Aelurostrongylus abstrusus is one of the most important respiratory nematodes of felines. Infections may lead to respiratory clinical signs with varying severity or even death, emphasizing the need for preventive treatment of cats with outdoor access to circumvent patent infections. Therefore, the preventive efficacy of a spot-on formulation of 280 mg/ml fluralaner and 14 mg/ml moxidectin (Bravecto® Plus spot-on solution for cats, MSD) against A. abstrusus was evaluated in a negative controlled, randomized and partially blinded efficacy study with 28 purpose-bred cats in a non-terminal design. In three different treatment regimes, the minimum recommended dose of 40 mg fluralaner and 2.0 mg moxidectin/kg bodyweight (BW) was administered once at 12, 8 or 4 weeks (study group G1, G2 and G3, respectively) prior to experimental infection with 300 third-stage A. abstrusus larvae, while G4 served as placebo-treated control. From 30 to 46 days post infection (dpi; SD 114 to 130), faeces were sampled to monitor first-stage larvae (L1) excretion for efficacy determination. Secondary efficacy criteria, including respiratory parameters, serological antibody levels and computed tomography (CT) findings, were assessed once before enrolment (SD −7 to −1) and before infection (SD 75 to 83). After infection, CT evaluation was performed once at 47–50 dpi (SD 131 to 134), and respiratory parameters and antibody levels were regularly assessed twice or once a week, respectively (1 up to 78 dpi, SD 85 up to 162). All animals in the control group excreted L1 by 33–37 dpi and remained positive throughout the study period from 41 to 46 dpi (SD 125 to 130). In the treatment groups, only one animal each of G1 and G2 excreted L1 at two consecutive days, and four cats of G1, two of G2 and three of G3 were positive on single occasions. While the geometric mean (GM) of the maximum number of excreted L1 per 5 g of faeces was 7380.89 in the control group (G4), GMs were significantly lower in the treatment groups with 1.63 in G1, 1.37 in G2 and 0.79 in G3. Thus, based on GMs, the reduction in excreted L1 exceeded 99.9% in all three treatment groups. Based on CT severity scores, all lungs of the animals of the control group showed severe pulmonary changes post infection, whereas lungs of the cats of the treatment groups were either unaltered (4 animals), mildly (11 animals), or moderately altered (5 animals). Moreover, seroconversion was observed in all cats of the control group, but not in those of the treatment groups. The combination of diagnostic methods used in this non-terminal study yielded coherent and reliable results. A single administration of Bravecto® Plus spot-on solution for cats was well tolerated and effective in the prevention of aelurostrongylosis for at least 12 weeks.

中文翻译：

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通过多种诊断方法评估 Bravecto® Plus 猫用点滴溶液（280 mg/ml fluralaner 和 14 mg/ml 莫昔克丁）预防猫科黑圆线虫感染的功效

深线虫是猫科动物最重要的呼吸道线虫之一。感染可能导致不同严重程度的呼吸道临床症状甚至死亡，强调需要对户外活动的猫进行预防性治疗，以避免明显的感染。因此，在阴性对照、随机和部分评估中，评估了 280 mg/ml fluralaner 和 14 mg/ml 莫昔克丁（Bravecto® Plus 猫用点滴溶液，MSD）点滴制剂对黑曲霉的预防功效。采用非最终设计对 28 只专门饲养的猫进行盲法功效研究。在三种不同的治疗方案中，在实验性感染前12周、8周或4周（分别为研究组G1、G2和G3）施用一次最小推荐剂量40 mg fluralaner和2.0 mg莫昔克丁/kg体重（BW）。 300 只第三阶段的深孔菌幼虫，而 G4 作为安慰剂处理的对照。感染后 30 至 46 天（dpi；SD 114 至 130），采集粪便样本以监测第一阶段幼虫 (L1) 的排泄情况，以确定疗效。次要疗效标准，包括呼吸参数、血清学抗体水平和计算机断层扫描（CT）结果，在入组前（SD -7至-1）和感染前（SD 75至83）评估一次。感染后，在47-50 dpi（SD 131至134）进行一次CT评估，并分别定期评估呼吸参数和抗体水平两次或每周一次（1至78 dpi，SD 85至162）。对照组的所有动物均在 33-37 dpi 时排泄 L1，并在 41 至 46 dpi（SD 125 至 130）的整个研究期间保持阳性。在治疗组中，G1和G2各只有一只动物连续两天排泄L1，并且G1的四只猫、G2的两只猫和G3的三只猫单次呈阳性。对照组（G4）每 5 克粪便排出的 L1 最大数量的几何平均值（GM）为 7380.89，而治疗组的 GM 明显较低，G1 为 1.63，G2 为 1.37，G3 为 0.79。因此，根据 GM，所有三个治疗组中 L1 排泄量的减少均超过 99.9%。根据 CT 严重程度评分，对照组动物的所有肺部在感染后均显示出严重的肺部变化，而治疗组猫的肺部要么未改变（4 只动物），要么轻度改变（11 只动物），要么中度改变（5 只动物）。动物）。此外，在对照组的所有猫中均观察到血清转化，但在治疗组的猫中未观察到。这项非最终研究中使用的诊断方法的组合产生了一致且可靠的结果。猫单次施用 Bravecto® Plus 点滴溶液具有良好的耐受性，并且可有效预防无圆线虫病至少 12 周。