Rajendra Memorial Research Institute of Medical Sciences, Patna, India.
PLoS Negl Trop Dis. 2010 Oct 26;4(10):e859. doi: 10.1371/journal.pntd.0000859.
To investigate the DDT and deltamethrin susceptibility of Phlebotomus argentipes, the vector of Leishmania donovani, responsible for visceral leishmaniasis (VL), in two countries (India and Nepal) with different histories of insecticide exposure.
Standard WHO testing procedures were applied using 4% DDT and 0.05% deltamethrin impregnated papers. The effect of the physiological status (fed and unfed) of females on the outcome of the bioassays was assessed and the optimal time of exposure for deltamethrin was evaluated on a colony population. Field populations from both countries were tested.
Fed and unfed females responded in a similar way. For exposure time on field samples 60 min was adopted for both DDT and deltamethrin. In Bihar, knockdown and mortality with DDT was respectively 20 and 43%. In Nepal almost all sand flies were killed, except at the border with Bihar (mortality 62%). With 0.05% deltamethrin, between 96 and 100% of the sand flies were killed in both regions.
Based on literature and present data 4% DDT and 0.05% deltamethrin seem to be acceptable discriminating concentrations to separate resistant from susceptible populations. Resistance to DDT was confirmed in Bihar and in a border village of Nepal, but the sand flies were still susceptible in villages more inside Nepal where only synthetic pyrethroids are used for indoor spraying. The low effectiveness of indoor spraying with DDT in Bihar to control VL can be partially explained by this resistance hence other classes of insecticides should be tested. In both countries P. argentipes sand flies were susceptible to deltamethrin.
调查印度和尼泊尔两个国家（印度和尼泊尔）中不同杀虫剂暴露史的致内脏利什曼病（VL）的白蛉按蚊（Phlebotomus argentipes）对滴滴涕和溴氰菊酯的敏感性。
采用 4%滴滴涕和 0.05%溴氰菊酯浸渍纸，应用世界卫生组织（WHO）标准检测程序。评估了雌蚊生理状态（进食和未进食）对生物测定结果的影响，并评估了在一个种群中溴氰菊酯的最佳暴露时间。检测了来自这两个国家的现场种群。
进食和未进食的雌性反应相似。对于现场样本的暴露时间，分别采用 60 分钟的 DDT 和溴氰菊酯。在比哈尔邦，滴滴涕的击倒和死亡率分别为 20%和 43%。在尼泊尔，除了与比哈尔邦接壤的地区（死亡率为 62%）外，几乎所有的白蛉都被杀死。在这两个地区，用 0.05%溴氰菊酯，96%至 100%的白蛉都被杀死。
根据文献和目前的数据，4%滴滴涕和 0.05%溴氰菊酯似乎是可接受的区分浓度，可用于分离抗性和敏感种群。在比哈尔邦和尼泊尔边境的一个村庄证实了对滴滴涕的抗性，但在尼泊尔境内的村庄，由于只使用合成拟除虫菊酯进行室内喷洒，白蛉仍对其敏感。在比哈尔邦，室内喷洒滴滴涕控制 VL 的效果不佳，部分原因是这种抗性，因此应该测试其他类别的杀虫剂。在这两个国家，白蛉按蚊对溴氰菊酯均敏感。
