Mehlhorn H, Hansen O, Mencke N
Department of Parasitology, Heinrich-Heine University, Düsseldorf, Germany.
Parasitol Res. 2001 Mar;87(3):198-207. doi: 10.1007/pl00008575.
The effects of three insecticides (fipronil, imidacloprid and selamectin) on developmental stages of cat fleas (Ctenocephalides felis) were studied in vivo, in vitro and by means of light and electron microscopy. The results were documented by video. Adult fleas were attached to the skin of dogs that had been treated 7 days before with one of the three compounds. Furthermore, adult fleas were exposed exclusively to the hair and skin debris of such treated dogs or were placed on filter papers that had been impregnated with one of these three compounds or with the blood of treated dogs. Larval fleas were exposed to hair of treated dogs, to debris obtained by combing treated dogs, to dried blood samples of treated dogs or were placed onto filter papers impregnated with one of the three compounds. In these experiments with adult and larval fleas, it was noted that none of the three insecticides had a repellent effect on adult or larval fleas. Imidacloprid was the only compound that acted exclusively by body contact, and was apparently taken up by adult and larval fleas via the thin, non-sclerotized intersegmental membranes of the flea's body, shown when flea stages were exposed to hairs taken from dogs treated with one of the compounds or placed onto drug-impregnated filter papers. Imidacloprid killed larvae and adult fleas within 1 h, while it took at least 24 h until all adult fleas had died on fipronil- or selamectin-treated dogs, thus allowing longer feeding periods, increasing the risk of transmission of flea-derived diseases. Flea larvae covered with debris from dogs topically treated 7 days before with fipronil, imidacloprid or selamectin died, like the untreated control, within 16-28 h after exposure. This was, however, probably mainly due to a drying effect. Adult and larval fleas exposed to filter papers impregnated with the blood of treated dogs survived longer than 7 days, as did the untreated controls. All three drugs apparently acted on nerves and muscles and thus stopped motility.
通过体内、体外实验以及光学和电子显微镜观察，研究了三种杀虫剂（氟虫腈、吡虫啉和塞拉菌素）对猫栉首蚤发育阶段的影响。实验结果通过视频记录。将成年跳蚤附着在7天前用三种化合物之一处理过的狗的皮肤上。此外，成年跳蚤仅接触此类处理过的狗的毛发和皮肤碎屑，或放置在浸渍有这三种化合物之一或处理过的狗血的滤纸上。幼虫跳蚤接触处理过的狗的毛发、梳理处理过的狗得到的碎屑、处理过的狗的干血样本，或放置在浸渍有这三种化合物之一的滤纸上。在这些针对成年和幼虫跳蚤的实验中，注意到这三种杀虫剂对成年或幼虫跳蚤均无驱避作用。吡虫啉是唯一仅通过身体接触起作用的化合物，成年和幼虫跳蚤显然是通过跳蚤身体薄的、未硬化的节间膜吸收该化合物的，当跳蚤阶段接触用其中一种化合物处理过的狗身上的毛发或放置在药物浸渍的滤纸上时即可显示此情况。吡虫啉在1小时内杀死幼虫和成年跳蚤，而在氟虫腈或塞拉菌素处理过的狗身上，至少需要24小时所有成年跳蚤才会死亡，从而使跳蚤有更长的进食时间，增加了跳蚤传播疾病的风险。用氟虫腈、吡虫啉或塞拉菌素局部处理7天前的狗身上的碎屑覆盖的跳蚤幼虫，与未处理的对照一样，在接触后16 - 28小时内死亡。然而，这可能主要是由于干燥作用。接触浸渍有处理过的狗血的滤纸的成年和幼虫跳蚤存活时间超过7天，未处理的对照也是如此。所有三种药物显然作用于神经和肌肉，从而停止活动。
