When used for the evaluation of drug efficacy against Psoroptes ovis, the diagnostic performance of different sampling strategies for a mite count reduction test (MCRT) remains unclear. In the present study, a novel simulation framework was constructed that accounted for relevant biological features of P. ovis infestations in cattle and that was parameterized with field data from 16 farms (154 animals). Second, this framework was applied to explore the impact of study specific factors (number of animals, number of sampled lesions, and number of scrapings per lesion) and biological factors (mite infestation intensity and size of lesions) on the diagnostic performance of MCRT. Its outcome provided a basis to determine the diagnostic performance of MCRT when it was applied according to the World Association for the Advancement in Veterinary Parasitology (WAAVP) and the European Medicine Agency (EMA) guidelines, and to formulate recommendations to ensure a good diagnostic performance of the MCRT. For both guidelines, the MCRT allowed to correctly detect (power 80%) reduced and normal efficacy when the therapeutic efficacy was <70%, and ≥95%, respectively. The results highlighted a reliable diagnostic performance of the MCRT when performed as recommended by WAAVP and EMA for the detection of normal drug efficacy. When used for the detection of reduced efficacy, therapeutic efficacies between 70% and 90% could not be detected with sufficient reliability. The diagnostic performance can be improved by increasing the total number of skin scrapings (increasing the number of animals, number of sampled lesions and/or number of samples per lesion). In order to help researchers and veterinarians to optimize the design of the MCRT to their field settings, the findings were translated into a simple tool.

当用于评估针对Psoroptes ovis的药物功效时，螨计数减少测试 (MCRT) 的不同采样策略的诊断性能仍不清楚。在本研究中，构建了一个新的模拟框架，该框架考虑了P. ovis 的相关生物学特征牛的感染情况，并使用来自 16 个农场（154 只动物）的现场数据进行参数化。其次，该框架用于探索研究特定因素（动物数量、采样病变数量和每个病变的刮屑数量）和生物因素（螨虫侵染强度和病变大小）对 MCRT 诊断性能的影响。其结果为根据世界兽医寄生虫学进步协会 (WAAVP) 和欧洲医学局 (EMA) 指南确定应用 MCRT 时的诊断性能提供了基础，并制定了建议以确保良好的诊断性能的 MCRT。对于这两个指南，当治疗效果 <70% 和 ≥95% 时，MCRT 允许正确检测（功率 80%）降低的和正常的疗效，分别。结果强调了当按照 WAAVP 和 EMA 的建议执行时，MCRT 具有可靠的诊断性能，以检测正常药物功效。当用于检测降低的疗效时，无法以足够的可靠性检测到 70% 至 90% 之间的治疗疗效。诊断性能可以通过增加皮肤刮擦的总数（增加动物数量、采样病变的数量和/或每个病变的样本数量）来提高。为了帮助研究人员和兽医根据他们的现场环境优化 MCRT 的设计，研究结果被转化为一个简单的工具。当用于检测降低的功效时，无法以足够的可靠性检测到 70% 至 90% 之间的治疗功效。诊断性能可以通过增加皮肤刮擦的总数（增加动物数量、采样病变的数量和/或每个病变的样本数量）来提高。为了帮助研究人员和兽医根据现场环境优化 MCRT 的设计，研究结果被转化为一个简单的工具。当用于检测降低的功效时，无法以足够的可靠性检测到 70% 至 90% 之间的治疗功效。诊断性能可以通过增加皮肤刮擦的总数（增加动物数量、采样病变的数量和/或每个病变的样本数量）来提高。为了帮助研究人员和兽医根据现场环境优化 MCRT 的设计，研究结果被转化为一个简单的工具。