Malima Robert C, Magesa Stephen M, Tungu Patrick K, Mwingira Victor, Magogo Frank S, Sudi Wema, Mosha Frank W, Curtis Christopher F, Maxwell Caroline, Rowland Mark
London School of Hygiene and Tropical Medicine, WC1E 7HT, London, UK.
Malar J. 2008 Feb 28;7:38. doi: 10.1186/1475-2875-7-38.
Long-lasting insecticidal nets (LLINs) are advocated by WHO for protection against malaria. Of the three brands of LLINs currently approved by WHO, Olyset(R) is the only one currently granted full recommendation. With this type of LLIN, the insecticide (permethrin) is incorporated into the polyethylene fibre during manufacture and diffuses from the core to the surface, thereby maintaining surface concentrations. It has not been determined for how long Olyset nets remain protective against mosquitoes in household use.
Examples of Olyset nets, which had been in use in Tanzanian villages for seven years, were tested in experimental huts against naturally entering Anopheles gambiae and Anopheles funestus mosquitoes. Performance was compared with new Olyset nets, conventionally treated ITNs (either newly treated with alphacypermethrin or taken from local villages after 1.5 years of use) and untreated nets. All nets were artificially holed except for the seven-year Olyset nets, which had developed holes during prolonged domestic use.
Anopheles funestus and An. gambiae in NE Tanzania are susceptible to pyrethroids. The new Olyset nets caused high mortality against An. funestus (73.9%) and An. gambiae (62.7%) in experimental huts. The seven-year Olyset nets caused 58.9% mortality against An. funestus and 40.0% mortality against An. gambiae. The freshly treated alphacypermethrin nets also caused high mortality against An. funestus (70.6%) and An. gambiae (72.0%); this decreased to 58.4% and 69.6% respectively after 1.5 years of use. The new Olyset nets inhibited blood-feeding by 40-50%. The 7 year Olyset nets showed no feeding inhibition over that shown by the untreated nets. The alphacypermethrin treated nets failed to inhibit blood-feeding after 1.5 years of use. However iHhhdn laboratory tunnel tests samples of all types of treated net including the 7 year Olyset inhibited blood-feeding by more than 95%.
After seven years of use Olyset nets were still strongly insecticidal. Mosquito mortality decreased by only 20-35% over this period. However, Olyset would not provide personal protection after seven years unless it was in good condition and all holes fully repaired.
世界卫生组织提倡使用长效驱虫蚊帐（LLINs）来预防疟疾。在世界卫生组织目前批准的三种长效驱虫蚊帐品牌中，Olyset®是目前唯一获得全面推荐的品牌。对于这种长效驱虫蚊帐，杀虫剂（氯菊酯）在制造过程中被融入聚乙烯纤维，并从芯部扩散到表面，从而维持表面浓度。尚未确定Olyset蚊帐在家庭使用中对蚊子的防护能持续多长时间。
在坦桑尼亚村庄使用了七年的Olyset蚊帐样本，在实验小屋中针对自然进入的冈比亚按蚊和嗜人按蚊进行了测试。将其性能与新的Olyset蚊帐、常规处理的经杀虫剂处理的蚊帐（要么用高效氯氰菊酯新处理，要么在使用1.5年后从当地村庄获取）以及未处理的蚊帐进行比较。除了使用了七年的Olyset蚊帐在长期家庭使用中已出现破洞外，所有蚊帐都人为制造了破洞。
坦桑尼亚东北部的嗜人按蚊和冈比亚按蚊对拟除虫菊酯敏感。新的Olyset蚊帐在实验小屋中对嗜人按蚊（73.9%）和冈比亚按蚊（62.7%）造成了高死亡率。使用了七年的Olyset蚊帐对嗜人按蚊造成了58.9%的死亡率，对冈比亚按蚊造成了40.0%的死亡率。新处理的高效氯氰菊酯蚊帐对嗜人按蚊（70.6%）和冈比亚按蚊（72.0%）也造成了高死亡率；使用1.5年后，这一比例分别降至58.4%和69.6%。新的Olyset蚊帐抑制吸血率为40 - 50%。使用了七年的Olyset蚊帐与未处理的蚊帐相比，未显示出吸血抑制作用。使用1.5年后，高效氯氰菊酯处理的蚊帐未能抑制吸血。然而，在实验室风洞试验中，包括使用了七年的Olyset蚊帐在内的所有类型的处理蚊帐样本抑制吸血率均超过95%。
使用七年的Olyset蚊帐仍具有很强的杀虫效果。在此期间，蚊子死亡率仅下降了20 - 35%。然而，使用七年的Olyset蚊帐除非状况良好且所有破洞都完全修复，否则无法提供个人防护。
