U.S. President's Malaria Initiative VectorLink Project, Washington, DC, USA.
Swiss Center of Scientific Research in Côte d'Ivoire, Abidjan, Côte d'Ivoire.
Sci Rep. 2023 Jul 13;13(1):11364. doi: 10.1038/s41598-023-38583-y.
From August 2020 to June 2021, we assessed the efficacy of SumiShield 50WG (clothianidin), Fludora Fusion 56.25WP-SB (mixture of clothianidin and deltamethrin) and Actellic 300CS (pirimiphos-methyl) in experimental huts when partially sprayed against wild, free-flying populations of Anopheles gambiae s.l. in Tiassalé, Côte d'Ivoire. A one-month baseline period of mosquito collections was conducted to determine mosquito density and resting behavior in unsprayed huts, after which two treatments of partial indoor residual spraying (IRS) were tested: spraying only the top half of walls + ceilings or only the bottom half of walls + ceilings. These were compared to fully sprayed applications using the three IRS insecticide formulations, during twenty nights per month of collection for nine consecutive months. Mortality was assessed at the time of collection, and after a 24 h holding period (Actellic) or up to 120 h (SumiShield and Fludora Fusion). Unsprayed huts were used as a negative control. The efficacy of each partially sprayed treatment of each insecticide was compared monthly to the fully sprayed huts over the study period with a non-inferiority margin set at 10%. The residual efficacy of each insecticide sprayed was also monitored. A total of 2197 Anopheles gambiae s.l. were collected during the baseline and 17,835 during the 9-month period after spraying. During baseline, 42.6% were collected on the bottom half versus 24.3% collected on the top half of the walls, and 33.1% on the ceilings. Over the nine-month post treatment period, 73.5% were collected on the bottom half of the wall, 11.6% collected on the top half and 14.8% on the ceilings. For Actellic, the mean mortality over the nine-month period was 88.5% [87.7, 89.3] for fully sprayed huts, 88.3% [85.1, 91.4] for bottom half + ceiling sprayed walls and 80.8% [74.5, 87.1] for the top half + ceiling sprayed huts. For Fludora Fusion an overall mean mortality of 85.6% [81.5, 89.7] was recorded for fully sprayed huts, 83.7% [82.9, 84.5] for bottom half + ceiling sprayed huts and 81.3% [79.6, 83.0] for the top half + ceiling sprayed huts. For SumiShield, the overall mean mortality was 86.7% [85.3, 88.1] for fully sprayed huts, 85.6% [85.4, 85.8] for the bottom half + ceiling sprayed huts and 76.9% [76.6, 77.3] for the top half + ceiling sprayed huts. For Fludora Fusion, both iterations of partial IRS were non-inferior to full spraying. However, for SumiShield and Actellic, this was true only for the huts with the bottom half + ceiling, reflecting the resting site preference of the local vectors. The results of this study suggest that partial spraying may be a way to reduce the cost of IRS without substantially compromising IRS efficacy.
从 2020 年 8 月到 2021 年 6 月，我们评估了 SumiShield 50WG（噻虫嗪）、Fludora Fusion 56.25WP-SB（噻虫嗪和氯菊酯的混合物）和 Actellic 300CS（吡虫啉）在科特迪瓦蒂亚萨莱的野外、自由飞行的冈比亚按蚊种群中的功效，当它们在实验性小屋中部分喷洒时。在进行为期一个月的蚊子收集基线期之前，先确定未喷洒小屋中的蚊子密度和休息行为，然后测试两次部分室内滞留喷洒（IRS）处理：仅喷洒墙壁和天花板的上半部分或仅喷洒墙壁和天花板的下半部分。这与使用三种 IRS 杀虫剂制剂进行的完全喷洒应用进行了比较，每月收集 20 晚，连续 9 个月。在收集时评估死亡率，并在 24 小时（Actellic）或长达 120 小时（SumiShield 和 Fludora Fusion）后进行评估。未喷洒的小屋用作阴性对照。在研究期间，每月将每种部分喷洒的杀虫剂的疗效与完全喷洒的小屋进行比较，并设定非劣效性边界为 10%。还监测了每种喷洒杀虫剂的残留功效。在基线期和喷洒后 9 个月期间共收集了 2197 只冈比亚按蚊。在基线期，有 42.6%在墙壁的下半部分收集，24.3%在墙壁的上半部分收集，33.1%在天花板上收集。在 9 个月的治疗后期间，有 73.5%在墙壁的下半部分收集，11.6%在墙壁的上半部分收集，14.8%在天花板上收集。对于 Actellic，在 9 个月的期间内，完全喷洒的小屋的平均死亡率为 88.5%[87.7, 89.3]，下半部分+天花板喷洒的墙壁的死亡率为 88.3%[85.1, 91.4]，上半部分+天花板喷洒的小屋的死亡率为 80.8%[74.5, 87.1]。对于 Fludora Fusion，完全喷洒的小屋的总体平均死亡率为 85.6%[81.5, 89.7]，下半部分+天花板喷洒的小屋的死亡率为 83.7%[82.9, 84.5]，上半部分+天花板喷洒的小屋的死亡率为 81.3%[79.6, 83.0]。对于 SumiShield，完全喷洒的小屋的总体平均死亡率为 86.7%[85.3, 88.1]，下半部分+天花板喷洒的小屋的死亡率为 85.6%[85.4, 85.8]，上半部分+天花板喷洒的小屋的死亡率为 76.9%[76.6, 77.3]。对于 Fludora Fusion，两种部分 IRS 迭代均不劣于完全喷洒。然而，对于 SumiShield 和 Actellic，只有下半部分+天花板的小屋如此，这反映了当地蚊子的休息场所偏好。这项研究的结果表明，部分喷洒可能是降低 IRS 成本而不大大降低 IRS 功效的一种方法。
