Jansen J
Vet Q. 1987 Apr;9(2):97-102. doi: 10.1080/01652176.1987.9694085.
The trichostrongylid and strongylid egg output in a group of ewes lambing in March, the middle of the usual lambing time in the Netherlands, was compared with counts in groups of older ewes and yearling ewes lambing in May-June and with counts in a group of barren ewes. The groups lambing in March showed only a rise related to parturition date as normally seen in the Netherlands. A few of the late lambing ewes showed a slight rise in spring, but all of them showed a peri-parturient rise related to parturition date. In the late lambing ewes and in the barren ewes egg counts due to reinfection were seen in summer. It is concluded that under the present circumstances a true spring rise, the calendar phenomenon, occurs very irregularly, while a peri-parturient rise related to the parturition date is a common phenomenon. The occurence of high egg counts in summer, excluding consideration on the barren ewes, in the late lambing ewes only, suggests that changing the traditional husbandry system may influence the epidemiological pattern of the trichostrongylid infections.
在荷兰通常产羔时间的中期即3月产羔的一组母羊中，将毛圆线虫和圆线虫的产卵量与5 - 6月产羔的成年母羊组和周岁母羊组的计数进行比较，并与一组不产羔母羊的计数进行比较。3月产羔的母羊组仅出现了荷兰常见的与产羔日期相关的上升。一些晚产母羊在春季有轻微上升，但它们都出现了与产羔日期相关的围产期上升。在晚产母羊和不产羔母羊中，夏季出现了再感染导致的虫卵计数。得出的结论是，在目前情况下，真正的春季上升，即日历现象，非常不规律地出现，而与产羔日期相关的围产期上升是一种常见现象。仅在晚产母羊中夏季出现高虫卵计数（不考虑不产羔母羊），这表明改变传统养殖系统可能会影响毛圆线虫感染的流行病学模式。
