Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya.
Malar J. 2010 Aug 30;9:248. doi: 10.1186/1475-2875-9-248.
The current study was undertaken to determine the optimal wash-drying regimen and the effects of different washing procedures on the efficacy, and durability of four brands of newly introduced long-lasting insecticide-treated nets (LLINs) under tropical conditions.
In the current study, the following four LLINs were tested: Olyset, PermaNet 2.0, BASF and TNT. Nets were divided into three sets; one set was washed by hand rubbing and air-dried either hanging or spread on the ground in direct sunlight or hanging or spread on the ground under the shade. A second set was washed using the WHO protocol (machine) and the third set was washed by beating the nets on rocks. The biological activities of the nets were assessed by a three-minute bioassay cone test and the residual insecticide contents were determined using high performance liquid chromatography (HPLC) procedure.
Nets that were dried hanging under the shade retained more insecticide, 62.5% and recorded higher mortality compared to nets which were dried lying on the ground in direct sunlight 58.8%, nets dried under the shade spread on the ground 56.3%, and 57.8% for nets dried hanging in direct sunlight. It was also observed that nets washed by the standard WHO protocol, retained more insecticide and were more effective in killing mosquitoes compared to nets washed by local methods of hand rubbing and beating on rocks. There were significant differences between drying regimens (p < 0.0001) and between washing procedures (p < 0.001) respectively. However, the effect of net type was statistically insignificant. The statistical differences on individual nets were also compared, for PermaNet and TNT there were no significant differences observed between the four drying regimens (p = 0.7944 and 0.4703) respectively). For BASF and Olyset, the differences were significant (p < 0.001 and p > 0.0001).
The results of this study suggest that washing and drying regimen influence the insecticidal activity of LLINs. The standard WHOPES washing protocol underestimates the amount of insecticide washed from LLINs compared to the abrasive washing procedures that are used in the field. This suggests that there is need to educate net users to adopt a more gentle washing procedure while handling LLINs. The education should accompany net distribution campaigns.
本研究旨在确定最佳洗涤-干燥方案，并评估不同洗涤程序对四种新引入的长效驱虫蚊帐（LLINs）在热带条件下的功效和耐久性的影响。
在本研究中，对以下四种 LLIN 进行了测试：Olyset、PermaNet 2.0、BASF 和 TNT。将蚊帐分为三组；一组通过手搓和风干进行洗涤，要么悬挂晾干，要么在阳光下铺在地上晾干，要么在阴凉处铺在地上晾干。第二组按照世界卫生组织（WHO）的方案（机洗）进行洗涤，第三组通过在岩石上拍打蚊帐进行洗涤。通过三分钟生物测定锥形试验评估蚊帐的生物活性，并使用高效液相色谱（HPLC）程序测定残留杀虫剂含量。
在阴凉处悬挂晾干的蚊帐保留了更多的杀虫剂，为 62.5%，死亡率也更高，为 58.8%，比在阳光下直接铺在地上晾干的蚊帐（58.8%）、在阴凉处铺在地上晾干的蚊帐（56.3%）和在阳光下悬挂晾干的蚊帐（57.8%）更高。研究还观察到，按照标准 WHO 方案洗涤的蚊帐保留了更多的杀虫剂，并且在杀死蚊子方面比按照当地手搓和拍打岩石的方法洗涤的蚊帐更有效。干燥方案之间（p < 0.0001）和洗涤程序之间（p < 0.001）分别存在显著差异。然而，蚊帐类型的影响在统计学上并不显著。还比较了个体蚊帐的统计差异，对于 PermaNet 和 TNT，在四种干燥方案之间没有观察到显著差异（p = 0.7944 和 0.4703）。对于 BASF 和 Olyset，差异显著（p < 0.001 和 p > 0.0001）。
本研究结果表明，洗涤和干燥方案会影响 LLINs 的杀虫活性。与现场使用的研磨洗涤程序相比，世界卫生组织标准洗涤方案低估了从 LLINs 中洗去的杀虫剂的量。这表明，在处理 LLINs 时，需要教育蚊帐使用者采用更温和的洗涤程序。该教育应伴随蚊帐分发运动。
