Bayili Koama, N'do Severin, Namountougou Moussa, Sanou Roger, Ouattara Abdoulaye, Dabiré Roch K, Ouédraogo Anicet G, Malone David, Diabaté Abdoulaye
Intitut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso.
Universite Polytechnique de Bobo, Bobo-Dioulasso, Burkina Faso.
Malar J. 2017 May 8;16(1):190. doi: 10.1186/s12936-017-1846-4.
Malaria vectors have acquired widespread resistance throughout sub-Saharan Africa to many of the currently used insecticides. Hence, there is an urgent need to develop alternative strategies including the development of new insecticides for effective management of insecticide resistance. To maintain progress against malaria, it is necessary to identify other residual insecticides for mosquito nets. In the present WHOPES phase II analogue study, the utility of chlorfenapyr, a pyrrole class insecticide mixed with alpha-cypermethrin on a long-lasting mosquito bed net was evaluated against Anopheles gambiae s.l.
Bed nets treated with chlorfenapyr and alpha-cypermethrin and mixture of both compounds were tested for their efficacy on mosquitoes. Washed (20 times) and unwashed of each type of treated nets and were tested according to WHOPES guidelines. Efficacy of nets were expressed in terms of blood-feeding inhibition rate, deterrence, induced exophily and mortality rate. The evaluation was conducted in experimental huts of Vallée du Kou seven (VK7) in Burkina Faso (West Africa) following WHOPES phase II guidelines. In addition, a WHOPES phase I evaluation was also performed.
Mixture treated nets killed significantly (P < 0.05) more mosquitoes than solo alpha-cypermethrin nets, unwashed and washed. Proportionally, this equated to mortalities of 78 and 76% (for mixture nets) compared to only 17 and 10% (for solo alpha-cypermethrin) to An. gambiae, respectively. In contrast mixture net proportions were not significantly (P > 0.05) different from nets treated with chlorfenapyr 200 mg/m unwashed (86%). The washed and unwashed nets treated with the mixtures resulted in personal protection against An. gambiae s.l. biting 34 and 44%. In contrast the personal protection observed for washed and unwashed alpha-cypermethrin treated nets generated (14 and 24%), and chlorfenapyr solo treated net was rather low (22%).
Among all nets trialled, the combination of chlorfenapyr and alpha-cypermethrin on bed nets provided better mortality in phase II after 20 washes. Results suggest that this combination could be a potential insecticide resistance management tool for preventing malaria transmission in areas compromised by the spread of pyrethroid resistance.
在撒哈拉以南非洲地区，疟疾媒介已对许多目前使用的杀虫剂产生了广泛抗性。因此，迫切需要制定替代策略，包括开发新的杀虫剂以有效管理杀虫剂抗性。为保持在抗击疟疾方面取得的进展，有必要确定用于蚊帐的其他残留杀虫剂。在目前的世卫组织疟疾防治和病媒控制合作中心（WHOPES）第二阶段类似物研究中，评估了吡咯类杀虫剂氯虫苯甲酰胺与α-氯氰菊酯混合在长效蚊帐上对冈比亚按蚊复合组的效用。
对用氯虫苯甲酰胺、α-氯氰菊酯以及两种化合物混合物处理过的蚊帐进行了蚊虫防治效果测试。每种处理过的蚊帐都经过洗涤（20次）和未洗涤处理，并按照WHOPES指南进行测试。蚊帐的防治效果以吸血抑制率、驱避率、诱使外栖率和死亡率来表示。评估是在布基纳法索（西非）瓦莱杜库7号（VK7）的实验小屋中按照WHOPES第二阶段指南进行的。此外，还进行了一次WHOPES第一阶段评估。
与单独使用α-氯氰菊酯的未洗涤和洗涤过的蚊帐相比，混合物处理过的蚊帐杀死的蚊子显著更多（P < 0.05）。按比例计算，这相当于混合物蚊帐对冈比亚按蚊的死亡率分别为78%和76%，而单独使用α-氯氰菊酯的蚊帐死亡率仅为17%和10%。相比之下，混合物蚊帐的比例与未洗涤的200毫克/平方米氯虫苯甲酰胺处理过的蚊帐（86%）没有显著差异（P > 0.05）。用混合物处理过的洗涤和未洗涤蚊帐对冈比亚按蚊复合组叮咬的个人防护率分别为34%和44%。相比之下，观察到的洗涤和未洗涤的α-氯氰菊酯处理过的蚊帐的个人防护率分别为14%和24%，而单独使用氯虫苯甲酰胺处理过的蚊帐的个人防护率相当低（22%）。
在所有试验的蚊帐中，氯虫苯甲酰胺和α-氯氰菊酯在蚊帐上的组合在洗涤20次后的第二阶段提供了更好的死亡率。结果表明，这种组合可能是一种潜在的杀虫剂抗性管理工具，用于在受拟除虫菊酯抗性传播影响的地区预防疟疾传播。
