Faculté des Sciences et Techniques de l'Université d'Abomey Calavi, Calavi, Bénin.
Parasit Vectors. 2012 Apr 10;5:72. doi: 10.1186/1756-3305-5-72.
In Benin, Indoor Residual Spraying (IRS) and long-lasting insecticidal nets (LLINs) are the cornerstones of malaria prevention. In the context of high resistance of Anopheles gambiae to pyrethroids, The National Malaria Control Program (NMCP) has undertaken a full coverage of IRS in a no-flood zone in the Oueme region, coupled with the distribution of LLINs in a flood zone. We assessed the impact of this campaign on phenotypic resistance, kdr (knock-down resistance) and ace-1(R) (insensitive acetylcholinesterase) mutations.
Insecticides used for malaria vector control interventions were bendiocarb WP (0.4 g/m²) and deltamethrin (55 mg/m²), respectively for IRS and LLINs. Susceptibility status of An. gambiae was assessed using World Health Organization bioassay tests to DDT, permethrin, deltamethrin and bendiocarb in the Oueme region before intervention (2007) and after interventions in 2008 and 2010. An. gambiae specimens were screened for identification of species, molecular M and S forms and for the detection of the West African kdr (L1014F) as well as ace-1(R) mutations using PCR techniques.
The univariate logistic regression performed showed that kdr frequency has increased significantly during the three years in the intervention area and in the control area. Several factors (LLINs, IRS, mosquito coils, aerosols, use of pesticides for crop protection) could explain the selection of individual resistant An. gambiae. The Kdr resistance gene could not be the only mechanism of resistance observed in the Oueme region. The high susceptibility to bendiocarb is in agreement with a previous study conducted in Benin. However, the occurrence of ace-1(R) heterozygous individuals even on sites far from IRS areas, suggests other factors may contribute to the selection of resistance other than those exerted by the vector control program.
The results of this study have confirmed that An.gambiae have maintained and developed the resistance to pyrethroids, but are still susceptible to bendiocarb. Our data clearly shows that selection of resistant individuals was caused by other insecticides than those used by the IRS and LLINs.
在贝宁，室内滞留喷洒（IRS）和长效驱虫蚊帐（LLIN）是预防疟疾的基石。在冈比亚按蚊对拟除虫菊酯高度耐药的情况下，国家疟疾控制规划（NMCP）在乌埃姆地区的无洪水区全面开展 IRS，并在洪水区发放 LLIN。我们评估了该运动对表型抗性、kdr（击倒抗性）和 ace-1（R）（不敏感乙酰胆碱酯酶）突变的影响。
用于疟疾媒介控制干预的杀虫剂分别为 bendiocarb WP（0.4 g/m²）和氯菊酯（55 mg/m²），分别用于 IRS 和 LLIN。在干预前（2007 年）和干预后（2008 年和 2010 年），在乌埃姆地区使用世界卫生组织生物测定试验评估冈比亚按蚊的敏感性状态，评估对滴滴涕、氯菊酯、氯菊酯和 bendiocarb 的敏感性。冈比亚按蚊标本经鉴定为种、分子 M 和 S 形式，并通过 PCR 技术检测西非 kdr（L1014F）和 ace-1（R）突变。
进行的单变量逻辑回归显示，在干预区和对照区，三年来 kdr 频率显著增加。多种因素（LLINs、IRS、蚊香、气雾剂、作物保护用农药）可解释个体抗性冈比亚按蚊的选择。Kdr 抗性基因可能不是在乌埃姆地区观察到的唯一抗性机制。对 bendiocarb 的高敏感性与之前在贝宁进行的一项研究一致。然而，即使在远离 IRS 区域的地点也发现 ace-1（R）杂合个体的存在，表明除了由蚊虫控制计划施加的因素外，其他因素可能有助于抗性的选择。
本研究结果证实，冈比亚按蚊对拟除虫菊酯的抗性得到维持和发展，但仍对 bendiocarb 敏感。我们的数据清楚地表明，抗性个体的选择是由 IRS 和 LLIN 以外的其他杀虫剂引起的。
