The bioefficacy of a novel VECTRON™ T500 indoor residual spray formulation in an experimental huts trial against Anopheles gambiae s.l. populations

IF 2.1 3区 医学 Q2 PARASITOLOGY
Eliningaya J. Kweka , Lucile Lyaruu , Adrian S. Massawe , Ibrahim H. Sungi , Aneth M. Mahande
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引用次数: 0

Abstract

Background: The emergence of insecticide resistance and its spread through populations of malaria vectors has decreased the number of insecticides available for control. Insecticide resistance has been observed in vector populations across sub-Saharan Africa in malaria endemic areas. Therefore, new compounds with different modes of action are needed that can be used in the management of resistance. The current study assessed the bioefficacy of the new indoor residual spray formulation, VECTRON™ T500 against Klypson 500 WG and water against laboratory reared and wild populations of Anopheles gambiae s.l.. The comparative experimental hut trial was implemented between June 2022 and December 2022 to determine the efficacy of VECTRON™ T500, containing the active ingredient (ai) broflanilide as a 50 % wettable powder (WP). The efficacy of VECTRON™ T500 was compared with a positive control, Klypson 500 WG, a wettable granule (WG) formulation that contains 50 % clothianidin. Cement and mud walls were sprayed with VECTRON™ T500, Klypson 500 WG with water sprayed as a negative control. The two insecticides and negative control were evaluated monthly for six months against laboratory and the field-derived An. gambiae s.l. using the standard WHO cone bioassays. Each wall had two cones on each day of testing. VECTRON™ T500 was sprayed on both surface types at a rate of 100mg ai/m2 whilst Klypson 500 WG was applied at a rate of 300 mg ai/m2. For both wall surface types, the vector from the laboratory-reared and the wild populations exhibited a low knockdown effect to both VECTRON™ T500 and Klypson 500 WG. A total of 3,840 mosquitoes were used of which 2,880 (75 %) were susceptible colony of An. gambiae s.s. and 960 (25 %) were wild An. gambiae s.l.. The VECTRON™ T500 induced a mortality of 97.8 %-98.1 % in the laboratory population and 83.2-95.0 % wild population mosquitoes on cement and mud-walled huts respectively while Klypson 500 WG ranged from 89.6-99.0 % for wild and 99.0-99.3 % for the laboratory population mosquitoes on cement and mud walls respectively. The knockdown due to VECTRON™ T500 was 7.08 % in the sixth month, while for Klypson 500 WG was 16.04-17.50 %. The monthly wall cone bioassay mortality with VECTRON™ T500 remained over 80 % for 6 months post-spraying for both laboratory and wild populations. The findings of this study have shown VECTRON™ T500 to have extended efficacy against malaria vector mosquitoes when applied to cement and mud walls. The evaluated new IRS formulation, VECTRON™ T500, performed equally with the positive control, Klypson 500 WG, regarding its impact on vector mortality.

新型 VECTRON™ T500 室内滞留喷雾制剂在针对冈比亚按蚊种群的实验性小屋试验中的生物功效。
背景:杀虫剂抗药性的出现及其在疟疾病媒种群中的传播减少了可用于控制的杀虫剂数量。在撒哈拉以南非洲疟疾流行地区的病媒种群中发现了杀虫剂抗药性。因此,需要具有不同作用模式的新化合物来控制抗药性。本研究评估了新型室内滞留喷洒制剂 VECTRON™ T500 对 Klypson 500 WG 和水对实验室饲养和野生冈比亚按蚊种群的生物效力。2022 年 6 月至 2022 年 12 月期间进行了小屋比较试验,以确定 VECTRON™ T500 的药效,该产品含有 50%可湿性粉剂(WP)的活性成分(ai)溴氟尼胺。VECTRON™ T500 的药效与阳性对照 Klypson 500 WG 进行了比较,Klypson 500 WG 是一种含有 50% 溴氰菊酯的可湿性颗粒剂 (WG)。水泥墙和泥墙喷洒 VECTRON™ T500,Klypson 500 WG 和水作为阴性对照。采用世界卫生组织标准锥体生物测定法,在六个月内每月对两种杀虫剂和阴性对照进行一次实验室和田间冈比亚蚁评估。每面墙在测试的每一天都有两个锥体。在两种墙面上喷洒 VECTRON™ T500,剂量为 100 毫克活性成分/平方米,而喷洒 Klypson 500 WG,剂量为 300 毫克活性成分/平方米。在两种墙面类型中,实验室饲养和野生种群的病媒对 VECTRON™ T500 和 Klypson 500 WG 的抑制效果都很低。总共使用了 3 840 只蚊子,其中 2 880 只(75%)是冈比亚疟蚊的易感群体,960 只(25%)是野生冈比亚疟蚊。VECTRON™ T500 在水泥墙和泥墙小屋的实验室蚊群死亡率为 97.8%-98.1%,野生蚊群死亡率为 83.2%-95.0%,而 Klypson 500 WG 在水泥墙和泥墙小屋的野生蚊群死亡率为 89.6%-99.0%,实验室蚊群死亡率为 99.0%-99.3%。VECTRON™ T500 在第六个月的击倒率为 7.08%,而 Klypson 500 WG 为 16.04-17.50%。在喷洒 VECTRON™ T500 后的 6 个月内,实验室和野生种群的每月壁锥生物测定死亡率均保持在 80% 以上。这项研究结果表明,VECTRON™ T500 在水泥墙和泥墙上施用时,对疟疾病媒蚊虫具有延长的效力。在对病媒死亡率的影响方面,经评估的新型 IRS 制剂 VECTRON™ T500 与阳性对照 Klypson 500 WG 的效果相当。
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来源期刊
Acta tropica
Acta tropica 医学-寄生虫学
CiteScore
5.40
自引率
11.10%
发文量
383
审稿时长
37 days
期刊介绍: Acta Tropica, is an international journal on infectious diseases that covers public health sciences and biomedical research with particular emphasis on topics relevant to human and animal health in the tropics and the subtropics.
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