National Arbovirus and Vectors Research Centre (NAVRC), Enugu, Nigeria.
Department of Biological Sciences, Kogi State University, Anyigba, Nigeria.
Parasit Vectors. 2020 Mar 24;13(1):152. doi: 10.1186/s13071-020-04027-z.
Progress made in the control of malaria vectors globally is largely due to the use of insecticides. However, success in the fight against malaria has slowed down or even stalled due to a host of factors including insecticide resistance. The greatest burden of the disease is felt in Africa, particularly Nigeria. Unfortunately, adequate information on insecticide resistance is lacking in many parts of the country, particularly the South-East Zone. Hence, this study aims to bridge the information gap in the Zone.
The study was conducted from April to December 2016. Anopheles gambiae (s.l.) larvae and pupae were collected from one community each, in the five states of the South-East Zone and reared to the adult stage. The adults were subjected to bioassays for insecticide resistance in accordance with the World Health Organization test procedures, across the four classes of insecticides used in public health. The mosquitoes were also subjected to molecular identification to the species level, and genotyped for West African knockdown resistance mutation (L1014F) and insensitive acetylcholinesterase-1 resistance mutation (G119S).
The mosquitoes were susceptible (100%) to bendiocarb but resistant to pirimiphos-methyl (39.6%), deltamethrin (57%) and dichlorodiphenyltrichloroethane (DDT) (13%). Molecular analysis revealed that only An. gambiae (sensu stricto) was found in all the states except for Ebonyi, where only Anopheles coluzzii was present. High frequencies (0.6-0.9) of the L1014F mutation were found across the zone. The L1014F mutation was significantly higher in An. gambiae (s.s.) than in An. coluzzii (P < 0.0001). A relatively low frequency (0.2) of the G119S mutation was found in An. coluzzii, and only in Ebonyi State.
The results show that mosquitoes collected from the South-East Zone of Nigeria were resistant to all insecticides used, except for bendiocarb. The presence of L1014F and G119S resistance mutations reported in this study calls for urgent attention to stop the growing threat of insecticide resistance in the country.
全球疟疾媒介控制取得的进展在很大程度上归功于杀虫剂的使用。然而，由于包括杀虫剂抗性在内的诸多因素，抗击疟疾的工作进展已经放缓甚至停滞。疾病的最大负担在非洲感受到，特别是尼日利亚。不幸的是，该国许多地区，特别是东南部地区缺乏有关杀虫剂抗性的充分信息。因此，本研究旨在弥合该地区的信息差距。
本研究于 2016 年 4 月至 12 月进行。从东南部五个州的每个社区收集按蚊（s.l.）幼虫和蛹，并将其饲养至成虫阶段。根据世界卫生组织的测试程序，对成虫进行了针对四类用于公共卫生的杀虫剂的抗药性生物测定。还对蚊子进行了种水平的分子鉴定，并对西非击倒抗性突变（L1014F）和乙酰胆碱酯酶-1 不敏感抗性突变（G119S）进行了基因分型。
蚊子对苯氧威（100％）敏感，但对吡虫啉（39.6％），溴氰菊酯（57％）和滴滴涕（DDT）（13％）有抗性。分子分析表明，除埃贝尼州外，所有州都只发现了冈比亚按蚊（s.s.），而在埃贝尼州只发现了斑须按蚊。整个区域都发现了 L1014F 突变的高频（0.6-0.9）。 L1014F 突变在冈比亚按蚊（s.s.）中明显高于斑须按蚊（P <0.0001）。在斑须按蚊中发现了相对较低的 G119S 突变频率（0.2），仅在埃贝尼州发现。
结果表明，从尼日利亚东南部地区采集的蚊子对除苯氧威以外的所有使用的杀虫剂均具有抗性。本研究报告的 L1014F 和 G119S 抗性突变的存在呼吁紧急关注，以阻止该国不断增长的杀虫剂抗性威胁。
