International Centre of Insect Physiology and Ecology, GPO, Nairobi, Kenya.
Malar J. 2010 Jan 6;9:6. doi: 10.1186/1475-2875-9-6.
The search for a standard human surrogate in the form of a synthetic mosquito attractant has been the goal of many laboratories around the world. Besides alleviating the occupational risk subjected to volunteers participating in vector surveillance and control, discovery of potent attractants underpins the development and deployment of mass trapping devices for controlling mosquito-borne diseases.
A dual-port olfactometer was used to assess behavioural responses of female Anopheles gambiae mosquitoes towards synthetic versus natural (whole human emanations and worn socks) attractants. The synthetic attractants included a standard blend consisting of ammonia, carbon dioxide and water; and Ifakara blend 1 (IB1) consisting of various aliphatic carboxylic acids. Natural attractants were obtained from two males known to be less and highly attractive (LA and HA, respectively) to the mosquitoes. Mosquito responses to the volunteers' worn socks were also investigated. The effect of heat (25-27 degrees C) and moisture (75-85%) on the mosquito behavioural responses was determined.
A significantly higher proportion of mosquitoes was attracted to each volunteer when compared to the standard blend. Whereas the proportion of mosquitoes attracted to person LA versus IB1 (49% versus 51%, respectively; P = 0.417) or his worn socks did not differ (61% versus 39%, respectively; P = 0.163), far more mosquitoes were attracted to person HA relative to IB1 (96% versus 4%; P = 0.001) or his worn socks (91% versus 9%; P = 0.001). Person HA attracted a significantly higher proportion of mosquitoes than his worn socks, the standard blend and IB1 when these were augmented with heat, moisture or both (P = 0.001). Similar results were obtained with person LA except that the proportion of mosquitoes attracted to him versus his worn sock augmented with heat (P = 0.65) or IB1 augmented with heat and moisture (P = 0.416) did not differ significantly.
These findings indicate that olfactory cues are key mediators of the mosquito host-seeking process and that heat and moisture play a minor role. The need for a standard, highly stringent positive control for screening synthetic attractants is strongly highlighted.
寻找一种标准化的人类替代物，即合成的蚊子引诱剂，一直是世界各地许多实验室的目标。除了减轻参与蚊虫监测和控制的志愿者所面临的职业风险外，发现有效的引诱剂还为控制蚊媒疾病的大规模诱捕装置的开发和部署提供了基础。
使用双端口嗅觉仪评估了雌性疟蚊对合成引诱剂（包括氨、二氧化碳和水的标准混合物以及包含各种脂肪族羧酸的 Ifakara 混合物 1）与天然引诱剂（整个人体散发物和穿用的袜子）的行为反应。天然引诱剂取自两个对蚊子来说吸引力较低和较高的男性（分别为 LA 和 HA）。还研究了蚊子对志愿者穿用的袜子的反应。确定了热（25-27 摄氏度）和湿度（75-85%）对蚊子行为反应的影响。
与标准混合物相比，每一位志愿者都显著增加了蚊子的吸引力。虽然与 IB1 相比，LA 对蚊子的吸引力比例（分别为 49%和 51%，P = 0.417）或他的穿用袜子没有差异（分别为 61%和 39%，P = 0.163），但与 IB1 相比，更多的蚊子被 HA 吸引（96%对 4%，P = 0.001）或他的穿用袜子（91%对 9%，P = 0.001）。当增加热量、湿度或两者时，与标准混合物和 IB1 相比，HA 吸引的蚊子比例显著更高（P = 0.001）。LA 也得到了类似的结果，但与穿用袜子相比，他对热（P = 0.65）或热和湿度（P = 0.416）增强的 IB1 的吸引力没有显著差异。
这些发现表明，嗅觉线索是蚊子寻找宿主过程的关键调节因素，而热量和湿度的作用较小。强烈强调需要一种标准化的、高度严格的阳性对照来筛选合成引诱剂。
