Fakae B B, Chiejina S N
Department of Veterinary Parasitology and Entomology, University of Nigeria, Nsukka.
Vet Parasitol. 1988 Apr;28(1-2):143-52. doi: 10.1016/0304-4017(88)90026-x.
The dynamics of pasture populations of infective larvae (L3) of Cooperia, Haemonchus and Trichostrongylus species were studied at Nsukka, eastern Nigeria, during April to November 1984. Six paddocks were contaminated artificially and one was contaminated naturally. Five of the paddocks, P1-P5, were sequentially contaminated with faeces of naturally infected cattle at approximately 4-6-weekly intervals. Paddocks P6 and P7 were repeatedly contaminated every 4-6 weeks artificially and by the naturally infected cattle, respectively. Larval development and survival occurred very readily during the wet season (April-October) but apparently ceased in November at the start of the dry season. Larval migration, however, occurred not only during the rains but also during the first 4 weeks of the dry season. Single contaminations during the rains quickly gave rise to single waves of infestation which also declined rapidly, in spite of the continuously favourable conditions for larval development and survival. The repeated contaminations produced three and four distinct and relatively short-lived larval peaks, respectively, with the first three peaks on both paddocks, namely the May, July and September/October peaks, being coincident. The four waves of herbage infestation on P7, which occurred at approximately 4-5 weekly intervals, were considered to have originated from four separate generations of the three trichostrongylids. However, Trichostrongylus sp. predominated in the first (May) peak while Cooperia and Haemonchus dominated the later peaks.
1984年4月至11月期间，在尼日利亚东部的恩苏卡对库柏属、血矛属和毛圆属线虫感染性幼虫（L3）的牧场种群动态进行了研究。六个围场被人工污染，一个被自然污染。其中五个围场，即P1 - P5，每隔约4 - 6周依次被自然感染牛的粪便污染。围场P6和P7分别每隔4 - 6周被人工和自然感染牛反复污染。幼虫的发育和存活在雨季（4月至10月）非常容易发生，但在11月旱季开始时显然停止。然而，幼虫迁移不仅发生在雨季，也发生在旱季的前4周。雨季的单次污染很快引发了单次感染浪潮，尽管幼虫发育和存活的条件一直有利，但感染浪潮也迅速下降。反复污染分别产生了三个和四个明显且相对短暂的幼虫高峰，两个围场的前三个高峰，即5月、7月和9月/10月的高峰是一致的。P7上大约每隔4 - 5周出现的四波牧草感染被认为源自三种毛圆科线虫的四代不同种群。然而，毛圆属线虫在第一个（5月）高峰中占主导地位，而库柏属和血矛属线虫在随后的高峰中占主导。
