Jacquiet P, Humbert J F, Comes A M, Cabaret J, Thiam A, Cheikh D
Centre National d'Elevage et de Recherches Vétérinaires, Nouakchott, République Islamique de Mauritanie.
Parasitology. 1995 May;110 ( Pt 4):483-92. doi: 10.1017/s0031182000064829.
The 4 species of ruminants (dromedary, zebu cattle, sheep and goat) in arid areas of Mauritania harboured Haemonchus spp. as the most frequent internal parasite. This was a rare situation where the 3 putative species, H. longistipes (dromedary), H. placei (zebu cattle) and H. contortus (sheep and goat) occurred sympatrically. The study was undertaken on hosts slaughtered at the Nouakchott abattoir, on the basis of monthly collection of worms. The environment was very unfavourable to H. placei and unfavourable to H. contortus, as intensity of infection remained low throughout the year, whereas infection in the dromedary was 10 to 20-fold higher. The survival strategies during the long, dry season were different: the surviving stages were either 4th-stage larvae in digesta (dromedaries), 4th-stage larvae either in digesta or mucosae (cattle), or 4th-stage larvae in mucosae and few adults (sheep and goats). The prolificacy of female worms, indicative of the potential to contaminate pastures, was similar for all Haemonchus spp. in the rainy season. H. longistipes behave differently during the pre-rainy season as no increase of prolificacy could be demonstrated as observed in the other species. Traits of vulvar morphology are considered as markers of ecological adaptation and were studied. The knobbed and smooth female morphs (in equal proportions) were the most frequent in H. longistipes, the knobbed morph out-numbered the other morphs in H. placei, and all 3 morphs were present in sheep and goats with the linguiform form being predominant. Genetic characterization of the 3 species was performed by means of Random Amplified Polymorphic DNA (RAPD). Three groups were obtained from analysis of these data: 1 group with individuals of H. contortus, 1 group with individuals of H. placei, and 1 group with individuals of H. longistipes. This indicated that, although the 3 species were valid, H. contortus and H. placei were more similar. Intraspecific variability was 2-fold higher in H. contortus than in the 2 other species. The ecological, morphological and genetical studies showed that H. longistipes, H. placei and H. contortus could be arranged in increasing order of variability.
毛里塔尼亚干旱地区的4种反刍动物（单峰骆驼、瘤牛、绵羊和山羊）体内，血矛线虫属是最常见的体内寄生虫。在这种罕见的情况下，3种假定的血矛线虫——长柄血矛线虫（单峰骆驼）、柏氏血矛线虫（瘤牛）和捻转血矛线虫（绵羊和山羊）在同一地区共存。该研究以努瓦克肖特屠宰场宰杀的宿主为对象，基于每月收集的蠕虫样本展开。该环境对柏氏血矛线虫非常不利，对捻转血矛线虫也不利，因为全年感染强度都很低，而单峰骆驼的感染率要高10到20倍。在漫长的旱季，它们的生存策略各不相同：存活阶段有的是消化道内的第四期幼虫（单峰骆驼），有的是消化道或黏膜内的第四期幼虫（牛），还有的是黏膜内的第四期幼虫和少量成虫（绵羊和山羊）。雨季时，所有血矛线虫属雌性蠕虫的繁殖力相似，这表明它们污染牧场的潜力相当。长柄血矛线虫在雨季前的表现有所不同，因为未观察到其繁殖力像其他物种那样有所增加。外阴形态特征被视为生态适应性的标志并进行了研究。长柄血矛线虫中，有瘤和光滑的雌性形态（比例相同）最为常见；柏氏血矛线虫中，有瘤形态的数量超过其他形态；绵羊和山羊体内的3种形态都有，且舌状形态占主导。通过随机扩增多态性DNA（RAPD）技术对这3个物种进行了基因特征分析。分析这些数据后得到3组：一组是捻转血矛线虫个体，一组是柏氏血矛线虫个体，一组是长柄血矛线虫个体。这表明，虽然这3个物种是有效的，但捻转血矛线虫和柏氏血矛线虫更为相似。捻转血矛线虫的种内变异性比其他两个物种高2倍。生态、形态和基因研究表明，长柄血矛线虫、柏氏血矛线虫和捻转血矛线虫的变异性呈递增顺序排列。
