Malaria Research and Training Centre, Faculty of Medicine, Pharmacy and Odonto-Stomatology, University of Sciences, Techniques and Technology of Bamako, BP 1805, Bamako, Mali.
Department of Zoology, Tel Aviv University, 61500, Tel Aviv, Israel.
Malar J. 2020 Feb 14;19(1):72. doi: 10.1186/s12936-020-3132-0.
The aim of this field trial was to evaluate the efficacy of attractive toxic sugar baits (ATSB) in Mali, where sustained malaria transmission occurs despite the use of long-lasting insecticidal nets (LLINs). ATSB bait stations were deployed in seven of 14 similar study villages, where LLINs were already in widespread use. The combined use of ATSB and LLINs was tested to see if it would substantially reduce parasite transmission by Anopheles gambiae sensu lato beyond use of LLINs alone.
A 2-day field experiment was conducted to determine the number of mosquitoes feeding on natural sugar versus those feeding on bait stations containing attractive sugar bait without toxin (ASB)-but with food dye. This was done each month in seven random villages from April to December 2016. In the following year, in seven treatment villages from May to December 2017, two ATSB bait stations containing the insecticide dinotefuran were placed on the outer walls of each building. Vector population density was evaluated monthly by CDC UV light traps, malaise traps, pyrethrum spray (PSCs) and human landing catches (HLCs). Female samples of the catch were tested for age by examination of the ovarioles in dissected ovaries and identification of Plasmodium falciparum sporozoite infection by ELISA. Entomological inoculation rates (EIR) were calculated, and reductions between treated and untreated villages were determined.
In the 2-day experiment with ASB each month, there was a lower number of male and female mosquitoes feeding on the natural sugar sources than on the ASB. ATSB deployment reduced CDC-UV trap female catches in September, when catches were highest, were by 57.4% compared to catches in control sites. Similarly, malaise trap catches showed a 44.3% reduction of females in August and PSC catches of females were reduced by 48.7% in September. Reductions of females in HLCs were lower by 19.8% indoors and 26.3% outdoors in September. The high reduction seen in the rainy season was similar for males and reductions in population density for both males and females were > 70% during the dry season. Reductions of females with ≥ 3 gonotrophic cycles were recorded every month amounting to 97.1% in October and 100.0% in December. Reductions in monthly EIRs ranged from 77.76 to 100.00% indoors and 84.95% to 100.00% outdoors. The number of sporozoite infected females from traps was reduced by 97.83% at treated villages compared to controls.
Attractive toxic sugar baits used against Anopheles mosquitoes in Mali drastically reduced the density of mosquitoes, the number of older females, the number of sporozoite infected females and the EIR demonstrating how ATSB significantly reduces malaria parasite transmission.
本现场试验旨在评估诱捕毒饵（ATSB）在马里的功效，马里存在持续的疟疾传播，尽管已经广泛使用长效驱虫蚊帐（LLINs）。在 14 个类似研究村中，有 7 个部署了 ATSB 诱饵站，这些村庄已经广泛使用了 LLINs。试验同时使用 ATSB 和 LLINs，以观察其是否能在单独使用 LLINs 的基础上，显著降低冈比亚按蚊传播的寄生虫数量。
2016 年 4 月至 12 月期间，在 7 个随机村庄进行了为期两天的现场试验，以确定吸食天然糖的蚊子数量和吸食含有诱糖但不含毒素的毒饵（ASB）的蚊子数量（ASB-但含有食物染料）。此后，2017 年 5 月至 12 月，在 7 个治疗村中，每个建筑物的外墙上放置了两个含有杀虫剂敌敌畏的 ATSB 毒饵站。每月通过 CDC 紫外线诱捕器、诱蚊器、拟除虫菊酯喷雾（PSCs）和人体诱蚊器（HLCs）评估蚊群密度。通过检查解剖卵巢中的卵巢管和酶联免疫吸附试验（ELISA）鉴定间日疟原虫孢子虫感染来检测捕获的雌性样本的年龄。计算昆虫接种率（EIR），并确定处理村与未处理村之间的差异。
在每月进行的两天 ASB 试验中，吸食天然糖源的雄性和雌性蚊子数量均少于吸食 ASB 的蚊子数量。ATSB 的部署使 9 月的 CDC-UV 诱捕器雌性捕获量减少了 57.4%，而控制区的捕获量则减少了 57.4%。同样，诱蚊器捕获的雌性数量减少了 44.3%，8 月 PSC 捕获的雌性数量减少了 48.7%。9 月，HLC 中雌性捕获量的降幅分别为室内 19.8%，室外 26.3%。在雨季观察到的高降幅在雄性中也相似，在旱季，雄性和雌性的种群密度降幅均超过 70%。每月都记录到≥3 个生殖周期的雌性减少，10 月减少 97.1%，12 月减少 100.0%。每月室内 EIR 降幅为 77.76%至 100.00%，室外 EIR 降幅为 84.95%至 100.00%。与对照组相比，来自诱蚊器的感染疟原虫的雌性数量减少了 97.83%。
在马里，针对按蚊的诱捕毒饵大大降低了蚊子密度、老年雌性数量、感染疟原虫的雌性数量和 EIR，表明 ATSB 显著降低了疟疾寄生虫的传播。
