Fritsche T, Kaufmann J, Pfister K
International Trypanotolerance Centre (ITC), Banjul, Gambia.
Vet Parasitol. 1993 Sep;49(2-4):271-83. doi: 10.1016/0304-4017(93)90126-8.
One hundred and four post mortem examinations of randomly selected sheep (52) and goats (52) were carried out weekly from March 1990 to February 1991. Gastrointestinal parasites were identified and counted. A large spectrum of 16 helminth species was found in 101 (97%) infected animals. The nematodes infecting small ruminants were, in order of predominance: Trichostrongylus colubriformis (96% of all animals), Oesophagostomum columbianum (82%), Haemonchus contortus (67%), Strongyloides papillosus (55%), Gaigeria pachyscelis (38%), Cooperia spp. (49%) and Trichuris ovis (12%). Forty-five (43%) necropsies revealed an infection with Moniezia benedeni, Avitellina centripunctata or Stilesia globulosa. Infections with Schistosoma bovis and Paramphistomum spp. were rarely seen. Goats carried significantly lower worm burdens than sheep and were less often infected by tapeworms. Nematode worm burdens followed a similar seasonal pattern in both host species. While Trichostrongylus colubriformis was also recovered in high numbers in the mid dry season, other species such as H. contortus, Strongyloides papillosus and Oesophagostomum columbianum reached distinct peaks in the rainy season (July-October). Different survival strategies for the prolonged dry season were observed. Haemonchus contortus outlived the unfavourable climatic conditions as inhibited larvae in the abomasal mucosa, while the other nematode species survived as adults with a reduced fecundity. Egg production per adult worm specimen was found to depend heavily on the season and egg counts in the dry season (November-June) did not correspond to the size of worm burdens. Unexpectedly high worm burdens were recovered from adult and old animals. Investigations of young animals indicated that no reinfection can occur during the dry season. The findings are discussed with regard to their relevance for strategic control of gastrointestinal nematodes in small ruminants.
1990年3月至1991年2月期间，每周对随机挑选的52只绵羊和52只山羊进行104次尸检。鉴定并计数胃肠道寄生虫。在101只（97%）受感染动物中发现了种类繁多的16种蠕虫。感染小型反刍动物的线虫，按优势顺序依次为：蛇形毛圆线虫（占所有动物的96%）、哥伦比亚食道口线虫（82%）、捻转血矛线虫（67%）、乳头类圆线虫（55%）、厚尾盖氏线虫（38%）、古柏属线虫（49%）和绵羊鞭虫（12%）。45次（43%）尸检显示感染了贝氏莫尼茨绦虫、点状无卵黄腺绦虫或球形斯氏绦虫。很少见到感染牛血吸虫和双腔吸虫属的情况。山羊体内的蠕虫负荷明显低于绵羊，感染绦虫的频率也较低。两种宿主物种中线虫的蠕虫负荷呈现相似的季节性模式。虽然在旱季中期也能大量检出蛇形毛圆线虫，但其他种类，如捻转血矛线虫、乳头类圆线虫和哥伦比亚食道口线虫在雨季（7月至10月）达到明显峰值。观察到了针对漫长旱季的不同生存策略。捻转血矛线虫以皱胃黏膜中的抑制性幼虫形式在不利气候条件下存活，而其他线虫物种则以繁殖力降低的成虫形式存活。发现每条成虫的产卵量在很大程度上取决于季节，旱季（11月至6月）的虫卵计数与蠕虫负荷大小不相符。从成年和老年动物中检出了意外高的蠕虫负荷。对幼龄动物的调查表明，旱季不会发生再感染。讨论了这些发现对小型反刍动物胃肠道线虫战略控制的相关性。
