Kiuru Caroline, Constantino Luis, Cole Gildo, Karisa Jonathan, Wanjiku Caroline, Okoko Miguel, Candrinho Baltazar, Saute Francisco, Rabinovich N Regina, Chaccour Carlos, Maia Marta Ferreira
Centro de Investigação Em Saúde de Manhiça (CISM), Maputo, Mozambique.
Barcelona Institute for Global Health (Isglobal), Barcelona, Spain.
Malar J. 2025 Mar 14;24(1):81. doi: 10.1186/s12936-025-05321-w.
The main malaria vector control methods implemented in Mozambique are insecticide-treated nets (ITN's) and indoor residual spraying (IRS). These insecticide-based interventions are currently threatened by the rapidly spreading insecticide resistance in several major malaria vectors. Monitoring of insecticide resistance is necessary to inform the selection of insecticides by control programmes. This study describes the insecticide resistance profiles of the main malaria vector, Anopheles funestus sensu lato. in Mopeia district, a malaria holoendemic area of the Zambezia province of Mozambique.
Anopheles adults and larvae were collected from 15 sentinel sites across the district between October 2021 and September 2022. Wild-caught, unfed female adults were collected using CDC-light traps and pooled over three days before exposure to the test insecticide. For mosquitoes collected as larvae, F0 adults aged 3-5 days post-emergence were used for insecticide susceptibility testing. Resistance to bendiocarb, DDT, deltamethrin and pirimiphos-methyl was evaluated using the standard WHO tube bioassay. The mechanism of resistance was probed using the PBO (piperonyl butoxide) synergistic bioassay. The presence and frequency of different genetic mutations associated with insecticide resistance was assessed using polymerase chain reaction, including A296S-Rdl, L119F-GSTe2 and 6.5 kb SV (structural variation) insertion.
A total of 1349 female Anopheles mosquitoes (controls included) were used for susceptibility tests with discriminating insecticide concentrations. Phenotypic resistance to bendiocarb, DDT, deltamethrin and pirimiphos-methyl was observed, with 37%, 79%, 14% and 67% mortality rate respectively. Pre-exposure to PBO partially restored susceptibility to deltamethrin to a mortality rate of 80%. The frequency of the insecticide resistance mutations was 0.49, 0.05 and 0.92, for A296S-Rdl, L119F-GSTe2 and 6.5 kb SV insertion, respectively.
Malaria vectors in Mopeia exhibit resistance to all four major public health insecticide classes: pyrethroids, organophosphates, organochlorides and carbamates. This highlights the urgent need to adopt new insecticide classes for vector control interventions. The partial restoration of susceptibility by PBO suggests resistance is being driven by various mechanisms including the involvement of metabolic resistance through cytochrome P450 monooxygenase enzymes and glutathione S-transferases.
莫桑比克实施的主要疟疾媒介控制方法是经杀虫剂处理的蚊帐（ITN）和室内滞留喷洒（IRS）。这些基于杀虫剂的干预措施目前正受到几种主要疟疾媒介中迅速蔓延的杀虫剂抗性的威胁。监测杀虫剂抗性对于指导控制项目选择杀虫剂至关重要。本研究描述了莫桑比克赞比西亚省疟疾高度流行地区莫佩亚区主要疟疾媒介嗜人按蚊复合组的杀虫剂抗性概况。
2021年10月至2022年9月期间，从该地区的15个哨点收集了按蚊成虫和幼虫。使用疾控中心诱蚊灯诱捕野生未进食的雌蚊，并在暴露于测试杀虫剂前三天将其合并。对于作为幼虫收集的蚊子，羽化后3至5天的F0代成虫用于杀虫剂敏感性测试。使用标准的世卫组织试管生物测定法评估对残杀威、滴滴涕、溴氰菊酯和甲基嘧啶磷的抗性。使用增效醚（胡椒基丁醚）增效生物测定法探究抗性机制。使用聚合酶链反应评估与杀虫剂抗性相关的不同基因突变的存在和频率，包括A296S-Rdl、L119F-GSTe2和6.5 kb结构变异（SV）插入。
总共1349只雌性按蚊（包括对照）用于区分杀虫剂浓度的敏感性测试。观察到对残杀威、滴滴涕、溴氰菊酯和甲基嘧啶磷的表型抗性，死亡率分别为37%、79%、14%和67%。预先接触增效醚后，对溴氰菊酯的敏感性部分恢复，死亡率达到80%。A296S-Rdl、L119F-GSTe2和6.5 kb SV插入的杀虫剂抗性突变频率分别为0.49、0.05和0.92。
莫佩亚的疟疾媒介对所有四类主要公共卫生杀虫剂均表现出抗性：拟除虫菊酯类、有机磷类、有机氯类和氨基甲酸酯类。这突出表明迫切需要采用新的杀虫剂类别用于媒介控制干预措施。增效醚使敏感性部分恢复，这表明抗性是由多种机制驱动的，包括通过细胞色素P450单加氧酶和谷胱甘肽S-转移酶参与代谢抗性。
