Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), United Kingdom.
Centre for Research in Infectious Diseases (CRID), Yaoundé, Cameroon.
J Infect Dis. 2019 Jul 2;220(3):467-475. doi: 10.1093/infdis/jiz139.
Insecticide resistance poses a serious threat to insecticide-based interventions in Africa. There is a fear that resistance escalation could jeopardize malaria control efforts. Monitoring of cases of aggravation of resistance intensity and its impact on the efficacy of control tools is crucial to predict consequences of resistance.
The resistance levels of an Anopheles funestus population from Palmeira, southern Mozambique, were characterized and their impact on the efficacy of various insecticide-treated nets established.
A dramatic loss of efficacy of all long-lasting insecticidal nets (LLINs), including piperonyl butoxide (PBO)-based nets (Olyset Plus), was observed. This An. funestus population consistently (2016, 2017, and 2018) exhibited a high degree of pyrethroid resistance. Molecular analyses revealed that this resistance escalation was associated with a massive overexpression of the duplicated cytochrome P450 genes CYP6P9a and CYP6P9b, and also the fixation of the resistance CYP6P9a_R allele in this population in 2016 (100%) in contrast to 2002 (5%). However, the low recovery of susceptibility after PBO synergist assay suggests that other resistance mechanisms could be involved.
The loss of efficacy of pyrethroid-based LLINs with and without PBO is a concern for the effectiveness of insecticide-based interventions, and action should be taken to prevent the spread of such super-resistance.
杀虫剂耐药性对非洲基于杀虫剂的干预措施构成严重威胁。人们担心耐药性升级可能会危及疟疾控制工作。监测耐药性强度加剧的情况及其对控制工具效果的影响对于预测耐药性的后果至关重要。
对莫桑比克南部帕尔梅拉的致倦库蚊种群的抗药性水平进行了特征描述，并确定了其对各种经杀虫剂处理的蚊帐（包括增效型氯菊酯蚊帐 Olyset Plus）效果的影响。
所有长效杀虫剂处理蚊帐（LLINs）的效果均明显下降，包括增效醚处理的蚊帐。这种致倦库蚊种群一直表现出高度的拟除虫菊酯抗性（2016 年、2017 年和 2018 年）。分子分析表明，这种耐药性升级与重复的细胞色素 P450 基因 CYP6P9a 和 CYP6P9b 的大量过度表达以及该种群中抗性 CYP6P9a_R 等位基因的固定有关，而在 2016 年（100%），这种等位基因在 2002 年（5%）的固定率较低。然而，增效醚试验后对敏感性的低恢复表明可能存在其他耐药机制。
无增效醚和有增效醚的拟除虫菊酯类 LLINs 的效果丧失令人担忧，可能会影响基于杀虫剂的干预措施的效果，应采取行动防止这种超级耐药性的传播。
