Département des Sciences de la Vie et de la Terre, Ecole Normale Supérieure de Natitingou, Natitingou, Bénin.
Plateforme Agriculture Environnement Santé, Institut International d'Agriculture Tropicale (IITA-Bénin), Cotonou, Bénin.
BMC Infect Dis. 2024 May 30;24(1):545. doi: 10.1186/s12879-024-09440-8.
This study aimed to investigate the relationship between the physicochemical characteristics of An. gambiae s.s. and An. coluzzii breeding sites, the susceptibility profiles to commonly used insecticides in public health, and the underlying insecticide resistance mechanisms.
Anopheles breeding sites surveys were conducted in Cotonou and Natitingou in September 2020, January and August 2021. Physicochemical properties and bacterial loads were determined in individual breeding sites. The WHO susceptibility assays were carried out using the female of the emerging adult mosquitoes. Anopheles species were identified through PCR techniques. Kdr L1014F/S, N1575Y and G119S mutations were investigated using TaqMan genotyping assays.
Molecular analysis showed that all mosquitoes analyzed in Cotonou were Anopheles coluzzii, while those of Natitingou were Anopheles gambiae s.s. Fecal coliforms were identified as playing a role in this distribution through their significant influence on the presence of An. coluzzii larvae. WHO susceptibility assay indicated a high level of resistance to deltamethrin in the two cities. The resistance levels to deltamethrin were higher in Cotonou (X = 31.689; DF = 1; P < 0.0001). There was a suspected resistance to bendiocarb in Cotonou, whereas the mosquito population in Natitingou was resistant. The kdr L1014F mutation was highly observed in both mosquito populations (frequence: 86-91%), while the Ace-1 mutation was found in a small proportion of mosquitoes. In Cotonou, salinity was the only recorded physicochemical parameter that significantly correlated with the resistance of Anopheles mosquitoes to deltamethrin (P < 0.05). In Natitingou, significant correlations were observed between the allelic frequencies of the kdr L1014F mutation and pH, conductivity, and TDS.
These results indicate a high level of pyrethroid resistance in the anopheles populations of both Cotonou and Natitingou. Moreover, this study report the involvement of abiotic factors influencing Anopheles susceptibility profile.
本研究旨在探讨冈比亚按蚊和库蚊滋生地的理化特性、对公共卫生常用杀虫剂的敏感性谱以及潜在的杀虫剂抗性机制之间的关系。
2020 年 9 月、2021 年 1 月和 8 月在科托努和纳蒂廷戈进行了按蚊滋生地调查。在单个滋生地中测定了理化性质和细菌负荷。使用新出现的成年雌蚊进行了世界卫生组织（WHO）敏感性测定。通过聚合酶链反应（PCR）技术鉴定按蚊种。使用 TaqMan 基因分型测定法研究了 kdr L1014F/S、N1575Y 和 G119S 突变。
分子分析表明，在科托努分析的所有蚊子均为库蚊，而纳蒂廷戈的蚊子为冈比亚按蚊。粪便大肠菌群通过对库蚊幼虫存在的显著影响，被确定在这种分布中起作用。在这两个城市，对溴氰菊酯的敏感性测试表明存在高水平的抗性。科托努的溴氰菊酯抗性水平更高（X=31.689；DF=1；P<0.0001）。在科托努疑似对苯氧威有抗性，而纳蒂廷戈的蚊子种群则有抗性。kdr L1014F 突变在两个蚊子种群中均高度存在（频率：86-91%），而 Ace-1 突变在一小部分蚊子中存在。在科托努，盐度是唯一记录到的与按蚊对溴氰菊酯抗性显著相关的理化参数（P<0.05）。在纳蒂廷戈，kdr L1014F 突变的等位基因频率与 pH、电导率和总溶解固体（TDS）之间存在显著相关性。
这些结果表明，科托努和纳蒂廷戈的按蚊种群对拟除虫菊酯的抗性水平很高。此外，本研究报告了非生物因素对按蚊敏感性谱的影响。
