Auburn University, Auburn, AL, USA.
Vet Parasitol. 2010 Mar 25;168(3-4):312-7. doi: 10.1016/j.vetpar.2009.11.023. Epub 2009 Dec 1.
The efficacy of spinosad against adult fleas (Ctenocephalides felis) on dogs was evaluated in three controlled, blinded studies. One study was conducted to determine speed of kill on experimentally infested dogs. Two additional studies were designed to assess the efficacy of spinosad in preventing environmental contamination with flea eggs (USA study and EU study). An additional objective of the USA study was to assess the effects of skin and hair-coat debris from spinosad-treated dogs on eggs and larvae of C. felis. Dogs were randomly allocated to treatment with beef-flavored spinosad tablets, administered orally at a minimum dosage of 30mg/kg, or placebo. In the first study, speed of kill was determined by flea comb counts performed at 0.5, 1, 2, 4, 8, 12, 24 and 48h after spinosad treatment. Reductions in geometric mean flea counts for spinosad-treated dogs, compared to placebo were 53.7% at 0.5h, 64.2% at 1h, 85.8% at 2h and 100% at 4 through 48h post-treatment (p<0.05 at 1h and beyond). In the 2 flea egg production studies, dogs were treated (spinosad or placebo) once on day 0, infested with 600 fleas approximately 3h post-treatment and reinfested with approximately 600 fleas at intervals over 1 month. Flea eggs were collected starting at approximately 72h after each infestation. Eggs were examined for any effects of spinosad on egg viability. Efficacy of spinosad was also evaluated against environmental eggs and larvae exposed to canine hair-coat debris collected on days 3, 7, 14, 21, and 30. Spinosad was highly effective in reducing flea egg production (>99.8% across the entire study period) compared to control dogs in both egg collection studies. Insufficient numbers of eggs were recovered from spinosad-treated dogs to determine the viability of those eggs. There was no evidence of any effect on environmental flea stages, indicating that spinosad was not present in the skin debris of spinosad-treated dogs. The capability of spinosad to quickly kill adult fleas, and to greatly reduce egg production following challenge with high numbers of adult fleas is important in breaking the flea life cycle and preventing the introduction and establishment of new flea infestations in the household.
三项对照、盲法研究评估了多杀菌素对犬跳蚤（猫栉首蚤）成虫的疗效。一项研究旨在确定跳蚤的杀灭速度，实验动物为感染跳蚤的犬。另外两项研究旨在评估多杀菌素预防跳蚤卵（美国研究和欧盟研究）环境污染的效果。美国研究的另一个目的是评估多杀菌素处理犬的皮肤和毛发碎屑对猫栉首蚤卵和幼虫的影响。犬被随机分为多杀菌素牛肉味咀嚼片组（口服最低剂量 30mg/kg）和安慰剂组。在第一项研究中，在多杀菌素处理后 0.5、1、2、4、8、12、24 和 48 小时，通过梳检跳蚤计数来确定杀灭速度。与安慰剂组相比，多杀菌素处理犬的跳蚤几何均数减少率在 0.5 小时为 53.7%，1 小时为 64.2%，2 小时为 85.8%，4 至 48 小时为 100%（1 小时及以后有统计学差异）。在两项跳蚤卵产生研究中，犬于第 0 天接受一次处理（多杀菌素或安慰剂），处理后约 3 小时用 600 只跳蚤感染，在 1 个月内间隔时间再用 600 只跳蚤重复感染。在每次感染后约 72 小时开始收集跳蚤卵。检查多杀菌素对卵活力的影响。还评估了多杀菌素对暴露于犬毛发碎屑环境中的卵和幼虫的效果，毛发碎屑在第 3、7、14、21 和 30 天采集。在两项卵收集研究中，与对照犬相比，多杀菌素能极有效地降低跳蚤卵的产生（整个研究期间>99.8%）。从多杀菌素处理犬身上回收的卵数量不足，无法确定这些卵的活力。多杀菌素处理犬的皮肤碎屑未检测到环境中跳蚤各阶段的任何影响，表明多杀菌素不存在于皮肤碎屑中。多杀菌素能迅速杀灭成年跳蚤，并在大量成年跳蚤挑战后极大地降低卵的产生，这对于打破跳蚤生命周期以及防止家庭中引入和建立新的跳蚤感染非常重要。
