Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran.
Department of Vector-Borne Diseases, Centre for Communicable Diseases Control, Ministry of Health, Tehran, Iran.
Trop Med Int Health. 2024 Sep;29(9):781-791. doi: 10.1111/tmi.14028. Epub 2024 Jul 31.
Anopheles stephensi, a malaria-transmitting mosquito species, has developed resistance to various insecticides such as DDT, Dieldrin, Malathion, and synthetic pyrethroids. To combat this issue, the World Health Organization (WHO) suggests using Actellic®300CS and Icon®10CS for Indoor Residual Spraying to tackle pyrethroid-resistant mosquitoes. The aim of this research project was to evaluate the susceptibility of An. stephensi to certain insecticides at the diagnostic concentration + intensity 5x diagnostic concentration (5XDC) assays in Iran and to study the lasting effectiveness of Actellic®300CS and Icon®10CS against this particular malaria vector.
This study assessed the susceptibility of An. stephensi populations in southern Iran to various insecticides, including deltamethrin 0.05%, DDT 4%, malathion 5%, bendiocarb 0.1%, a synergist assay with PBO 4% combined with deltamethrin 0.05%, and an intensity assay using 5x the diagnostic concentration of deltamethrin (0.25%) and bendiocarb 0.5%. Laboratory cone bioassay tests were conducted to determine the residual effectiveness of Actellic®300 and Icon®10CS insecticides on different surfaces commonly found in households, such as cement, mud, plaster, and wood. The tests were carried out following the WHO test kits and standard testing protocols.
The An. stephensi populations in Bandar Abbas were found to be susceptible to malathion 5% and deltamethrin 0.25% (5XDC), but exhibited resistance to DDT, standard concentration of deltamethrin, and both standard and intensity concentrations of bendiocarb. In laboratory cone bioassay tests, An. stephensi mortality rates when exposed to Actellic®300CS and Icon®10CS on different surfaces remained consistently more than 80%. Actellic®300CS achieved more than 80% mortality on all substrates for the entire 300-day post-spraying period. Conversely, Icon®10CS maintained mortality rates more than 80% on plaster and wood surfaces for 165 days and on mud and cement surfaces for 270 days post-spraying. Both Actellic®300CS and Icon®10CS demonstrated 100% mortality within 72 h of each test on all surfaces throughout the entire 300-day post-spraying period.
The study shows the varying levels of resistance of An. stephensi Bandar Abbas population to different insecticides and demonstrates the consistent performance of Actellic®300CS in controlling these mosquitoes on various surfaces. The findings suggest that long-lasting CS formulations may be more effective for malaria vector control compared to the current options. Further research is needed to validate these findings in field settings and assess the impact of these insecticides on malaria transmission.
致倦库蚊已对滴滴涕、狄氏剂、马拉硫磷和合成拟除虫菊酯等多种杀虫剂产生抗药性。为了解决这个问题，世界卫生组织（WHO）建议使用 Actellic®300CS 和 Icon®10CS 进行室内滞留喷洒，以应对对拟除虫菊酯产生抗药性的蚊子。本研究项目旨在评估伊朗致倦库蚊种群对某些杀虫剂的敏感性，即在诊断浓度+强度 5 倍诊断浓度（5XDC）检测中，研究 Actellic®300CS 和 Icon®10CS 对这种特定疟疾传播媒介的持续有效性。
本研究评估了伊朗南部致倦库蚊种群对包括溴氰菊酯 0.05%、滴滴涕 4%、马拉硫磷 5%、丁醚脲 0.1%、增效剂 PBO 4%与溴氰菊酯 0.05%混合物以及诊断浓度 5 倍的溴氰菊酯（0.25%）和丁醚脲 0.5%的强度检测在内的各种杀虫剂的敏感性。采用实验室锥形生物测定试验，确定 Actellic®300 和 Icon®10CS 杀虫剂在家庭中常见的不同表面（如水泥、泥土、灰泥和木材）上的残留效果。试验按照世界卫生组织的试验试剂盒和标准测试方案进行。
研究发现，阿巴斯港的致倦库蚊种群对马拉硫磷 5%和溴氰菊酯 0.25%（5XDC）敏感，但对滴滴涕、标准浓度的溴氰菊酯以及丁醚脲的标准和强度浓度均具有抗药性。在实验室锥形生物测定试验中，致倦库蚊在不同表面接触 Actellic®300CS 和 Icon®10CS 时的死亡率始终保持在 80%以上。在整个 300 天的喷洒后期间，Actellic®300CS 在所有基质上的死亡率均超过 80%。相反，Icon®10CS 在灰泥和木材表面的死亡率在喷洒后 165 天仍保持在 80%以上，在泥土和水泥表面的死亡率在喷洒后 270 天仍保持在 80%以上。在整个 300 天的喷洒后期间，Actellic®300CS 和 Icon®10CS 在所有表面上的每个测试中均在 72 小时内达到 100%的死亡率。
本研究表明，致倦库蚊阿巴斯港种群对不同杀虫剂的抗药性存在差异，并证明了 Actellic®300CS 在控制这些蚊子方面在各种表面上的持续性能。研究结果表明，与目前的选择相比，长效 CS 制剂可能更有效地控制疟疾媒介。需要进一步的研究来验证这些发现，并评估这些杀虫剂对疟疾传播的影响。
