Insecticidal effects of deltamethrin in laboratory and field populations of Culicoides species: how effective are host-contact reduction methods in India?
Insecticidal effects of deltamethrin in laboratory and field populations of Culicoides species: how effective are host-contact reduction methods in India?
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DOI：
10.1186/s13071-017-1992-0
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发表时间：
2017-01-31
影响因子：
3.2
通讯作者：
Logan JG
中科院分区：
文献类型：
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作者：
De Keyser R;Cassidy C;Laban S;Gopal P;Pickett JA;Reddy YK;Prasad M;Prasad G;Chirukandoth S;Senthilven K;Carpenter S;Logan JG
蓝舌病病毒（BTV）是由库蠓叮咬蠓传播，并导致蓝舌病（BT），这是一种主要在绵羊中观察到的临床疾病。BT对印度的自给农民产生了不利影响，高流行病的爆发影响了该国南部各州的小农场。在这项研究中，我们建立了一个可靠的方法来测试溴氰菊酯对库蠓的毒性作用，然后比较溴氰菊酯与印度农民使用的传统控制方法。最初使用一种嗜nubeculosus Meigen库蠓定殖菌株和一种改良的世界卫生组织暴露试验检测了溴氰菊酯的影响。然后将该方法应用于库蠓属的野外种群。在印度田间种群的分布情况。印度的尖口线虫对溴氰菊酯的LC 50（0.012 ± 0.009%）高于实验室饲养的银汉锦鸡儿（0.0013 ± 0.0002%）。C的暴露。在较高的环境温度下，nubeculosus对溴氰菊酯的击倒率较高，但在暴露后24小时死亡率较低。行为测定C. WHO管中的nubeculosus提供了溴氰菊酯引起的接触刺激性和空间驱避性的证据。然而，在印度进行的田间试验没有提供溴氰菊酯具有驱避或毒性作用的证据。传统的方法，如应用印楝油和燃烧印楝叶也没有提供保护。我们的研究表明，在印度野外采集的库蠓对溴氰菊酯的敏感性低于实验室饲养的库蠓。nubeculosus和传统的昆虫控制方法不能为绵羊提供保护。这些对溴氰菊酯的低敏感性水平以前在库蠓田间种群中未记录过，表明对合成拟除虫菊酯具有抗性。除了接种疫苗外，可能还需要其他昆虫控制方法来保护印度牲畜免受BTV传播。本文的在线版本（doi：10.1186/s13071-017-1992-0）包含补充材料，可供授权用户使用。
Bluetongue virus (BTV) is transmitted by Culicoides biting midges and causes bluetongue (BT), a clinical disease observed primarily in sheep. BT has a detrimental effect on subsistence farmers in India, where hyperendemic outbreaks impact on smallholdings in the southern states of the country. In this study, we establish a reliable method for testing the toxic effects of deltamethrin on Culicoides and then compare deltamethrin with traditional control methods used by farmers in India. Effects of deltamethrin were initially tested using a colonised strain of Culicoides nubeculosus Meigen and a modified World Health Organisation exposure assay. This method was then applied to field populations of Culicoides spp. in India. The field population of C. oxystoma in India had a greater LC50 (0.012 ± 0.009%) for deltamethrin than laboratory-reared C.nubeculosus (0.0013 ± 0.0002%). Exposure of C. nubeculosus to deltamethrin at higher ambient temperatures resulted in greater rates of knockdown but a lower mortality rate at 24 h post-exposure. Behavioural assays with C. nubeculosus in WHO tubes provided evidence for contact irritancy and spatial repellence caused by deltamethrin. The field experiments in India, however, provided no evidence for repellent or toxic effects of deltamethrin. Traditional methods such as the application of neem oil and burning of neem leaves also provided no protection. Our study demonstrates that field-collected Culicoides in India are less susceptible to deltamethrin exposure than laboratory-bred C. nubeculosus and traditional methods of insect control do not provide protection to sheep. These low levels of susceptibility to deltamethrin have not been recorded before in field populations of Culicoides and suggest resistance to synthetic pyrethrioids. Alternative insect control methods, in addition to vaccination, may be needed to protect Indian livestock from BTV transmission. The online version of this article (doi:10.1186/s13071-017-1992-0) contains supplementary material, which is available to authorized users.