Parasitology Department, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt.
Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, USA.
Acta Parasitol. 2021 Jun;66(2):384-396. doi: 10.1007/s11686-020-00287-y. Epub 2020 Oct 9.
Trichostrongyles are common causes of parasitic gastroenteritis in sheep and goats worldwide. Accurate identification of these nematodes to the genus and/or species level is important for therapy selection and control strategies. In the present study, molecular and egg-lectin binding approaches were employed to identify the most economically important trichostrongyles circulating in sheep and goat herds from six districts in Dakahlia governorate, Egypt.
Fecal samples from 653 and 205 goats reared within 17 herds were collected and tested for the trichostrongyle eggs using the modified Wisconsin sucrose flotation method. For identification of the trichostrongyle(s) present, eggs from 75 (63 sheep and 12 goats) samples which had high egg count (EPG) and pooled eggs (n = 19 pools, 15 sheep and 4 goats) from samples with moderate or low EPGs were examined. Molecular examination was conducted amplifying the ITS2 region of the rDNA for six different trichostrongyles in individual PCR reactions. For egg-lectin bindings, 4 fluorescently-labeled specific lectins were used; peanut agglutinin (PNA) for Haemonchus contortus, Aleuria aurantia agglutinin (AAL) for Trichostrongylus species, Lens culinaris agglutinin (LCA) for Teladorsagia circumcnicta and Lotus tetragonolobus lectin (LTL) for Cooperia species.
Fourteen (82.3%) herds were found infected, of which trichostrongyle eggs were detected in fecal samples of 26.5% (173/653) of sheep and 10.2% (21/205) of goats. Results of the PCR and lectin bindings were compatible and 4 trichostrongyles were detected: H. contortus, T. circumcincta, Trichostrongylus axei and Trichostrongylus colubriformis. Haemonchus contortus eggs were found in all the infected herds, and as the single species in 21 and 5 of sheep and goat samples, respectively. Lectin stained smears demonstrated the dominance of H. contortus eggs over eggs of the other detected trichostrongyles. Eleven herds were found infected with T. axei as the second most prevalent trichostrongyle; however, few AAL-stained eggs were noticed in the positive samples. Mixed infections were frequently detected as H. contortus-T. axei combination. Infections with T. circumcincta were noted in sheep samples from two herds, but not in any sample from the goats. No Ostertagia leptospicularis, Cooperia curticei or Nematodirus species were noted among the tested samples.
This is the first molecular and lectin binding survey to determine the species composition of trichostrongyles infecting sheep and goats from Egypt. Haemonchus contortus plays the principal role in small ruminant trichostrongylosis in Egypt. Egg-lectin staining shows promise for future for its application in routine diagnosis as a rapid and simple technique. Findings of the earlier reports from Egypt are tabulated and reviewed.
在全球范围内，毛圆科线虫是绵羊和山羊寄生性肠胃炎的常见原因。准确鉴定这些线虫到属和/或种的水平对于治疗选择和控制策略非常重要。在本研究中，采用分子和卵-凝集素结合方法来鉴定来自埃及达卡利亚省六个地区的绵羊和山羊群中循环的最具经济重要性的毛圆科线虫。
采集了来自 17 个羊群的 653 只绵羊和 205 只山羊的粪便样本，并使用改良的威斯康星蔗糖漂浮法检测了毛圆科线虫卵。为了鉴定存在的毛圆科线虫，对高卵计数（EPG）的 75 个样本的卵（来自 63 只绵羊和 12 只山羊）和低或中 EPG 的样本的混合卵（n = 19 个样本，来自 15 只绵羊和 4 只山羊）进行了检查。分子检测是通过在个体 PCR 反应中扩增 rDNA 的 ITS2 区域进行的。对于卵-凝集素结合，使用了 4 种荧光标记的特异性凝集素；花生凝集素（PNA）用于捻转血矛线虫，Aleuria aurantia 凝集素（AAL）用于毛圆科线虫，扁豆凝集素（LCA）用于泰泽氏绦虫和 Lotus tetragonolobus 凝集素（LTL）用于结肠小袋纤毛虫。
发现 14 个（82.3%）羊群受到感染，其中在 26.5%（173/653）的绵羊和 10.2%（21/205）的山羊粪便样本中检测到毛圆科线虫卵。PCR 和凝集素结合的结果是一致的，共检测到 4 种毛圆科线虫：捻转血矛线虫、泰泽氏绦虫、弯口毛圆线虫和Colubriformis 毛圆线虫。捻转血矛线虫卵在所有感染的羊群中都有发现，在绵羊和山羊样本中分别作为单一物种存在于 21 和 5 个样本中。凝集素染色涂片显示捻转血矛线虫卵比其他检测到的毛圆科线虫卵更占优势。11 个羊群被发现感染了弯口毛圆线虫，是第二大常见的毛圆科线虫；然而，在阳性样本中只注意到了少量的 AAL 染色卵。混合感染经常被检测到，如捻转血矛线虫-弯口毛圆线虫的组合。在两个羊群的绵羊样本中发现了泰泽氏绦虫感染，但在任何山羊样本中均未发现。在检测的样本中未发现奥斯特拉线虫、库蒂斯绦虫或线虫属。
这是首次采用分子和凝集素结合技术来确定感染埃及绵羊和山羊的毛圆科线虫的种组成。捻转血矛线虫在埃及的小反刍动物毛圆线虫病中起主要作用。卵-凝集素染色显示出在常规诊断中应用的前景，因为它是一种快速简单的技术。埃及以前的报告结果也进行了列表示并进行了综述。
