Background

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.

Materials

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.

Results

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.

Conclusions

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.

中文翻译：

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结合分子和凝集素结合分析鉴定埃及绵羊和山羊粪便中的不同毛圆线虫卵

背景

毛圆线虫是全世界绵羊和山羊寄生性胃肠炎的常见原因。在属和/或种水平上准确识别这些线虫对于治疗选择和控制策略很重要。在本研究中，采用分子和卵-凝集素结合方法来鉴定埃及达卡利亚省六个地区绵羊和山羊群中循环的最具经济意义的毛圆线虫。

材料

收集了来自 17 个牛群中饲养的 653 和 205 只山羊的粪便样本，并使用改良的威斯康星蔗糖浮选法检测了毛圆线虫卵。为了鉴定存在的毛圆线虫，来自 75 个（63 只绵羊和 12 只山羊）具有高卵数 (EPG) 的样本的鸡蛋 和来自中等或低水平样本的混合鸡蛋（n = 19 个池，15 只绵羊和 4 只山羊）检查了 EPG。在单个 PCR 反应中，对六种不同的毛圆线虫的 rDNA 的 ITS2 区域进行了分子检测。对于鸡蛋-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Haemonchus contortus，Aleuria aurantia凝集素 (AAL) 用于毛圆线虫物种，扁豆凝集素（LCA），用于Teladorsagia circumcnicta和翅荚百脉根凝集素（LTL）的古柏物种。

结果

发现感染了 14 个 (82.3%) 的牛群，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线虫卵。PCR 和凝集素结合的结果一致，检测到 4种毛圆线虫：H. contortus、T. circlecincta、Trichostrongylus axei和Trichostrongylus colubriformis。在所有受感染的畜群中都发现了扭曲血球虫卵，并且分别在 21 和 5 份绵羊和山羊样本中作为单一物种发现。凝集素染色的涂片证明了扭曲旋毛虫卵比其他检测到的毛圆线虫卵的优势。发现 11 个牛群感染了T. axei作为第二大流行的毛圆线虫；然而，在阳性样本中发现很少有 AAL 染色的鸡蛋。混合感染经常被检测为H. contortus - T. axei组合。在来自两群羊的羊样本中发现了T. circlecincta感染，但在山羊的任何样本中都没有。没有奥斯特线虫leptospicularis，古柏curticei或线虫物种的测试样品中指出。

结论

这是第一次确定感染埃及绵羊和山羊的毛圆线虫的物种组成的分子和凝集素结合调查。Haemonchus contortus在埃及小反刍动物毛圆线虫病中起主要作用。鸡蛋凝集素染色作为一种快速而简单的技术在常规诊断中的应用前景广阔。

埃及早期报告的调查结果被制成表格并进行审查。