Courtenay O, Gillingwater K, Gomes P A F, Garcez L M, Davies C R
Ecology and Epidemiology Group, Department of Biological Sciences, University of Warwick, Coventry, UK.
Med Vet Entomol. 2007 Jun;21(2):168-76. doi: 10.1111/j.1365-2915.2007.00678.x.
The entomological efficacy of using 25% deltamethrin EC insecticide-treated bednets (ITNs) was evaluated against the sandfly Lutzomyia longipalpis Lutz and Neiva (Diptera: Psychodidae), the principal vector of zoonotic visceral leishmaniasis (ZVL) in Latin America. A crossover field study in Amazon Brazil (Marajó Island, Pará State) demonstrated that, compared with untreated nets, the insecticide increased the barrier effect of nets by 39% (95% confidence interval [CI] 34-44%), reduced human landing rates by 80% (95% CI 62-90%) and increased the 24-h mortality rate from 0% to 98% (95% CI 93-99%) inside ITNs. The presence of an ITN also reduced the human landing rate on unprotected persons outside the net in the same room by 56% (95% CI 52-59%), and increased 24-h mortality to 68% (95% CI 62-73%) compared to 0.4% (0.1-2.0%) in untreated houses. The reduction in human landing rates in ITN rooms was associated with a doubling in the proportion of sandflies alighting on walls compared with that in untreated rooms, which was attributed to insecticide-induced excito-repellency. There was no evidence that sandflies were diverted onto unprotected hosts. Human landing catches inside houses peaked between 19.00 hours and 23.00 hours and declined steadily to zero at 02.00 hours and thereafter. House-to-house questionnaires established that only 34% of households owned at least one net (median two, range 1-8), only 20% of the population slept under a net (33% of 0-5-year-old children), and the majority (73%) of the population slept in hammocks. Combined data pertaining to sleeping times for children and sandfly activity period indicate that > 50% of sandfly bites inside houses, and substantially more outside houses, were taken before a third of children were potentially protected by a net. This study demonstrates the clear entomological efficacy of ITNs against Lu. longipalpis in this endemic region. The effectiveness of ITNs at preventing ZVL infection and disease has still to be evaluated.
评估了使用25%溴氰菊酯乳油杀虫剂处理过的蚊帐（ITNs）对沙蝇长须罗蛉（Lutzomyia longipalpis Lutz and Neiva）（双翅目：毛蠓科）的昆虫学效果，长须罗蛉是拉丁美洲人畜共患内脏利什曼病（ZVL）的主要传播媒介。在巴西亚马逊地区（帕拉州马拉若岛）进行的一项交叉现场研究表明，与未处理的蚊帐相比，杀虫剂使蚊帐的屏障效果提高了39%（95%置信区间[CI] 34 - 44%），使人类叮咬率降低了80%（95% CI 62 - 90%），并使ITNs内24小时死亡率从0%提高到98%（95% CI 93 - 99%）。ITN的存在还使同一房间内未受保护的人身上的人类叮咬率降低了56%（95% CI 52 - 59%），与未处理房屋中0.4%（0.1 - 2.0%）相比，24小时死亡率提高到68%（95% CI 62 - 73%）。与未处理房间相比，ITN房间内人类叮咬率的降低与落在墙上的沙蝇比例翻倍有关，这归因于杀虫剂引起的兴奋驱避作用。没有证据表明沙蝇会转向未受保护的宿主。房屋内的人类叮咬捕获量在19:00至23:00之间达到峰值，并在02:00及之后稳步降至零。逐户问卷调查显示，只有34%的家庭拥有至少一顶蚊帐（中位数为两顶，范围为1 - 8顶），只有20%的人口睡在蚊帐下（0至5岁儿童中有33%），大多数（73%）人口睡在吊床上。有关儿童睡眠时间和沙蝇活动期的综合数据表明，房屋内超过50%的沙蝇叮咬，以及房屋外更多的叮咬，是在三分之一的儿童可能受到蚊帐保护之前发生的。这项研究证明了ITNs在该流行地区对长须罗蛉具有明显的昆虫学效果。ITNs在预防ZVL感染和疾病方面的有效性仍有待评估。
