Nkemngo Francis N, Mugenzi Leon M J, Terence Ebai, Niang Abdoulaye, Wondji Murielle J, Tchoupo Micareme, Nguete Nguiffo D, Tchapga Williams, Irving Helen, Ntabi Jacques D M, Agonhossou Romuald, Boussougou-Sambe Terence S, Akoton Romaric B, Koukouikila-Koussounda Felix, Pinilla Yudi T, Ntoumi Francine, Djogbenou Luc S, Ghogomu Stephen M, Ndo Cyrille, Adegnika Ayola A, Borrmann Steffen, Wondji Charles S
Department of Parasitology and Medical Entomology, Centre for Research in Infectious Diseases (CRID), Yaounde, Centre Region, 237, Cameroon.
Department of Microbiology and Parasitology, University of Buea, Buea, South West, 237, Cameroon.
Wellcome Open Res. 2020 Nov 5;5:146. doi: 10.12688/wellcomeopenres.15818.2. eCollection 2020.
Reducing the burden of malaria requires better understanding of vector populations, particularly in forested regions where the incidence remains elevated. Here, we characterized malaria vectors in a locality near the Yaoundé international airport, Cameroon, including species composition, abundance, infection rate, insecticide resistance profiles and underlying resistance mechanisms. Blood-fed adult mosquitoes resting indoors were aspirated from houses in April 2019 at Elende, a locality situated 2 km from the Yaoundé-Nsimalen airport. Female mosquitoes were forced to lay eggs to generate F adults. Bioassays were performed to assess resistance profile to the four insecticides classes. The threshold of insecticide susceptibility was defined above 98% mortality rate and mortality rates below 90% were indicative of confirmed insecticide resistance. Furthermore, the molecular basis of resistance and infection rates were investigated. s.s. was the most abundant species in Elende (85%) followed by s.s. (15%) with both having similar sporozoite rate. Both species exhibited high levels of resistance to the pyrethroids, permethrin and deltamethrin (<40% mortality). s.s. was resistant to DDT (9.9% mortality) and bendiocarb (54% mortality) while susceptible to organophosphate. s.s. was resistant to dieldrin (1% mortality), DDT (86% mortality) but susceptible to carbamates and organophosphates. The L119F-GSTe2 resistance allele (8%) and G119S -1 resistance allele (15%) were detected in s.s. and s.s., respectively Furthermore, the high pyrethroid/DDT resistances in corresponded with an increase frequency of 1014F allele (95%). Transcriptional profiling of candidate cytochrome P450 genes reveals the over-expression of , and The resistance to multiple insecticide classes observed in these vector populations alongside the significant sporozoite rate highlights the challenges that vector control programs encounter in sustaining the regular benefits of contemporary insecticide-based control interventions in forested areas.
减轻疟疾负担需要更好地了解病媒种群，特别是在发病率仍然较高的森林地区。在此，我们对喀麦隆雅温得国际机场附近一个地点的疟疾传播媒介进行了特征分析，包括种类组成、丰度、感染率、杀虫剂抗性概况及潜在的抗性机制。2019年4月，在距离雅温得-恩西马伦机场2公里的埃伦德地区，从室内休息的血饲成年蚊子中采集样本。迫使雌蚊产卵以产生F代成虫。进行生物测定以评估对四类杀虫剂的抗性概况。杀虫剂易感性阈值定义为死亡率高于98%，死亡率低于90%表明存在确诊的杀虫剂抗性。此外，还研究了抗性的分子基础和感染率。在埃伦德地区，冈比亚按蚊是最丰富的物种（85%），其次是阿拉伯按蚊（15%），两者的子孢子率相似。两种物种对拟除虫菊酯类杀虫剂氯菊酯和溴氰菊酯均表现出高抗性（死亡率<40%）。冈比亚按蚊对滴滴涕（死亡率9.9%）和残杀威（死亡率54%）具有抗性，但对有机磷敏感。阿拉伯按蚊对狄氏剂（死亡率1%）、滴滴涕（死亡率86%）具有抗性，但对氨基甲酸酯类和有机磷类敏感。分别在冈比亚按蚊和阿拉伯按蚊中检测到L119F-GSTe2抗性等位基因（8%）和G119S-1抗性等位基因（15%）。此外，冈比亚按蚊对拟除虫菊酯/滴滴涕的高抗性与1014F等位基因频率的增加（95%）相对应。候选细胞色素P450基因的转录谱分析显示，CYP6P9a、CYP6P9b和CYP6M2过度表达。在这些病媒种群中观察到的对多种杀虫剂类别的抗性以及显著的子孢子率突出了病媒控制项目在维持森林地区当代基于杀虫剂的控制干预措施的常规效益方面所面临的挑战。
