Six Robert H, Everett William R, Chapin Sara, Mahabir Sean P
Zoetis, Veterinary Medicine Research and Development, 333 Portage St, Kalamazoo, MI, 49007, USA.
BerTek, Inc., PO Box 606, Greenbrier, AR, 72058, USA.
Parasit Vectors. 2016 Feb 19;9:98. doi: 10.1186/s13071-016-1378-8.
The lone star tick, Amblyomma americanum, infests dogs and cats in North America and is the vector of the pathogens that cause monocytic and granulocytic ehrlichiosis in dogs and humans. A parasiticide's speed of kill is important to minimize the direct and deleterious effects of tick infestation and especially to reduce the risk of transmission of tick-borne pathogens. In this study, speed of kill of a novel orally administered isoxazoline parasiticide, sarolaner (Simparica chewable tablets), against A. americanum on dogs was evaluated and compared with afoxolaner (NexGard) for 5 weeks following a single oral dose.
Based on pretreatment tick counts, 24 dogs were randomly allocated to treatment with sarolaner (2 to 4 mg/kg), afoxolaner (2.5 to 6.8 mg/kg) or a placebo. Dogs were examined and live ticks counted at 8, 12, and 24 h after treatment and subsequent re-infestations on Days 7, 14, 21, 28, and 35. Efficacy was determined at each time point relative to counts for placebo dogs.
A single oral dose of sarolaner provided 100 % efficacy within 24 h of treatment, and consistently provided >90% efficacy against subsequent weekly re-infestations with ticks to Day 28. Significantly more live ticks were recovered from afoxolaner-treated dogs than from sarolaner-treated dogs at 24 h after infestation from Day 7 through Day 35 (P ≤ 0.0247). At 24 h, efficacy of afoxolaner declined to less than 90% from Day 14 to the end of the study. There were no adverse reactions to treatment.
In this controlled laboratory evaluation, sarolaner had a faster speed of kill against A. americanum ticks than afoxolaner. The rapid and consistent kill of ticks by sarolaner within 24 h after a single oral dose over 28 days, suggests this treatment will provide highly effective and reliable control of ticks over the entire treatment interval, and could help reduce the risk of transmission of tick-borne pathogens by A. americanum.
美洲钝眼蜱（Amblyomma americanum）寄生在北美的犬猫身上，是导致犬类和人类单核细胞性埃立克体病和粒细胞性埃立克体病的病原体的传播媒介。杀蜱剂的杀灭速度对于将蜱虫寄生的直接有害影响降至最低，尤其是降低蜱传病原体传播风险十分重要。在本研究中，评估了一种新型口服异恶唑啉类杀蜱剂沙罗拉纳（Simparica咀嚼片）对犬身上美洲钝眼蜱的杀灭速度，并在单次口服给药后5周内与阿福拉纳（NexGard）进行比较。
根据治疗前蜱虫计数，将24只犬随机分配接受沙罗拉纳（2至4mg/kg）、阿福拉纳（2.5至6.8mg/kg）或安慰剂治疗。在治疗后8、12和24小时以及随后第7、14、21、28和35天再次感染后对犬进行检查并计数存活蜱虫。相对于安慰剂组犬的计数，在每个时间点确定疗效。
单次口服沙罗拉纳在治疗后24小时内提供了100%的疗效，并且在第28天之前对随后每周再次感染的蜱虫始终提供>90%的疗效。从第7天到第35天，在感染后24小时，从阿福拉纳治疗的犬身上回收的存活蜱虫明显多于沙罗拉纳治疗的犬（P≤0.0247）。在24小时时，从第14天到研究结束，阿福拉纳的疗效降至90%以下。治疗无不良反应。
在本对照实验室评估中，沙罗拉纳对美洲钝眼蜱的杀灭速度比阿福拉纳快。沙罗拉纳在单次口服给药后24小时内对蜱虫的快速且持续杀灭作用，表明该治疗方法在整个治疗期间将提供高效且可靠的蜱虫控制，并有助于降低美洲钝眼蜱传播蜱传病原体的风险。
