Eljaki A A, Al Kappany Y M, Grosz D D, Smart A J, Hildreth M B
Departments of Biology & Microbiology and Veterinary & Biomedical Sciences, South Dakota State University, Brookings, SD 57007, United States; Departments of Zoology, University of Omar Almukhtar, Al Bayda, Libya and University of Benghazi, Benghazi, Libya.
Departments of Biology & Microbiology and Veterinary & Biomedical Sciences, South Dakota State University, Brookings, SD 57007, United States; Department of Parasitology. Faculty of Veterinary Medicine, Mansoura University, Mansoura, Dakahlia Governorate 35516, Egypt.
Vet Parasitol. 2016 Aug 30;227:48-55. doi: 10.1016/j.vetpar.2016.07.022. Epub 2016 Jul 20.
North American bison (Bison bison) producers face many challenges, including the potential clinical and economics problems caused by trichostrongyle nematodes within their herds. Little is known about the prevalence, intensity, geographical distribution and clinical significance of these parasites in commercial bison herds, even from regions where bison production has become popular. This study involved a large herd of bison from eastern South Dakota that was experiencing clinical parasitism due to a temporary over-stocking problem. After documenting fecal egg counts (FECs) and trichostrongyle genera present among the 3 main age-categories (i.e. adults, yearlings, calves) of bison during this heavily infected grazing season, the effects of doramectin treatment on the different age groups was also evaluated. This is the first bison study using PCR to identify genera of trichostrongyles in fecal samples. Virtually all 103 bison fecal samples from all 3 age classes were shedding trichostrongyle eggs by the end of the season, and the mean FECs were 34 eggs/g (EPG) among the cows, 125 EPG in the yearlings, and 186 EGP among calves. Based upon this heavily-infected herd, there is evidence that the susceptibility of bison to trichostrongyles is more similar to beef cattle than to sheep. Other parasites such as Moniezia, Nematodirus, Trichuris, and coccidians were also identified in these samples. All but 3 of the 51 samples analyzed with PCR shown at least 1 trichostrongyle genera. Ostertagia was detected in 68.6% of the samples, Cooperia in 80.39%, Haemonchus in at least 73% and Trichostrongylus in 16% of the herd. Most commonly, bison were infected with combinations of Haemonchus/Ostertagia/Cooperia. After treatment with doramectin, the mean FECs dropped by 99.9% for all of the bison age classes.
北美野牛（美洲野牛）养殖户面临诸多挑战，包括其牛群中毛圆线虫引发的潜在临床和经济问题。即便在野牛养殖盛行的地区，对于这些寄生虫在商业野牛群中的流行率、感染强度、地理分布及临床意义，人们了解甚少。本研究涉及南达科他州东部的一大群野牛，由于临时过度放牧问题，这群野牛正遭受临床寄生虫感染。在记录了这个重度感染放牧季节中野牛三个主要年龄组（即成年牛、一岁小牛、犊牛）的粪便虫卵计数（FEC）以及存在的毛圆线虫属之后，还评估了多拉菌素治疗对不同年龄组的影响。这是第一项利用聚合酶链反应（PCR）鉴定粪便样本中毛圆线虫属的野牛研究。到季节结束时，几乎所有来自三个年龄组的103份野牛粪便样本都在排出毛圆线虫卵，母牛的平均FEC为34个卵/克（EPG），一岁小牛为125 EPG，犊牛为186 EGP。基于这个重度感染的牛群，有证据表明野牛对毛圆线虫的易感性与肉牛更为相似，而非绵羊。这些样本中还鉴定出了其他寄生虫，如莫尼茨绦虫、细颈线虫、毛首线虫和球虫。在51份用PCR分析的样本中，除3份外，其余样本均显示至少有1种毛圆线虫属。在68.6%的样本中检测到奥斯特他线虫，80.39%的样本中检测到古柏线虫，至少73%的样本中检测到血矛线虫，16%的牛群中检测到毛圆线虫。最常见的情况是，野牛感染血矛线虫/奥斯特他线虫/古柏线虫的组合。用多拉菌素治疗后，所有野牛年龄组的平均FEC下降了99.9%。
