London School of Hygiene and Tropical Medicine (LSHTM), London, UK.
Centre de Recherches Entomologiques de Cotonou (CREC), Cotonou, Benin.
Malar J. 2022 Jan 11;21(1):20. doi: 10.1186/s12936-022-04041-9.
Pyrethroid-PBO nets were conditionally recommended for control of malaria transmitted by mosquitoes with oxidase-based pyrethroid-resistance based on epidemiological evidence of additional protective effect with Olyset Plus compared to a pyrethroid-only net (Olyset Net). Entomological studies can be used to assess the comparative performance of other brands of pyrethroid-PBO ITNs to Olyset Plus.
An experimental hut trial was performed in Cové, Benin to compare PermaNet 3.0 (deltamethrin plus PBO on roof panel only) to Olyset Plus (permethrin plus PBO on all panels) against wild pyrethroid-resistant Anopheles gambiae sensu lato (s.l.) following World Health Organization (WHO) guidelines. Both nets were tested unwashed and after 20 standardized washes compared to Olyset Net. Laboratory bioassays were also performed to help explain findings in the experimental huts.
With unwashed nets, mosquito mortality was higher in huts with PermaNet 3.0 compared to Olyset Plus (41% vs. 28%, P < 0.001). After 20 washes, mortality declined significantly with PermaNet 3.0 (41% unwashed vs. 17% after washing P < 0.001), but not with Olyset Plus (28% unwashed vs. 24% after washing P = 0.433); Olyset Plus induced significantly higher mortality than PermaNet 3.0 and Olyset Net after 20 washes. PermaNet 3.0 showed a higher wash retention of PBO compared to Olyset Plus. A non-inferiority analysis performed with data from unwashed and washed nets together using a margin recommended by the WHO, showed that PermaNet 3.0 was non-inferior to Olyset Plus in terms of mosquito mortality (25% with Olyset Plus vs. 27% with PermaNet 3.0, OR = 1.528, 95%CI = 1.02-2.29) but not in reducing mosquito feeding (25% with Olyset Plus vs. 30% with PermaNet 3.0, OR = 1.192, 95%CI = 0.77-1.84). Both pyrethroid-PBO nets were superior to Olyset Net.
Olyset Plus outperformed PermaNet 3.0 in terms of its ability to cause greater margins of improved mosquito mortality compared to a standard pyrethroid net, after multiple standardized washes. However, using a margin of non-inferiority defined by the WHO, PermaNet 3.0 was non-inferior to Olyset Plus in inducing mosquito mortality. Considering the low levels of mortality observed and increasing pyrethroid-resistance in West Africa, it is unclear whether either of these nets would demonstrate the same epidemiological impact observed in community trials in East Africa.
基于流行病学证据表明，与仅含除虫菊酯的 Olyset 网相比，添加了增效醚的拟除虫菊酯 -PBO 蚊帐对氧化酶基拟除虫菊酯抗性的蚊子具有额外的保护作用，因此有条件推荐使用含增效醚的拟除虫菊酯 -PBO 蚊帐来控制由蚊子传播的疟疾。昆虫学研究可用于评估其他品牌的含拟除虫菊酯 -PBO ITN 与 Olyset Plus 相比的相对性能。
在贝宁的 Cové 进行了一项实验性小屋试验，根据世界卫生组织（WHO）的指南，比较了 PermaNet 3.0（屋顶面板上只有氯菊酯和增效醚）与 Olyset Plus（所有面板上都有氯菊酯和增效醚）对野生的具有拟除虫菊酯抗性的冈比亚按蚊（s.l.）的效果。两种蚊帐在未经洗涤和经过 20 次标准化洗涤后分别与 Olyset Net 进行了比较。还进行了实验室生物测定，以帮助解释实验性小屋中的发现。
未经洗涤的蚊帐中，PermaNet 3.0 引起的蚊虫死亡率高于 Olyset Plus（41%比 28%，P<0.001）。经过 20 次洗涤后，PermaNet 3.0 的死亡率显著下降（41%未经洗涤与洗涤后 17%，P<0.001），而 Olyset Plus 则没有（28%未经洗涤与洗涤后 24%，P=0.433）；经过 20 次洗涤后，Olyset Plus 引起的死亡率明显高于 PermaNet 3.0 和 Olyset Net。PermaNet 3.0 显示出比 Olyset Plus 更高的增效醚洗涤保留率。使用世卫组织推荐的边际进行未经洗涤和洗涤网数据的非劣效性分析表明，PermaNet 3.0 在蚊虫死亡率方面不劣于 Olyset Plus（Olyset Plus 为 25%，PermaNet 3.0 为 27%，OR=1.528，95%CI=1.02-2.29），但在减少蚊虫叮咬方面不如 Olyset Plus（Olyset Plus 为 25%，PermaNet 3.0 为 30%，OR=1.192，95%CI=0.77-1.84）。两种含拟除虫菊酯 -PBO 蚊帐均优于 Olyset Net。
经过多次标准化洗涤后，与标准的除虫菊酯网相比，Olyset Plus 能更有效地提高蚊虫死亡率，从而产生更大的效果边际。然而，使用世卫组织定义的非劣效性边际，PermaNet 3.0 在诱导蚊虫死亡率方面并不劣于 Olyset Plus。考虑到观察到的死亡率较低和西非拟除虫菊酯抗性的增加，尚不清楚这两种蚊帐是否会在东非的社区试验中表现出相同的流行病学影响。
