Jonsson N N, Miller R J, Robertson J L
School of Veterinary Science, University of Queensland, Qld 4072, Australia.
Vet Parasitol. 2007 May 31;146(3-4):307-15. doi: 10.1016/j.vetpar.2007.02.031. Epub 2007 Apr 11.
Similar adult immersion tests (AITs) for acaricide susceptibility of Boophilus microplus were done in Texas, USA (Muñoz strain) and in Queensland, Australia (N-strain and Ultimo isolates). Engorged adult female ticks were immersed in one of a series of dilutions of commercial acaricide in water and then incubated at room temperature for 7 days. Data on oviposition were collected 7 days after exposure to acaricide and subjected to probit analysis. For most data, we observed poor fit to the probit model. Substantial differences in both LC50 and LC99 for the susceptible strains occurred between the respective laboratories and confidence intervals for all acaricides and all strains were unacceptably wide. For amitraz, the discriminating concentration (double the LC99.9 or LC99) recommended by FAO was 0.25%, but our estimates ranged from 0.46% to 9000%. For cypermethrin, the recommended DD was 0.0050%, with our estimates ranging from 0.00022% to 0.74%. For coumaphos the recommended DD was 0.50% but our estimates ranged from 0.66% to 130%. Finally, for moxidectin, the recommended DD was 0.10%, while our estimates ranged from <0.0001% to 5.9%. The method does not provide a means to discriminate between amitraz-susceptible and -resistant, nor between cypermethrin-susceptible and -resistant B. microplus.
在美国得克萨斯州（穆尼奥斯菌株）和澳大利亚昆士兰州（N菌株和乌尔蒂莫分离株）对微小牛蜱进行了类似的成蜱浸液试验（AITs）以检测其对杀螨剂的敏感性。饱血的成年雌性蜱虫被浸入一系列商业杀螨剂在水中的稀释液之一中，然后在室温下孵育7天。在接触杀螨剂7天后收集产卵数据并进行概率分析。对于大多数数据，我们观察到其与概率模型拟合不佳。各实验室之间易感菌株的LC50和LC99均存在显著差异，所有杀螨剂和所有菌株的置信区间都宽得令人无法接受。对于双甲脒，粮农组织推荐的鉴别浓度（LC99.9或LC99的两倍）为0.25%，但我们的估计值范围为0.46%至9000%。对于氯氰菊酯，推荐的鉴别剂量为0.0050%，我们的估计值范围为0.00022%至0.74%。对于蝇毒磷，推荐的鉴别剂量为0.50%，但我们的估计值范围为0.66%至130%。最后，对于莫昔克丁，推荐的鉴别剂量为0.10%，而我们的估计值范围为<0.0001%至5.9%。该方法无法区分双甲脒敏感和抗性的微小牛蜱，也无法区分氯氰菊酯敏感和抗性的微小牛蜱。
