Department of Zoological Sciences, Addis Ababa University, PO. Box 1176, Addis Ababa, Ethiopia.
Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, PO. Box 102, Alnarp, Sweden.
Malar J. 2020 Sep 4;19(1):327. doi: 10.1186/s12936-020-03378-3.
Plasmodium parasites manipulate the interaction between their mosquito and human hosts. Patients infected with gametocytes attract anopheline mosquitoes differentially compared to healthy individuals, an effect associated with an increased release of attractive volatile cues. This odour-driven manipulation is partly mediated by the gametocyte-specific metabolite, (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), which induces increased release of select aldehydes and terpenes from red blood cells and results in the enhanced attraction of host-seeking mosquitoes, which are vectors of malaria. This study investigates the effect of the HMBPP-induced volatiles on the attraction of wild Anopheles mosquitoes to humans under field conditions.
The efficacy of the HMBPP-induced odour blend to attract Anopheles was evaluated in a 4 × 6 Latin rectangular study design indoors using baited Suna traps. Furthermore, to assess the efficacy of the HMBPP-induced odour blend in (1) augmenting the attractiveness of human odour, and (2) attracting Anopheles mosquitoes in the absence of human odour, a two-choice assay using host decoy traps (HDTs) was used and evaluated using binomial generalized regression.
Traps baited with the HMBPP-induced odour blend attracted and caught both Anopheles arabiensis and Anopheles pharoensis females in a dose-dependent manner in the presence of background human odour, up to 2.5 times that of an unbaited trap. Given a choice between human odour and human odour laden with the HMBPP-induced odour blend, mosquitoes differentially preferred traps augmented with the HMBPP-induced odour blend, which caught twice as many female An. arabiensis. Traps baited with the HMBPP-induced odour blend but lacking the background of human odour were not effective in attracting and catching mosquitoes.
The findings of the present study revealed that the HMBPP-induced odour blend, when augmented with human body odour, is attractive to anopheline mosquitoes and could be used as a complementary vector control tool along with existing strategies.
疟原虫操纵其在蚊子和人类宿主之间的相互作用。与健康个体相比，感染配子体的患者会吸引按蚊，这种效果与增加有吸引力的挥发性线索的释放有关。这种气味驱动的操纵部分是由配子体特异性代谢物（E）-4-羟基-3-甲基-2-丁烯基焦磷酸（HMBPP）介导的，它诱导从红细胞中释放出更多的特定醛类和萜烯类物质，从而增强宿主寻求的蚊子的吸引力，蚊子是疟疾的传播媒介。本研究调查了 HMBPP 诱导的挥发物对野外条件下野生疟蚊对人类吸引力的影响。
在室内使用有诱饵的 Suna 陷阱，采用 4×6 拉丁矩形设计评估 HMBPP 诱导的气味混合物吸引疟蚊的效果。此外，为了评估 HMBPP 诱导的气味混合物在（1）增强人体气味的吸引力，以及（2）在没有人体气味的情况下吸引疟蚊方面的效果，使用宿主诱饵陷阱（HDT）进行了二选一的测定，并使用二项式广义回归进行了评估。
在有背景人体气味的情况下，HMBPP 诱导的气味混合物诱饵的陷阱以剂量依赖的方式吸引并捕获了阿拉伯按蚊和 Pharœnosoma 属疟蚊的雌性，多达未诱饵陷阱的 2.5 倍。在人体气味和人体气味负载 HMBPP 诱导的气味混合物之间进行选择时，蚊子更倾向于有 HMBPP 诱导的气味混合物的诱饵，这捕获了两倍多的雌性 An. arabiensis。缺乏人体气味背景的 HMBPP 诱导的气味混合物诱饵的陷阱对吸引和捕获蚊子没有效果。
本研究的结果表明，当与人体气味结合使用时，HMBPP 诱导的气味混合物对疟蚊具有吸引力，可作为与现有策略一起使用的补充性蚊虫控制工具。
