Nansen P, Midtgaard N
Nord Vet Med. 1977 Jun;29(6):257-62.
The frequency of fascioliasis in sheep of south-western Jutland has been determined on the basis of slaughterhouse registration of infected livers over a 5-year period (1969-1973). The average yearly percentage of adult sheep found to be infected ranged from 83.9 to 91.2%, whereas less than 1 % of the slaughtered lambs proved infected. The high infection percentage among adult animals and the strikingly low frequency among slaughter lambs could be explained by the characteristic management system of the marshland: In summer the sheep graze the dike and the foreland on its seaward side, and in winter the animals graze in the marshland. Lymnaea truncatula is not found on or at the seaward side of the dike, whereas it is abundant all over the marshland. Thus the lambs graze exclusively the snail-free area from which they are taken directly to the slaughterhouse. The summer grazing also protects the adult animals as they avoid the massive uptake of metacercariae which normally takes place in fluke infected areas in late summer.
基于对1969年至1973年这5年间屠宰场感染肝脏的登记记录，已确定了日德兰半岛西南部绵羊的肝片吸虫病感染率。被发现感染的成年绵羊的年平均百分比在83.9%至91.2%之间，而被屠宰的羔羊中感染率不到1%。成年动物的高感染率以及屠宰羔羊中极低的感染频率可以通过沼泽地特有的管理系统来解释：夏季绵羊在堤坝及其向海一侧的前滩放牧，冬季则在沼泽地放牧。截口椎实螺在堤坝上或向海一侧未被发现，而在整个沼泽地都很常见。因此，羔羊只在无螺区域放牧，然后直接被送往屠宰场。夏季放牧也保护了成年动物，因为它们避免了通常在夏末吸虫感染地区大量摄取囊蚴的情况。
