The effect of repeated washing of long-lasting insecticide-treated nets (LLINs) on the feeding success and survival rates of Anopheles gambiae
The effect of repeated washing of long-lasting insecticide-treated nets (LLINs) on the feeding success and survival rates of Anopheles gambiae
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DOI：
10.1186/1475-2875-9-304
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发表时间：
2010-10-29
期刊：
影响因子：
3
通讯作者：
Vulule, John M.
中科院分区：
文献类型：
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作者：
Atieli, Francis K.;Munga, Stephen O.;Vulule, John M.
背景：经过杀虫剂处理的蚊帐可以保护使用者免受蚊虫叮咬，从而防止蚊媒病原体的传播。反复清洗蚊帐会去除蚊帐上的杀虫剂，使其在短时间内失效。经杀虫剂处理的长效蚊帐 (LLIN) 可以更长时间地防止此类叮咬，因为它们更耐清洗，并且比传统处理的蚊帐更受欢迎。然而，关于LLINs重复清洗对野生疟疾病媒的摄食成功率和存活率影响的信息有限。 方法：本研究评估了四种品牌的LLINs重复清洗对野生株饲养的冈比亚按蚊摄食成功率和存活率的影响。在这项研究中，从 LLIN 覆盖率高的地区收集的怀孕蚊子饲养的 2 至 5 天大的 F1 通过上述 LLIN 的保护屏障提供血粉。蚊子每次暴露时间为10分钟。蚊帐在未清洗的情况下进行测试，随后每 5 次进行测试，直至清洗 15 次。暴露后，根据蚊子的摄食状态对其进行分类。然后将它们在正常实验室条件下放置 24 小时，并对喂食和未喂食的死亡率进行评分。 结果：观察到蚊子不会通过未清洗的 LLIN 屏障进食。然而，喂养成功率和存活率随着连续洗涤次数的增加而增加，并且也与品牌无关。 15 次洗涤后，49% 的载体成功通过 PermaNet 2.0 的保护屏障进食，50% 的载体在 24 小时后死亡，而在相同次数的洗涤后，60% 的载体成功通过 Olyset 品牌的 LLIN 进食，并且全部存活。总体而言，与接受评估的其他四个品牌相比，通过 Olyset 喂食后存活下来的蚊子数量更多。当通过 t 检验分析将单个 LLIN 的功效与传统处理的网进行比较时，Olyset (p = 0.239) 和 NetProtect (TNT) (p = 0.135) 的结果在统计学上没有显着差异。然而，与 PermaNet 和 Interceptor (BASF) 进行比较时，结果非常显着； p值分别为0.015和0.025。结论：本研究结果表明，使用局部清洗方法以短时间间隔重复清洗LLIN可以在短时间内使其具有感染性，从而防止局部媒介进食。
Background: Insecticide-treated nets protect users from mosquito bites, thereby preventing transmissions of mosquito borne pathogens. Repeated washing of nets removes insecticide on the netting rendering them ineffective within a short period. Long-lasting insecticide-treated nets (LLINs) offer longer time protection against such bites because they are more wash resistant, and are preferred to conventionally treated nets. However, there is limited information on the effect of repeated washing of LLINs on the feeding success and survival of wild malaria vectors.Methods: The current study evaluated the effect of repeated washing of four brands of LLINs on the feeding success and survival rates of Anopheles gambiae sl reared from wild strains. In this study, two-to five-day old F1s, reared from gravid mosquitoes collected from an area with a high coverage of LLINs were offered blood meals through protective barriers of the above LLINs. Mosquitoes were exposed for a period of 10 minutes each time. Nets were tested unwashed and subsequently after every 5(th) through wash 15. After exposure mosquitoes were sorted out according to their feeding status. They were then held under normal laboratory conditions for 24 hours and mortality was scored in both fed and unfed.Results: It was observed that mosquitoes did not feed through a barrier of unwashed LLINs. However, the feeding success and survival rates increased with successive number of washes and were also net brand dependant. After 15 washes, 49% of vectors succeeded to feed through a protective barrier of PermaNet 2.0 and 50% of the fed died after 24 hrs while after the same number of washes 60% of vectors succeeded to feed through Olyset brand of LLINs and all of them survived. In general, more mosquitoes survived after feeding through Olyset compared to the other four brands that were evaluated. When efficacy of individual LLINs was compared by a t-test analysis to a conventionally treated net, the results were not significantly different statistically for Olyset (p = 0.239) and NetProtect (TNT) (p = 0.135). However, the results were highly significant when comparison was made with PermaNet and Interceptor (BASF); p values 0.015 and 0.025 respectively.Conclusion: The result of this study shows that repeated washing of LLINs at short time intervals using local washing methods may render them infective within a short time in preventing local vectors from feeding.