PMI VectorLink Project, Population Services International, Antananarivo, Madagascar.
Institut de Recherche en Sciences de La Santé, Bobo-Dioulasso, Burkina Faso.
Malar J. 2024 Jun 4;23(1):173. doi: 10.1186/s12936-024-04989-w.
National Malaria Programmes (NMPs) monitor the durability of insecticide-treated nets (ITNs) to inform procurement and replacement decisions. This is crucial for new dual active ingredients (AI) ITNs, for which less data is available. Pyrethroid-only ITN (Interceptor) and dual AI (Interceptor® G2, and PermaNet 3.0) ITNs were assessed across three health districts over 36 months in southern Burkina Faso to estimate median ITN survival, insecticidal efficacy, and to identify factors contributing to field ITN longevity.
Durability was monitored through a prospective study of a cohort of nets distributed during the 2019 mass campaign. Three health districts were selected for their similar pyrethroid-resistance, environmental, epidemiological, and population profiles. Households were recruited after the mass campaign, with annual household questionnaire follow-ups over three years. Each round, ITNs were withdrawn for bioassays and chemical residue testing. Key measures were the percentage of cohort ITNs in serviceable condition, insecticidal effectiveness, and chemical residue content against target dose. Cox proportional hazard models were used to identify determinants influencing ITN survival.
At endline, the median useful life was 3.2 (95% CI 2.5-4.0) years for PermaNet 3.0 ITNs in Orodara, 2.6 (95% CI 1.9-3.2) years for Interceptor® G2 ITNs in Banfora and 2.4 (95% CI 1.9-2.9) years for Interceptor® ITNs in Gaoua. Factors associated with ITN survival included cohort ITNs from Orodara (adjusted hazard ratio (aHR) = 0.58, p = 0.026), households seeing less rodents (aHR = 0.66, p = 0.005), female-headed households (aHR = 0.66, p = 0.044), exposure to social behavior change (SBC) messages (aHR = 0.52, ≤ 0.001) and folding nets when not in use (aHR = 0.47, p < 0.001). At endline, PermaNet® 3.0 ITN recorded 24-h mortality of 26% against resistant mosquitos on roof panels, with an 84% reduction in PBO content. Interceptor G2 ITN 72-h mortality was 51%, with a 67% reduction in chlorfenapyr content. Interceptor ITN 24-h mortality was 71%, with an 84% reduction in alpha-cypermethrin content.
Only PermaNet 3.0 ITNs surpassed the standard three-year survival threshold. Identified protective factors should inform SBC messaging. Significant decreases in chemical content and resulting impact on bioefficacy warrant more research in other countries to better understand dual AI ITN insecticidal performance.
国家疟疾规划（NMP）监测杀虫剂处理蚊帐（ITN）的耐久性，为采购和更换决策提供信息。对于新的双活性成分（AI）ITN 来说，这一点至关重要，因为这种 ITN 的可用数据较少。在布基纳法索南部的三个卫生区，对拟除虫菊酯-only ITN（Interceptor）和双 AI（Interceptor® G2 和 PermaNet 3.0）ITN 进行了 36 个月的评估，以估计 ITN 的中位存活时间、杀虫功效，并确定导致现场 ITN 寿命延长的因素。
通过对 2019 年大规模运动期间分发的一批蚊帐进行前瞻性研究来监测耐久性。选择了三个卫生区，这些卫生区的拟除虫菊酯耐药性、环境、流行病学和人口状况相似。在大规模运动后招募家庭，并在三年内每年进行家庭问卷调查。每一轮，都会撤回 ITN 进行生物测定和化学残留测试。关键措施是可使用的队列 ITN 百分比、杀虫效果和针对目标剂量的化学残留含量。使用 Cox 比例风险模型确定影响 ITN 存活的决定因素。
在终线时，Orodara 的 PermaNet 3.0 ITN 的中位有用寿命为 3.2（95%CI 2.5-4.0）年，Banfora 的 Interceptor® G2 ITN 为 2.6（95%CI 1.9-3.2）年，Gaoua 的 Interceptor® ITN 为 2.4（95%CI 1.9-2.9）年。与 ITN 存活相关的因素包括来自 Orodara 的队列 ITN（调整后的危险比（aHR）=0.58，p=0.026）、家庭中见到的啮齿动物较少（aHR=0.66，p=0.005）、女性户主家庭（aHR=0.66，p=0.044）、接触社会行为改变（SBC）信息（aHR=0.52，≤0.001）和不用时折叠 ITN（aHR=0.47，p<0.001）。在终线时，PermaNet® 3.0 ITN 在屋顶面板上对抗药性蚊子的 24 小时死亡率为 26%，PBO 含量减少 84%。Interceptor G2 ITN 的 72 小时死亡率为 51%，氯氟醚菊酯含量减少 67%。Interceptor ITN 的 24 小时死亡率为 71%，α-氯氰菊酯含量减少 84%。
只有 PermaNet 3.0 ITN 超过了标准的三年存活阈值。确定的保护因素应告知 SBC 信息。化学物质含量的显著下降及其对生物功效的影响，需要在其他国家进行更多研究，以更好地了解双 AI ITN 的杀虫性能。
