Johnson G D, Goosey H B, Rolston M G, Miller W L, Hokit D G, Redden R R, Kott R W
Department of Animal and Range Sciences, Montana State University, Bozeman, MT 50717, USA.
J Am Mosq Control Assoc. 2013 Jun;29(2):146-53. doi: 10.2987/12-6322R.1.
A rise in the incidence of mosquito-transmitted Cache Valley virus (CVV) in lambs in 2011 prompted a study to evaluate on-animal pyrethroid insecticides to reduce mosquito attacks on sheep. Using enclosure traps for 1 night per wk for 6 wk, we compared engorgement rates of mosquitoes given the opportunity to feed on untreated sheep and sheep treated with 1 Python insecticide ear tag (containing 10% zeta-cypermethrin and 20% piperonyl butoxide) per animal or 2 synergized permethrin body spray treatments (containing 2.5% permethrin and 2.5% piperonyl butoxide). During the 6-wk study, 18,920 mosquitoes were collected in the animal-baited enclosure traps. Thirteen species were identified from these collections with the floodwater species Aedes increpitus and Ae. idahoensis making up 68% of the total. Potential CVV vector species, making up 25% of the samples, included Ae. vexans, Ae. dorsalis, Culex tarsalis, and Culiseta inornata. Traps baited with untreated sheep collected 9,701 mosquitoes with 65% of these engorged. Traps baited with sheep treated with Python ear tags or permethrin spray collected 4,034 and 4,555, respectively, with engorgement rates of 23% and 35%. Blood feeding on ear-tagged sheep was significantly reduced by as much as 90% compared to the untreated sheep, and protection lasted 4 wk or longer. Permethrin spray treatments were most effective within 24 h after application and provided better protection against Ae. dorsalis than the Python tag. Effectiveness of the permethrin spray diminished 1 wk after the 2nd application was made. The effect of these treatments appeared to be repellency because negligible mosquito mortality was observed at the time of collection. Further evaluation of these insecticides under conditions of natural exposure to a mosquito-borne pathogen is warranted.
2011年，羔羊中蚊媒传播的卡什谷病毒（CVV）发病率上升，促使开展一项研究，评估用于动物的拟除虫菊酯类杀虫剂，以减少蚊子对绵羊的叮咬。我们每周使用围栏诱捕器1晚，持续6周，比较了有机会叮咬未处理绵羊以及每只动物使用1个派松杀虫剂耳标（含10%高效氯氟氰菊酯和20%增效醚）或2次增效氯菊酯体表喷雾处理（含2.5%氯菊酯和2.5%增效醚）的绵羊的蚊子饱食率。在为期6周的研究中，在动物诱饵围栏诱捕器中收集到18920只蚊子。从这些收集物中鉴定出13个物种，其中洪水型物种伊氏伊蚊和爱达荷伊蚊占总数的68%。构成样本25%的潜在CVV传播媒介物种包括骚扰伊蚊、背点伊蚊、跗斑库蚊和无饰库蚊。用未处理绵羊作为诱饵的诱捕器收集到9701只蚊子，其中65%饱食。用派松耳标或氯菊酯喷雾处理的绵羊作为诱饵的诱捕器分别收集到4034只和4555只蚊子，饱食率分别为23%和35%。与未处理的绵羊相比，叮咬带耳标的绵羊的吸血量显著减少多达90%，且保护持续4周或更长时间。氯菊酯喷雾处理在施用后24小时内最有效，对背点伊蚊的防护效果优于派松耳标。第二次施用氯菊酯喷雾1周后，其效果减弱。这些处理的效果似乎是驱避作用，因为在收集时观察到的蚊子死亡率可忽略不计。有必要在自然暴露于蚊媒病原体的条件下对这些杀虫剂进行进一步评估。
