Meza Felician C, Tenywa Frank C, Ashall Simon, Okumu Fredros O, Moore Sarah J, Tripet Frederic
Ifakara Health Institute, Environmental Health, and Ecological Science, P.O. Box 53, Ifakara, United Republic of Tanzania.
Centre for Applied Entomology and Parasitology, Keele University, Huxley Building, Staffordshire, UK.
Parasit Vectors. 2024 Dec 3;17(1):499. doi: 10.1186/s13071-024-06539-4.
Attractive targeted sugar baits (ATSBs) are promising new interventions that can complement existing vector control tools. However, reproducible and quantitative information on the level of attractiveness of ATSBs under field conditions is needed. Therefore, we customized camera traps for close-up imaging. We integrated them into a rugged ATSB monitoring station for day and nighttime recording of mosquitoes landing on the bait.
The camera traps were evaluated in a semifield system and then in the field in rural Tanzania. In semifield experiments, camera traps were set up in large cages (2 m × 5 m × 2 m) to record mosquitoes landing on an attractive sugar bait (ASB), a blank ASB, or 20% sucrose (w/v). Next, 198 mosquitoes (33 males and 33 females of Anopheles arabiensis, An. funestus and Aedes aegypti) were released into each large cage and allowed to seek a sugar meal for 72 h with a camera recording images of the mosquitoes present on the ASB at 1-min intervals. In the field, 16 camera traps were set in 16 households, 7 with ASB attractant, 7 with ASB blank, and 2 with 20% sucrose (w/v). Human landing catch (HLC) was performed on the same nights as the camera trap recordings.
Under semifield conditions, significantly more mosquitoes visited the ASBs than the blank baits, with An. funestus visiting more frequently than An. arabiensis. There were no significant differences between female and male An. arabiensis visits, but female An. funestus visited more than their conspecific males did. The duration of visits did not vary between the ASB and blank controls or between the mosquito species. Moreover, mosquitoes visited the ASB or sucrose equally, with An. arabiensis visiting the baits more than An. funestus. Compared with male mosquitoes, female mosquitoes visited the baits more often. There was no significant difference in visit duration between the species. In the field study, a mean of 70 An. arabiensis were caught per person per night on HLC, while 1 individual was caught per night on ASBs. There were significantly more visits by mosquitoes to the ASB than to the ASB blanks or sucrose solution, with more An. arabiensis visiting the baits than An. funestus or Culex quinquefasciatus. Significantly more females than males visited the baits of all the species. Again, the duration of visits was similar among An. arabiensis, An. funestus and C. quinquefasciatus. Aedes aegypti very rarely visited ASBs in the semifield experiments, and none were observed on baits in the field.
Using camera traps to record still images of mosquitoes on ASBs offers reliable, reproducible and quantitative information on their attractiveness in various environmental conditions. Thus, camera traps serve as effective tools for evaluating and improving ATSB technology.
有吸引力的靶向糖饵（ATSBs）是很有前景的新型干预措施，可补充现有的病媒控制工具。然而，需要关于ATSBs在野外条件下吸引力水平的可重复且定量的信息。因此，我们定制了用于特写成像的相机陷阱。我们将它们集成到一个坚固的ATSB监测站中，用于白天和夜间记录落在诱饵上的蚊子。
相机陷阱先在半野外系统中进行评估，然后在坦桑尼亚农村的野外进行评估。在半野外实验中，相机陷阱设置在大笼子（2米×5米×2米）中，以记录落在有吸引力的糖饵（ASB）、空白ASB或20%蔗糖（w/v）上的蚊子。接下来，将198只蚊子（阿拉伯按蚊、嗜人按蚊和埃及伊蚊各33只雄性和33只雌性）放入每个大笼子中，让它们寻找糖餐72小时，相机每隔1分钟记录ASB上出现的蚊子图像。在野外，16个相机陷阱设置在16户家庭中，7个装有ASB引诱剂，7个装有ASB空白对照，2个装有20%蔗糖（w/v）。在与相机陷阱记录相同的夜晚进行人饵诱捕（HLC）。
在半野外条件下，访问ASB的蚊子明显多于空白诱饵，嗜人按蚊的访问频率高于阿拉伯按蚊。阿拉伯按蚊的雌雄访问之间没有显著差异，但嗜人按蚊的雌性访问比同种雄性更多。访问持续时间在ASB和空白对照之间或不同蚊种之间没有差异。此外，蚊子访问ASB或蔗糖的情况相同，阿拉伯按蚊访问诱饵的次数多于嗜人按蚊。与雄性蚊子相比，雌性蚊子访问诱饵的频率更高。不同蚊种之间的访问持续时间没有显著差异。在野外研究中，HLC每人每晚平均捕获70只阿拉伯按蚊，而ASB每晚捕获1只。蚊子对ASB的访问明显多于ASB空白对照或蔗糖溶液，访问诱饵的阿拉伯按蚊多于嗜人按蚊或致倦库蚊。所有蚊种中，访问诱饵的雌性明显多于雄性。同样，阿拉伯按蚊、嗜人按蚊和致倦库蚊的访问持续时间相似。埃及伊蚊在半野外实验中很少访问ASB，在野外诱饵上未观察到。
使用相机陷阱记录ASB上蚊子的静态图像，可提供关于其在各种环境条件下吸引力的可靠、可重复且定量的信息。因此，相机陷阱是评估和改进ATSB技术的有效工具。
