Ogunsusi R A, Eysker M
Res Vet Sci. 1979 Jan;26(1):108-10.
Worm counts from Yankassa ewes, lambs and tracer lambs grazing unimproved pasture at Zaria were obtained each month during the rainy season of 1976. In June and July up to 14 per cent of the Haemonchus contortus populations consisted of early fourth stage larvae (L4). In August this increased to more than 55 per cent and in October to more than 95 per cent. From June to August most of the abundant late L4 contained rodlike crystals. More than 95 per cent of the Haemonchus contortus populations of two lambs killed two weeks after infection with infective larvae, cultured for seven days at 25 degrees to 30 degrees C in the dark, were early L4. Inhibited 3rd stage Trichostrongylus spp did not exceed 26 per cent of the worm populations.
1976年雨季期间，每月都对在扎里亚未改良牧场上放牧的扬卡萨母羊、羔羊和追踪羔羊进行蠕虫计数。6月和7月，捻转血矛线虫种群中多达14%为早期第四阶段幼虫（L4）。8月，这一比例增至55%以上，10月则超过95%。6月至8月，大多数数量众多的晚期L4含有棒状晶体。两只羔羊在感染感染性幼虫两周后被宰杀，在黑暗中于25摄氏度至30摄氏度培养7天，其捻转血矛线虫种群中超过95%为早期L4。受抑制的第三阶段毛圆线虫属不超过蠕虫种群的26%。
