背景:广泛的媒介控制对于减少全球疟疾的发病率和流行率至关重要,尽管现在进展停滞不前。长效杀虫剂处理过的蚊帐(LLINs)历来是,并留下来,防治疟疾运动中最常用的媒介控制工具之一。LLINs只有在正确使用时才有效,坚持,保留和社区采用,历史上依赖于成功控制次生害虫,包括臭虫。有人认为,在疟疾流行社区中出现了耐拟除虫菊酯的臭虫,并且未能控制感染,这干扰了LLINs的有效使用。因此,应该更好地理解臭虫与常用蚊帐的行为相互作用。
方法:为了研究臭虫(CimexlectulariusL.)和LLINs之间的相互作用,在两种行为测定中,对杀虫剂敏感和对拟除虫菊酯抗性的臭虫被挑战通过两种常用的LLINs,即宿主(血粉)-寻求和聚集-寻求测定。血液喂养和聚集的臭虫的比例,在不同的臭虫生命阶段对聚集时间和死亡率进行了量化和分析。
结果:总体而言,对杀虫剂敏感的臭虫和高抗性臭虫都显示出根据处理状态和网设计不同的通过LIN的能力。溴氰菊酯处理的蚊帐显着阻碍了易感臭虫的摄食和聚集。虽然测试的LLINs都没有显著阻碍对拟除虫菊酯抗性臭虫的摄食(未摄食臭虫通过网),未经处理的蚊帐,有小的网孔,阻止喂食的臭虫通过。死亡率只见于易感臭虫,溴氰菊酯处理的蚊帐(63.5±10.7%)的死亡率明显高于氯菊酯处理的蚊帐(2.0±0.9%)。
结论:在寻求宿主和聚集的生物测定中,常用的新型LIN未能防止易感和耐拟除虫菊酯的臭虫通过。在两种测定期间在易感臭虫中观察到的总体低且可变的死亡率突出了LLINs对拟除虫菊酯抗性的进化施加强选择压力的潜力。已经,未能控制臭虫的侵扰被认为是导致LLINs放弃或滥用的一个因素。据我们所知,这是第一次,我们已经证明了LLINs在选择具有抗性的次级害虫种群方面的潜力,因此应进一步研究其在拖延疟疾控制计划中的潜在作用。在疟疾流行社区中出现耐拟除虫菊酯的臭虫可能会干扰拟除虫菊酯浸渍的蚊帐的有效使用。我们使用两种行为测定法评估了两种臭虫菌株与常用蚊帐的相互作用,即未喂食的臭虫寻求宿主(血粉)和新喂食的臭虫寻求聚集。这些测定评估了臭虫通过各种蚊帐对宿主线索和聚集刺激的反应。分别。条件纸是文件夹纸的一部分,已暴露于臭虫,并已浸渍有粪便和聚集信息素;它对寻求聚集的喂食臭虫很有吸引力。无条件的斜坡是文件夹纸的类似部分,允许臭虫穿过蚊帐并获得血粉来源。
BACKGROUND: Widespread vector control has been essential in reducing the global incidence and prevalence of malaria, despite now stalled progress. Long-lasting insecticide-treated nets (LLINs) have historically been, and remain, one of the most commonly used vector control tools in the campaign against malaria. LLINs are effective only with proper use, adherence, retention and community adoption, which historically have relied on the successful control of secondary pests, including bed bugs. The emergence of pyrethroid-resistant bed bugs in malaria-endemic communities and failure to control infestations have been suggested to interfere with the effective use of LLINs. Therefore, the behavioral interactions of bed bugs with commonly used bed nets should be better understood.
METHODS: To investigate the interactions between bed bugs (Cimex lectularius L.) and LLINs, insecticide-susceptible and pyrethroid-resistant bed bugs were challenged to pass through two commonly used LLINs in two behavioral assays, namely host (blood meal)-seeking and aggregation-seeking assays. The proportions blood-fed and aggregated bed bugs, aggregation time and mortality were quantified and analyzed in different bed bug life stages.
RESULTS: Overall, both the insecticide-susceptible bed bugs and highly resistant bed bugs showed a varying ability to pass through LLINs based on treatment status and net design. Deltamethrin-treated nets significantly impeded both feeding and aggregation by the susceptible bed bugs. While none of the tested LLINs significantly impeded feeding (passage of unfed bed bugs through the nets) of the pyrethroid-resistant bed bugs, the untreated bed net, which has small mesh holes, impeded passage of fed bed bugs. Mortality was only seen in the susceptible bed bugs, with significantly higher mortality on deltamethrin-treated nets (63.5 ± 10.7%) than on permethrin-treated nets (2.0 ± 0.9%).
CONCLUSIONS: Commonly used new LLINs failed to prevent the passage of susceptible and pyrethroid-resistant bed bugs in host- and aggregation-seeking bioassays. The overall low and variable mortality observed in susceptible bed bugs during both assays highlighted the potential of LLINs to impose strong selection pressure for the evolution of pyrethroid resistance. Already, the failure to control bed bug infestations has been implicated as a contributing factor to the abandonment or misuse of LLINs. For the first time to our knowledge, we have shown the potential of LLINs in selecting for resistant secondary pest populations and so their potential role in stalling malaria control programs should be further investigated. The emergence of pyrethroid-resistant bed bugs in malaria-endemic communities may interfere with the effective use of pyrethroid-impregnated bed nets. We assessed the interactions of two bed bug strains with commonly used bed nets using two behavioral assays, namely host (blood meal)-seeking by unfed bed bugs and aggregation-seeking by freshly fed bed bugs. These assays assessed the passage of bed bugs through various bed nets in response to host cues and aggregation stimuli, respectively. Conditioned paper is a section of file folder paper that has been exposed to bed bugs and has been impregnated with feces and aggregation pheromone; it is attractive to aggregation-seeking fed bed bugs. An unconditioned ramp is a similar section of file folder paper that allows bed bugs to traverse the bed net and gain access to a blood-meal source.