Centre de Recherche Entomologique de Cotonou (CREC), Ministry of Health, Cotonou, Benin.
Faculté des Sciences et Techniques, University of Abomey-Calavi, Abomey-Calavi, Benin.
Malar J. 2020 Feb 4;19(1):58. doi: 10.1186/s12936-020-3138-7.
Long-lasting insecticidal nets (LLINs) are designed to survive and sustain their physical barrier for 3 years in household conditions. However, studies have shown that most of these nets are usually torn or no longer present in the households in less than 3 years. This study was initiated in Benin to compare the survivorship and physical integrity of seven types of LLINs in a same socio-geographic area.
In August 2017, 1890 households were selected in 9 villages in the municipality of Zagnanado in central Benin. Each one of the selected households received one of the seven LLIN products: Aspirational, DawaPlus 2.0, OlysetNet, PermaNet 2.0, PermaNet 3.0, Royal Sentry and Yorkool. Overall, 270 LLINs of each type were freely distributed in Zagnanado, at a rate of 30 LLINs per type per village. These bed nets have been monitored and evaluated every 6 months to identify the most resilient and preferred LLINs in the community. Net survivorship was assessed using the rate of net loss and physical condition.
The survivorship of all types of LLIN was estimated at 92% (95% CI 90.33-92.96) after 6 months and 70% (95% CI 67.25-71.81) after a year of use. At 12 months, all bed nets monitored were below the NetCalc model threshold of 92.8% for an LLIN with a lifespan of 3 years. Only 1.73% of all types of LLIN had a visible loss of integrity after 6 months with a median proportionate hole index (PHI) estimated at zero. The percentage significantly increased after 12 months with 10.41% of damaged nets (all types of LLINs). The median PHI for each brand of net was 23, 196, 141, 23, 23, 121 and 72, respectively for Aspirational, DawaPlus 2.0, OlysetNet, PermaNet 2.0, PermaNet 3.0, Royal Sentry and Yorkool. A significant difference was noted between the PHI at 6 and 12 months (p < 0.0001). After 12 months, the DawaPlus2.0, OlysetNet and Royal Sentry suffered significantly more damage compared to the others (p < 0.001).
The results of this study showed that after a year of use, the survivorship of the 7 LLIN products in households was lower than expected. However, all the LLIN products successfully met WHO standards for physical integrity after 12 months of use. The monitoring continues. The next steps will help to identify the most sustainable LLINs.
长效杀虫蚊帐（LLINs）旨在在家庭环境中存活并维持其物理屏障 3 年。然而，研究表明，这些蚊帐中的大多数通常在不到 3 年内就会在家庭中撕裂或不再存在。本研究在贝宁发起，旨在比较同一社会地理区域内七种类型的 LLIN 的生存能力和物理完整性。
2017 年 8 月，在贝宁中部扎加纳多市的 9 个村庄中选择了 1890 户家庭。每个选定的家庭都收到了七种 LLIN 产品之一：Aspirational、DawaPlus 2.0、OlysetNet、PermaNet 2.0、PermaNet 3.0、Royal Sentry 和 Yorkool。总共在扎加纳多自由分发了每种类型的 270 个蚊帐，每个村庄 30 个。这些蚊帐每 6 个月监测和评估一次，以确定社区中最具弹性和首选的 LLIN。使用失效率和物理状况评估蚊帐的生存能力。
使用 6 个月后，所有类型的 LLIN 的生存率估计为 92%（95%CI 90.33-92.96），使用 1 年后为 70%（95%CI 67.25-71.81）。使用 12 个月后，所有监测到的蚊帐均低于 NetCalc 模型 3 年寿命 LLIN 的 92.8%阈值。使用 6 个月后，只有 1.73%的所有类型的 LLIN 出现明显的完整性损失，中位数比例孔指数（PHI）估计为零。12 个月后，受损蚊帐的百分比显著增加，达到 10.41%（所有类型的 LLIN）。每个品牌的蚊帐的中位数 PHI 分别为 Aspirational 为 23、DawaPlus 2.0 为 196、OlysetNet 为 141、PermaNet 2.0 为 23、PermaNet 3.0 为 23、Royal Sentry 为 121 和 Yorkool 为 72。使用 6 个月和 12 个月时 PHI 之间存在显著差异（p<0.0001）。使用 12 个月后，与其他品牌相比，DawaPlus2.0、OlysetNet 和 Royal Sentry 遭受的损坏明显更多（p<0.001）。
这项研究的结果表明，在使用一年后，家庭中 7 种 LLIN 产品的生存率低于预期。然而，所有 LLIN 产品在使用 12 个月后均成功符合世卫组织对物理完整性的标准。监测仍在继续。下一步将有助于确定最可持续的 LLIN。
