Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Pembroke Place, L3 5QA, United Kingdom.
Department of Biochemistry, Bayero University, PMB 3011, Kano, Nigeria.
Sci Rep. 2019 May 14;9(1):7395. doi: 10.1038/s41598-019-43634-4.
Despite the highest global burden of malaria, information on bionomics and insecticide resistance status of malaria vectors is grossly lacking in the densely populated Sahelo-Sudanian region of Nigeria. To support evidence-based vector control we characterised transmission and resistance profiles of Anopheles coluzzii populations from three sites in northern Nigeria. High sporozoite infection (~19.51%) was found in the An. coluzzii populations. A high pyrethroid resistance was observed with only 1% mortality against deltamethrin, a high LD (96.57 µg/ml), and a high LT (170.27 min, resistance ratio of ~51 compared with the fully susceptible Ngoussou colony). Moderate carbamate resistance was observed. Synergist bioassays significantly recovered deltamethrin susceptibility implicating CYP450s (mortality = 85%, χ = 134.04, p < 0.0001) and esterases (mortality = 56%, χ = 47.31, p < 0.0001). Reduced bed net efficacy was also observed, with mortalities on exposure to the roof of PermaNet3.0 (PBO + deltamethrin) more than 22 times compared to the side panel (deltamethrin). TaqMan genotyping revealed a high frequency of 1014F kdr mutation (82%) with significant difference in genotype distribution associated with permethrin resistance [OR = 4.69 (CI:1.53-14.35, χ = 8.22 p = 0.004]. Sequencing of exons 18-21 of the VGSC led to detection of two additional nonsynonymous mutations, Ile10148Asn and Ser1156Gly. These findings highlight the threats posed by the highly resistant An. coluzzii to malaria control in Nigeria.
尽管疟疾在全球的负担最重，但在尼日利亚人口稠密的萨赫勒-苏丹地区，有关疟疾媒介的生物生态学和抗药性现状的信息却严重缺乏。为了支持基于证据的病媒控制，我们对来自尼日利亚北部三个地点的斑蚊种群的传播和抗药性特征进行了描述。在斑蚊种群中发现了高疟原虫感染率（约 19.51%）。对氯菊酯表现出很高的抗药性，死亡率仅为 1%，LD 很高（96.57 µg/ml），LT 也很高（170.27 分钟，与完全敏感的 Ngoussou 品系相比，抗性比约为 51）。还观察到中等程度的氨基甲酸酯抗性。增效剂生物测定显著恢复了氯菊酯的敏感性，表明与 CYP450s（死亡率=85%，χ=134.04，p<0.0001）和酯酶（死亡率=56%，χ=47.31，p<0.0001）有关。还观察到蚊帐效果降低，与暴露在 PermaNet3.0（PBO+氯菊酯）屋顶相比，死亡率超过侧面（氯菊酯）的 22 倍。TaqMan 基因分型显示 1014F kdr 突变的高频率（82%），与与拟除虫菊酯抗性相关的基因型分布存在显著差异[OR=4.69（CI：1.53-14.35，χ=8.22 p=0.004]。对 VGSC 的外显子 18-21 进行测序，检测到另外两个非同义突变，Ile10148Asn 和 Ser1156Gly。这些发现强调了高度耐药的斑蚊对尼日利亚疟疾控制构成的威胁。
