Could insecticide-treated cattle reduce Afrotropical malaria transmission?: Effects of deltamethrin-treated Zebu on Anopheles arabiensis behaviour and survival in Ethiopia
Could insecticide-treated cattle reduce Afrotropical malaria transmission?: Effects of deltamethrin-treated Zebu on Anopheles arabiensis behaviour and survival in Ethiopia
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DOI：
10.1111/j.0269-283x.2004.00525.x
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发表时间：
2004-12-01
影响因子：
1.9
通讯作者：
Gibson, G
中科院分区：
文献类型：
--
作者：
Habtewold, T;Prior, A;Gibson, G
阿拉伯按蚊（Anopheles arabiensis Patton）（双翅目：蚊科）是非洲热带地区最广泛的疟疾媒介。因为安。阿拉伯蜱虫既容易以牛为食，也容易以人为食，因此，对牛进行驱虫-用于控制采采蝇（双翅目：舌蚊科）和蜱（阿卡里：硬蜱科）-可能同时影响这种蚊子的疟疾媒介能力。因此，我们在埃塞俄比亚南部进行了田间试验，以确定是否有Zebu牛（Bos indicus L.）用广泛用于控制蜱和采采蝇的1%溴氰菊酯浇泼式拟除虫菊酯制剂处理，将对An有效。阿拉伯按蚊或导致雌蚊更频繁地以人类为食，这是由于行为上避免使用过草甘膦的牛。接触生物测定（3分钟暴露）表明，杀虫剂对在处理牛胁腹上取食的蚊子保持有效约1个月（杀灭率> 50%）。一种新的行为分析表明，安。Arabiensis很容易在接受过甜菜碱处理的牛身上取食，并且在接受过甜菜碱处理的牛存在的情况下不会转移到人类宿主身上。血粉的DNA指纹图谱显示，安。阿拉伯蜱自然最常以较年长的动物为食，这与只对较年长的牛施用杀虫剂的既定做法一致，同时允许未经治疗的较年轻的动物获得对蜱传播的感染的免疫力。这些令人鼓舞的结果被发现> 90%的An。arabiensis、阿拉伯隐翅虫An. pharoensis和安氏按蚊（An.雌性黑腹蛛以牛的腿为食，沿着动物的背部离浇泼施用部位最远，并且由于风化，处理可能残留最少。对自然取食驱虫牛的蚊子的观察表明，大多数野生雌性按蚊在宿主动物身上停留不到1分钟，取食驱虫牛的平均持续时间明显缩短，杀虫剂的有效寿命仅为1周。因此，每月对牛施用溴氰菊酯（通常用于控制采采蝇和蜱）不太可能对An有效。arabiensis种群或其媒介能力。即便如此，通过有选择地将杀虫剂涂在牛腿上，似乎可以对按蚊产生更大的影响。
Anopheles arabiensis Patton (Diptera: Culicidae) is the most widespread vector of malaria in the Afrotropical Region. Because An. arabiensis feeds readily on cattle as well as humans, the insecticide-treatment of cattle - as employed to control tsetse (Diptera: Glossinidae) and ticks (Acari: Ixodidae) - might simultaneously affect the malaria vectorial capacity of this mosquito. Therefore, we conducted field experiments in southern Ethiopia to establish whether Zebu cattle (Bos indicus L.) treated with a pour-on pyrethroid formulation of 1% deltamethrin, widely used to control ticks and tsetse, would be effective against An. arabiensis or cause the female mosquitoes to feed more frequently on humans, due to behavioural avoidance of insecticide-treated cattle. Contact bioassays (3 min exposure) showed that the insecticide remained effective for about 1 month (kill rate > 50%) against mosquitoes feeding on the flanks of treated cattle. A novel behavioural assay demonstrated that An. arabiensis readily fed on insecticide-treated cattle and were not deflected to human hosts in the presence of treated cattle. DNA-fingerprinting of bloodmeals revealed that An. arabiensis naturally feeds most frequently on older animals, consistent with the established practice of applying insecticide only to older cattle, while allowing younger untreated animals to gain immunity against infections transmitted by ticks. These encouraging results were tempered by finding that > 90% of An. arabiensis, An. pharoensis and An. tenebrosus females feed on the legs of cattle, farthest from the site of pour-on application along the animal's back and where the treatment may be least residual due to weathering. Observations of mosquitoes feeding naturally on insecticide-treated cattle showed that the majority of wild female anophelines alighted on the host animal for less than 1 min to feed, with significantly shorter mean duration of feeding bouts on insecticide-treated animals, and the effective life of the insecticide was only 1 week. Thus the monthly application of deltamethrin to cattle, typically used to control tsetse and ticks, is unlikely to be effective against An. arabiensis populations or their vectorial capacity. Even so, it seems likely that far greater impact on anopheline mosquitoes could be achieved by applying insecticide selectively to the legs of cattle.