Sudoi Raymond Kiprop, Esch Keith, Yamba Frederick, Iyikirenga Laurent, Youssef Charlene, Nallo Prince, Swamidoss Isabel, Mapp Carla, Marke Dennis, Smith Samuel Juana, Carshon-Marsh Ronald, Sillah-Kanu Musa, Schnabel Dave, Raharinjatovo Jacky, Carlson Jenny, Levine Rebecca, Alyko Evelyne, Jose Ramlat, Hughes Tony, Jacob Djenam, Yihdego Yemane, Opondo Kevin, Poyer Stephen
PMI VectorLink Project, Population Services International, Nairobi, Kenya.
PMI VectorLink Project, Population Services International, Washington, D.C., USA.
Malar J. 2025 Jul 13;24(1):230. doi: 10.1186/s12936-025-05421-7.
The performance of two piperonyl butoxide (PBO-synergist) insecticide-treated net (ITN) brands, PermaNet 3.0 and Olyset Plus, were evaluated under field conditions in two neighboring districts in Sierra Leone over 36 months to estimate median ITN survival, understand insecticidal efficacy, and identify factors influencing ITN durability. This assessment can help guide future PBO-synergist ITN procurement and replacement strategies.
This prospective study tracked 370 households and 652 campaign-distributed ITNs from 2020, followed annually for 36 months. Districts were purposefully selected based on shared characteristics. Household surveys were conducted, and 30 ITNs per round were tested for bioefficacy and chemical residue. Key indicators included ITN survival, 24-h mosquito mortality, and chemical content reduction compared to manufacturer targets doses. Cox proportional hazard models identified factors influencing ITN survival.
Median useful life was 3.0 (95% CI 2.7-3.5) years for PermaNet 3.0 ITNs in Bo and 2.2 (95% CI 2.0-2.4) years for Olyset Plus ITNs in Moyamba. PermaNet 3.0 ITNs displayed 13% 24-h mortality against pyrethroid-resistant mosquitoes on roof panels, with a 46% reduction in PBO content 34 months post-distribution. Olyset Plus ITNs had 3% f24-hour mortality against pyrethroid-resistant mosquitoes, with a 77% reduction in PBO content. Several factors were associated with improved ITN survival, including cohort ITNs from Bo (adjusted hazard ratio [aHR] = 0.33, p < 0.001), households without children under five (CU5) (aHR = 0.64, p = 0.003), highest socio-economic status tertile (aHR = 0.63, p = 0.016), exposure to social and behaviour change (SBC) messages combined with positive net attitudes (aHR = 0.63, p = 0.008), lack of food storage in sleeping spaces (aHR = 0.56, p = 0.006), exclusive adult use of ITNs (aHR = 0.72, p = 0.048), net folding when not in use (aHR = 0.67, p = 0.015), and drying nets outside (aHR = 0.44, p = 0.008).
ITNs in Bo outperformed those in Moyamba in both physical and insecticidal performance. However, ITN survival is highly context specific, and further investigation into field performance of new ITN types is necessary across diverse epidemiological settings.
在塞拉利昂两个相邻地区的实地条件下，对两种胡椒基丁醚（PBO增效剂）杀虫剂处理蚊帐（ITN）品牌PermaNet 3.0和Olyset Plus进行了36个月的评估，以估计ITN的中位使用寿命，了解杀虫效果，并确定影响ITN耐用性的因素。该评估有助于指导未来PBO增效剂ITN的采购和更换策略。
这项前瞻性研究追踪了2020年的370户家庭和652顶通过活动分发的ITN，每年跟踪一次，为期36个月。根据共同特征有目的地选择地区。进行了家庭调查，每轮测试30顶ITN的生物功效和化学残留。关键指标包括ITN的使用寿命、24小时蚊虫死亡率以及与制造商目标剂量相比的化学含量降低情况。Cox比例风险模型确定了影响ITN使用寿命的因素。
在博城，PermaNet 3.0 ITN的中位使用寿命为3.0（95%可信区间2.7 - 3.5）年；在莫扬巴，Olyset Plus ITN的中位使用寿命为2.2（95%可信区间2.0 - 2.4）年。PermaNet 3.0 ITN在屋顶板上对拟除虫菊酯抗性蚊子的24小时死亡率为13%，分发34个月后PBO含量降低了46%。Olyset Plus ITN对拟除虫菊酯抗性蚊子的24小时死亡率为3%，PBO含量降低了77%。几个因素与ITN使用寿命的延长有关，包括来自博城的队列ITN（调整后风险比[aHR]=0.33，p<0.001）、没有五岁以下儿童（CU5）的家庭（aHR=0.64，p=0.003）、社会经济地位最高三分位数（aHR=0.63，p=0.016）、接触社会和行为改变（SBC）信息并伴有对蚊帐的积极态度（aHR=0.63，p=0.008）、睡眠空间没有食物储存（aHR=0.56，p=0.006）、仅成人使用ITN（aHR=0.72，p=0.048）、不使用时折叠蚊帐（aHR=0.67，p=0.015）以及在室外晾晒蚊帐（aHR=0.44，p=0.008）。
博城的ITN在物理性能和杀虫性能方面均优于莫扬巴的ITN。然而，ITN的使用寿命高度依赖具体环境，有必要在不同的流行病学环境中进一步研究新型ITN的实地性能。
