Paras Kelsey L, George Melissa M, Vidyashankar Anand N, Kaplan Ray M
University of Georgia College of Veterinary Medicine Department of Infectious Diseases, 501 D.W. Brooks Dr. Athens, GA, 30602, United States.
University of Georgia College of Veterinary Medicine Department of Infectious Diseases, 501 D.W. Brooks Dr. Athens, GA, 30602, United States.
Vet Parasitol. 2018 Jun 15;257:21-27. doi: 10.1016/j.vetpar.2018.05.015. Epub 2018 May 26.
Gastrointestinal nematode parasites are important pathogens of all domesticated livestock species. Fecal egg counts (FEC) are routinely used for evaluating anthelmintic efficacy and for making targeted anthelmintic treatment decisions. Numerous FEC techniques exist and vary in precision and accuracy. These performance characteristics are especially important when performing fecal egg count reduction tests (FECRT). The objective of this study was to compare the accuracy and precision of three commonly used FEC methods and determine if differences existed among livestock species. In this study, we evaluated the modified-Wisconsin, 3-chamber (high-sensitivity) McMaster, and Mini-FLOTAC methods in cattle, sheep, horses, and llamas in three phases. In the first phase, we performed an egg-spiking study to assess the egg recovery rate and accuracy of the different FEC methods. In the second phase, we examined clinical samples from four different livestock species and completed multiple replicate FEC using each method. In the last phase, we assessed the cheesecloth straining step as a potential source of egg loss. In the egg-spiking study, the Mini-FLOTAC recovered 70.9% of the eggs, which was significantly higher than either the McMaster (P = 0.002) or Wisconsin (P = 0.002). In the clinical samples from ruminants, Mini-FLOTAC consistently yielded the highest EPG, revealing a significantly higher level of egg recovery (P < 0.0001). For horses and llamas, both McMaster and Mini-FLOTAC yielded significantly higher EPG than Wisconsin (P < 0.0001, P < 0.0001, P < 0.001, and P = 0.024). Mini-FLOTAC was the most accurate method and was the most precise test for both species of ruminants. The Wisconsin method was the most precise for horses and McMaster was more precise for llama samples. We compared the Wisconsin and Mini-FLOTAC methods using a modified technique where both methods were performed using either the Mini-FLOTAC sieve or cheesecloth. The differences in the estimated mean EPG on log scale between the Wisconsin and mini-FLOTAC methods when cheesecloth was used (P < 0.0001) and when cheesecloth was excluded (P < 0.0001) were significant, providing strong evidence that the straining step is an important source of error. The high accuracy and precision demonstrated in this study for the Mini-FLOTAC, suggest that this method can be recommended for routine use in all host species. The benefits of Mini-FLOTAC will be especially relevant when high accuracy is important, such as when performing FECRT.
胃肠道线虫寄生虫是所有家养牲畜的重要病原体。粪便虫卵计数（FEC）通常用于评估驱虫效果以及做出针对性的驱虫治疗决策。存在多种FEC技术，其精度和准确性各不相同。在进行粪便虫卵计数减少试验（FECRT）时，这些性能特征尤为重要。本研究的目的是比较三种常用FEC方法的准确性和精度，并确定不同牲畜物种之间是否存在差异。在本研究中，我们分三个阶段对牛、羊、马和骆驼的改良威斯康星法、三室（高灵敏度）麦克马斯特法和Mini-FLOTAC法进行了评估。在第一阶段，我们进行了虫卵添加研究，以评估不同FEC方法的虫卵回收率和准确性。在第二阶段，我们检查了来自四种不同牲畜物种的临床样本，并使用每种方法完成了多次重复的FEC。在最后阶段，我们评估了粗棉布过滤步骤作为虫卵损失的潜在来源。在虫卵添加研究中，Mini-FLOTAC回收了70.9%的虫卵，显著高于麦克马斯特法（P = 0.002）或威斯康星法（P = 0.002）。在反刍动物的临床样本中，Mini-FLOTAC始终产生最高的每克粪便虫卵数（EPG），显示出显著更高的虫卵回收率（P < 0.0001）。对于马和骆驼，麦克马斯特法和Mini-FLOTAC产生的EPG均显著高于威斯康星法（P < 0.0001、P < 0.0001、P < 0.001和P = 0.024）。Mini-FLOTAC是最准确的方法，也是两种反刍动物物种中最精确的测试方法。威斯康星法对马最精确，麦克马斯特法对骆驼样本更精确。我们使用改良技术比较了威斯康星法和Mini-FLOTAC法，两种方法均使用Mini-FLOTAC筛网或粗棉布进行。使用粗棉布时（P < 0.0001）和不使用粗棉布时（P < 0.0001），威斯康星法和Mini-FLOTAC法在对数尺度上估计的平均EPG差异显著，有力地证明了过滤步骤是一个重要的误差来源。本研究中Mini-FLOTAC所展示的高准确性和精度表明，该方法可推荐用于所有宿主物种的常规使用。当高精度很重要时，如进行FECRT时，Mini-FLOTAC的优势将尤为明显。
