Norris Jamie K, Steuer Ashley E, Gravatte Holli S, Slusarewicz Paul, Bellaw Jennifer L, Scare Jessica A, Nielsen Martin K
M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, USA.
M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, USA.
Vet Parasitol. 2018 Aug 30;260:45-48. doi: 10.1016/j.vetpar.2018.08.004. Epub 2018 Aug 18.
Given the ever-increasing levels of anthelmintic resistance in livestock parasites globally, it is recommended to use parasite fecal egg counts to make treatment decisions and to evaluate treatment efficacy. The consensus in equine parasitology is to use a flotation medium with a specific gravity (SG) of ≥ 1.20 to float the main parasite egg types of interest in egg counting techniques. However, the density of common equine endoparasite eggs has been sparsely investigated. Equine tapeworm eggs are known to be particularly difficult to determine and count in fecal samples. It is unknown whether this could be because of differences in egg density. The aim of this study was to provide estimates of relative densities for equine ascarid, strongyle, and tapeworm eggs. Six aqueous glucose-salt solutions with specific gravities ranging from 1.06 to 1.16 were made and placed from most to least dense into thirteen 15 mL centrifuge tubes. Concentrated aqueous suspensions of the three types of endoparasite eggs were placed on top of each tube. These tubes were then centrifuged at 800 g for 20 min and each layer of flotation solution was carefully pipetted and transferred to a McMaster egg counting slide. Egg type and count were recorded for each specific gravity layer. Each egg was assigned a specific gravity based on the specific gravity layer it was observed in. In a second trial of this study, five similar flotation media were made ranging from 1.02 to 1.10 and were used in four subsequent replicates. In total between the two trials, the mean egg SGs of Anoplocephala perfoliata (n = 3811), Parascaris spp. (n = 3478), and strongylid type eggs (n = 9291) were 1.0636 (95% confidence interval (CI): 1.0629-1.0642), 1.0903 (95% CI: 1.0897-1.0909), and 1.0453 (95% CI: 1.0448-1.0458), respectively. The three egg types were statistically different from each other (p < 0.0001). This is the first time that the specific gravity of equine strongylid and Anoplocephala perfoliata eggs has been determined. With a tapeworm egg density demonstrated to be between that of strongylids and Parascaris spp., the poor recovery of tapeworm eggs in equine fecal samples must have other explanations.
鉴于全球家畜寄生虫的抗驱虫药水平不断提高，建议使用寄生虫粪便虫卵计数来做出治疗决策并评估治疗效果。马寄生虫学的共识是使用比重（SG）≥1.20的浮选介质来浮选虫卵计数技术中感兴趣的主要寄生虫卵类型。然而，常见马体内寄生虫卵的密度研究较少。已知马绦虫卵在粪便样本中特别难以确定和计数。尚不清楚这是否是由于卵密度的差异。本研究的目的是提供马蛔虫、圆线虫和绦虫卵相对密度的估计值。制备了六种比重范围为1.06至1.16的葡萄糖 - 盐水溶液，并按照密度从高到低的顺序放入13个15毫升离心管中。将三种类型的体内寄生虫卵的浓缩水悬浮液置于每个管的顶部。然后将这些管以800g离心20分钟，并小心地用移液管吸取每层浮选溶液并转移到麦克马斯特虫卵计数载玻片上。记录每个比重层的卵类型和数量。根据观察到每个卵所在的比重层为其指定一个比重。在本研究的第二次试验中，制备了五种比重范围为1.02至1.10的类似浮选介质，并在随后的四次重复中使用。在这两次试验中，叶状裸头绦虫（n = 3811）、副蛔虫属（n = 3478）和圆线虫类卵（n = 9291）的平均卵比重分别为1.0636（95%置信区间（CI）：1.0629 - 1.0642）、1.0903（95%CI：1.0897 - 1.0909）和1.0453（95%CI：1.0448 - 1.0458）。这三种卵类型在统计学上彼此不同（p < 0.0001）。这是首次确定马圆线虫和叶状裸头绦虫卵的比重。由于已证明绦虫卵密度介于圆线虫和副蛔虫属之间，马粪便样本中绦虫卵回收率低肯定有其他原因。
