少了80%。HBI为An。与无覆盖情况下的房屋相比,在不完全覆盖情况下没有驱虫剂的家庭中,阿拉伯明显更高(赔率1.71;95%CI:1.04-2.83;P=0.03)。这表明An。寻求人类血餐的阿拉伯蚊子被从驱虫剂使用者转移到非使用者。排斥线圈不影响An。funestus密度或HBI。
在Kilombero山谷的睡眠时间以外,大量的疟疾病媒活动正在发生。排斥线圈对局部An提供了一些保护。阿拉伯,但不能抵抗局部(和潜在的拟除虫菊酯抗性)An。funestus.基于拟除虫菊酯的空间驱避剂可以提供一定程度的个人保护,然而,整体的公共健康益处是值得怀疑的,并且可能是不公平的,因为它们的使用可能会将疟疾病媒转移到那些不使用它们的人身上。
Malaria elimination is unlikely to occur if vector control efforts focus entirely on transmission occurring indoors without addressing vectors that bite outdoors and outside sleeping hours. Additional control tools such as spatial repellents may provide the personal protection required to fill this gap. However, since repellents do not kill mosquitoes it is unclear if vectors will be diverted from households that use spatial repellents to those that do not.
A crossover
study was performed over 24 weeks in Kilombero, Tanzania. The density of resting and blood-engorged mosquitoes and human blood index (HBI) of malaria vector species per household was measured among 90 households using or not using 0.03 % transfluthrin coils burned outdoors under three coverage scenarios: (i) no coverage (blank coils); (ii) complete coverage of repellent coils; and (iii) incomplete coverage of repellent and blank coils. Mosquitoes were collected three days a week for 24 weeks from the inside and outside of all participating households using mosquito aspirators. Paired indoor and outdoor human landing collections were performed in three random households for six consecutive nights to confirm repellent efficacy of the coils and local vector biting times.
The main vectors were Anopheles arabiensis and Anopheles funestus (sensu stricto), which fed outdoors, outside sleeping hours, on humans as well as animals. Anopheles arabiensis landings were reduced by 80 % by the spatial repellent although household densities were not reduced. The HBI for An. arabiensis was significantly higher among households without repellents in the incomplete coverage scenario compared to houses in the no coverage scenario (Odds ratio 1.71; 95 % CI: 1.04-2.83; P = 0.03). This indicated that An. arabiensis mosquitoes seeking a human blood meal were diverted from repellent users to non-users. The repellent coils did not affect An. funestus densities or HBI.
Substantial malaria vector activity is occurring outside sleeping hours in the Kilombero valley. Repellent coils provided some protection against local An. arabiensis but did not protect against local (and potentially pyrethroid-resistant) An. funestus. Pyrethroid-based spatial repellents may offer a degree of personal protection, however the overall public health benefit is doubtful and potentially iniquitous as their use may divert malaria vectors to those who do not use them.