Gulland F M
Large Animal Research Group, Department of Zoology, University of Cambridge.
Parasitology. 1992 Dec;105 ( Pt 3):493-503. doi: 10.1017/s0031182000074679.
In early 1989, two-thirds of the Soay sheep population on St Kilda died over 12 weeks. Post-mortem examinations revealed emaciated carcasses and considerable nematode burdens, with protein-energy malnutrition as the probable cause of death. Haematological and blood biochemical changes in the sheep, as well as fecundity of gastrointestinal nematodes, suggested the hosts were immunosuppressed. In parallel, laboratory experiments in which Soay sheep on a high plane of nutrition were artificially infected with Ostertagia circumcincta, showed no clinical signs or mortality when supporting worm burdens similar to those recorded in dead sheep on St Kilda. Anthelmintic treatment of a group of animals increased daily survival rates in ewes and male lambs, although treated animals became re-infected as the 'crash' progressed. It is suggested that parasites contribute to mortality in malnourished hosts, exacerbating the effects of food shortage.
1989年初，圣基尔达岛上三分之二的索艾羊在12周内死亡。尸检显示羊尸体消瘦且体内有大量线虫，蛋白质 - 能量营养不良可能是死亡原因。羊的血液学和血液生化变化以及胃肠线虫的繁殖力表明宿主免疫受到抑制。与此同时，在实验室实验中，营养水平高的索艾羊被人工感染环纹奥斯特线虫，当体内蠕虫负荷与圣基尔达岛上死亡羊只记录的负荷相似时，未出现临床症状或死亡情况。一组动物进行驱虫治疗后，母羊和雄性羔羊的日存活率提高，不过随着“羊群数量骤减”的进展，接受治疗的动物再次被感染。研究表明，寄生虫会导致营养不良宿主死亡，加剧食物短缺的影响。
