Infection Biology, University of Liverpool Institute of Infection and Global Health, Liverpool, UK.
Moredun Research Institute, Midlothian, UK.
Vet Rec. 2019 May 11;184(19):589. doi: 10.1136/vr.105128. Epub 2019 Feb 2.
Options for diagnosing infection in groups of cattle are limited. Increasing the opportunities for herd-level diagnosis is important for disease monitoring, making informed treatment decisions and for flukicide efficacy testing. The sensitivity of a simple sedimentation method based on composite faecal samples for the detection of fluke eggs in cattle was assessed through a combination of experimental and statistical modelling techniques. Initially, a composite sample method previously developed for sheep was used to investigate the sensitivity of composite sample testing compared with individual counts on the same samples in cattle. Following this, an optimised, validated, qualitative (presence-absence) composite sample field test was developed for cattle. Results showed that fluke egg counts obtained from a composite sample are representative of those expected from individual counts. The optimal sampling strategy was determined to be 10 individual 10 g samples (100 g composite sample) from which a 10 g subsample is taken for sedimentation. This method yielded a diagnostic sensitivity of 0.69 (95 per cent CI 0.5 to 0.85). These results demonstrate the validity and usefulness of a composite faecal egg sedimentation method for use in the diagnosis and control of in groups of cattle, with the caveat that a negative test should be followed up with a second test due to limitations relating to test sensitivity.
在牛群中诊断感染的方法有限。增加群体水平诊断的机会对于疾病监测、做出明智的治疗决策和氟虫腈疗效测试非常重要。本研究通过结合实验和统计建模技术，评估了一种基于复合粪便样本的简单沉淀方法对牛类吸虫卵检测的敏感性。最初，使用先前为绵羊开发的复合样本方法，研究了复合样本检测与牛类相同样本的个体计数之间的敏感性。在此之后，为牛类开发了一种优化、验证、定性（存在/不存在）的复合样本现场测试。结果表明，复合样本中获得的吸虫卵计数与个体计数中预期的计数具有代表性。确定的最佳采样策略是从 10 个个体的 10g 样本（100g 复合样本）中采集 10g 进行沉淀。该方法的诊断灵敏度为 0.69（95%置信区间为 0.5 至 0.85）。这些结果证明了复合粪便卵沉淀方法在牛群中诊断和控制中的有效性和实用性，需要注意的是，由于测试敏感性的限制，阴性测试后应进行第二次测试。
