Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), P.O. Box 288, Yaoundé, Cameroon.
Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.
Parasit Vectors. 2022 Jun 2;15(1):186. doi: 10.1186/s13071-022-05321-8.
The practice of agriculture in urban settings contributes to the rapid expansion of insecticide resistance in malaria vectors. However, there is still not enough information on pesticide usage in most urban settings. The present study aims to assess the evolution of Anopheles gambiae (s.l.) population susceptibility to insecticides and patterns of pesticide usage in agriculture in the city of Yaoundé, Cameroon.
WHO susceptibility tests and synergist PBO bioassays were conducted on adult An. gambiae (s.l.) mosquitoes aged 3 to 5 days emerging from larvae collected from the field. Seven insecticides (deltamethrin, permethrin, DDT, bendiocarb, propoxur, fenitrothion and malathion) were evaluated. The presence of target site mutation conferring knockdown (kdr) resistance was investigated using TaqMan assay, and mosquito species were identified using SINE-PCR. Surveys on 81 retailers and 232 farmers were conducted to assess general knowledge and practices regarding agricultural pesticide usage.
High resistance intensity to pyrethroids was observed with a high frequency of the kdr allele 1014F and low frequency of the kdr 1014S allele. The level of susceptibility of An. gambiae (s.l.) to pyrethroids and carbamates was found to decrease with time (from > 34% in 2017 to < 23% in 2019 for deltamethrin and permethrin and from 97% in 2017 to < 86% in 2019 for bendiocarb). Both An. gambiae (s.s.) and An. coluzzii were recorded. Over 150 pesticides and fertilizers were sold by retailers for agricultural purposes in the city of Yaoundé. Most farmers do not respect safety practices. Poor practices including extensive and inappropriate application of pesticides as well as poor management of perished pesticides and empty pesticide containers were also documented.
The study indicated rapid evolution of insecticide resistance and uncontrolled usage of pesticides by farmers in agriculture. There is an urgent need to address these gaps to improve the management of insecticide resistance.
城市农业实践导致疟疾传播媒介对杀虫剂的抗药性迅速扩大。然而，大多数城市环境中关于农药使用的信息仍然不足。本研究旨在评估喀麦隆雅温得市按蚊种群对杀虫剂的敏感性变化和农业中农药使用模式。
对从田间采集的 3 至 5 天龄幼虫中出现的成蚊进行了 WHO 敏感性测试和增效剂 PBO 生物测定。评估了 7 种杀虫剂（溴氰菊酯、氯菊酯、滴滴涕、丁醚脲、残杀威、杀螟硫磷和马拉硫磷）。使用 TaqMan 检测法调查了导致击倒（kdr）抗性的靶位突变的存在情况，使用 SINE-PCR 鉴定了蚊子种类。对 81 名零售商和 232 名农民进行了调查，以评估他们对农业农药使用的一般知识和实践情况。
对拟除虫菊酯表现出高抗性强度，kdr 等位基因 1014F 的频率很高，而 kdr 1014S 等位基因的频率较低。按蚊（s.l.）对拟除虫菊酯和氨基甲酸酯的敏感性水平随时间而降低（2017 年氯菊酯和溴氰菊酯的敏感性水平>34%，2019 年降至<23%，2017 年丁醚脲的敏感性水平为 97%，2019 年降至<86%）。记录到冈比亚按蚊（s.s.）和库蚊（An. coluzzii）。零售商为城市农业销售了 150 多种农药和化肥。大多数农民不遵守安全操作规程。还记录了不良做法，包括广泛和不适当的农药使用以及对过期农药和空农药容器的管理不善。
该研究表明，昆虫对杀虫剂的抗药性迅速演变，农民在农业中对农药的使用不受控制。迫切需要解决这些差距，以改善对杀虫剂抗药性的管理。
