Implications of bio-efficacy and persistence of insecticides when indoor residual spraying and long-lasting insecticide nets are combined for malaria prevention.
Implications of bio-efficacy and persistence of insecticides when indoor residual spraying and long-lasting insecticide nets are combined for malaria prevention.
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DOI：
10.1186/1475-2875-11-378
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发表时间：
2012-11-19
期刊：
影响因子：
3
通讯作者：
Moore SJ
中科院分区：
文献类型：
--
作者：
Okumu FO;Chipwaza B;Madumla EP;Mbeyela E;Lingamba G;Moore J;Ntamatungro AJ;Kavishe DR;Moore SJ
评估了用于室内滞留喷洒和长效驱虫蚊帐的杀虫剂对坦桑尼亚东南部实验室饲养的和野生的疟疾病媒阿拉伯按蚊种群的生物效力和残留活性。研究结果的影响的背景下，潜在的协同作用和冗余的IRS和LLINs相结合。每月对三种长效杀虫剂（Olyset PermaNet 2.0和Icon Life）和三种室内滞留喷雾杀虫剂（2克/平方米甲基嘧啶、2克/平方米滴滴涕和0.03克/平方米氯氟氰菊酯，喷洒在实验小屋的泥墙和棕榈树天花板上）进行生物测定，为期六个月。试验使用易感的实验室饲养的安。在球果（网和IRS）或钢丝球（仅网）中暴露的阿拉伯树。使用WHO诊断浓度和敲低抗性（kdr）基因的PCR评估野生种群的易感性。室内滞留喷雾杀虫剂处理可杀死85%以上的棕榈树天花板上的蚊子和90%以上的泥墙上的蚊子，但除滴滴涕外，高达50%的毒性在1-3个月内衰减。6个月时，在涂有甲基抗蚜蝇胺、DDT和氯氟氰菊酯的天花板上，蚊虫死亡率分别为7.5%、42.5%和30.0%，而在涂有相同杀虫剂的土墙上，蚊虫死亡率分别为12.5%、36.0%和27.5%。在钢丝球试验中，PermaNet 2.0®试验的死亡率从第1个月的98.1%降至第6个月的92.6%，Icon Life®试验的死亡率从100%降至61.1%，Olyset®试验的死亡率从93.2%降至33.3%。在锥形生物测定中，PermaNet 2.0®的死亡率从第1个月的92.8%降低到第6个月的83.3%，Icon Life®从96.9%降低到43.80%，Olyset®从85.6%降低到14.6%。怀尔德安阿拉伯小蠊对DDT的敏感率为100%，对溴氰菊酯的敏感率为95.8%，对高效氯氟氰菊酯的敏感率为90.2%，对氯菊酯的敏感率为95.2%。未检测到kdr基因突变。在确保与处理过的表面充分接触的生物测定中，LLIN和IRS杀死了高比例的敏感AN。阿拉伯蚊，尽管这些效力对于长效杀虫剂逐渐衰减，对于IRS迅速衰减。因此，必须始终在喷洒过的房屋中添加完整的蚊帐，以保证即使在室内滞留喷雾剂腐烂之后也能提供保护，并确保室内滞留喷雾剂方案中的准确时间、质量控制和定期重新喷洒。相比之下，在有完整长效驱虫蚊帐的房屋中添加室内滞留喷雾杀虫剂不太可能比单独使用长效驱虫蚊帐提高保护效果，因为无法保证不进食的病媒会在喷洒的表面停留足够长的时间，而且室内滞留喷雾杀虫剂会迅速衰减。然而，有必要澄清这些影响使用的数据，从观察自由飞行的蚊子在小屋。的生理易感性。该地区的阿拉伯小蠊对滴滴涕的抵抗率仍为100%，但对拟除虫菊酯的抵抗率略有下降，因此需要警惕可能的耐药性传播。LLIN毒性的丧失，特别是Olyset®蚊帐，表明这些蚊帐对An提供的保护作用。arabiensis可能主要是由于物理叮咬预防而不是杀虫功效。
Bio-efficacy and residual activity of insecticides used for indoor residual spraying (IRS) and long-lasting insecticide nets (LLINs) were assessed against laboratory-reared and wild populations of the malaria vector, Anopheles arabiensis in south eastern Tanzania. Implications of the findings are examined in the context of potential synergies and redundancies where IRS and LLINs are combined. Bioassays were conducted monthly for six months on three LLIN types (Olyset® PermaNet 2.0®,and Icon Life®) and three IRS treatments (2 g/m2 pirimiphos-methyl, 2 g/m2 DDT and 0.03 g/m2 lambda-cyhalothrin, sprayed on mud walls and palm ceilings of experimental huts). Tests used susceptible laboratory-reared An. arabiensis exposed in cones (nets and IRS) or wire balls (nets only). Susceptibility of wild populations was assessed using WHO diagnostic concentrations and PCR for knock-down resistance (kdr) genes. IRS treatments killed ≥ 85% of mosquitoes exposed on palm ceilings and ≥ 90% of those exposed on mud walls, but up to 50% of this toxicity decayed within 1–3 months, except for DDT. By 6th month, only 7.5%, 42.5% and 30.0% of mosquitoes died when exposed to ceilings sprayed with pirimiphos-methyl, DDT or lambda-cyhalothrin respectively, while 12.5%, 36.0% and 27.5% died after exposure to mud walls sprayed with the same insecticides. In wire-ball assays, mortality decreased from 98.1% in 1st month to 92.6% in 6th month in tests on PermaNet 2.0®, from 100% to 61.1% on Icon Life® and from 93.2% to 33.3% on Olyset® nets. In cone bioassays, mortality reduced from 92.8% in 1st month to 83.3% in 6th month on PermaNet 2.0®, from 96.9% to 43.80% on Icon Life® and from 85.6% to 14.6% on Olyset®. Wild An. arabiensis were 100% susceptible to DDT, 95.8% to deltamethrin, 90.2% to lambda cyhalothrin and 95.2% susceptible to permethrin. No kdr gene mutations were detected. In bioassays where sufficient contact with treated surfaces is assured, LLINs and IRS kill high proportions of susceptible An. arabiensis mosquitoes, though these efficacies decay gradually for LLINs and rapidly for IRS. It is, therefore, important to always add intact nets in sprayed houses, guaranteeing protection even after the IRS decays, and to ensure accurate timing, quality control and regular re-spraying in IRS programmes. By contrast, adding IRS in houses with intact LLINs is unlikely to improve protection relative to LLINs alone, since there is no guarantee that unfed vectors would rest long enough on the sprayed surfaces, and because of the rapid IRS decay. However, there is need to clarify these effects using data from observations of free flying mosquitoes in huts. Physiological susceptibility of An. arabiensis in the area remains 100% against DDT, but is slightly reduced against pyrethroids, necessitating caution over possible spread of resistance. The loss of LLIN toxicity, particularly Olyset® nets suggests that protection offered by these nets against An. arabiensis may be primarily due to physical bite prevention rather than insecticidal efficacy.