Svensson C, Olofsson H, Uggla A
Swedish University of Agricultural Sciences, Skara, Sweden.
Appl Parasitol. 1996 Sep;37(3):209-16.
Twelve calves which had been immunised with a trickle dose of altogether 100,000 oocysts of Eimeria alabamensis 16 days before turnout and 12 uninoculated calves were monitored during their first 20 days of grazing on a pasture naturally contaminated with oocysts of E. alabamensis. Eleven of the uninoculated calves developed gruel-like diarrhoea 3-6 days after turnout and excreted more than 850,000 oocysts/g of faeces (OPG) a few days later. In contrast, none of the immunised calves developed clinical coccidiosis and most of them excreted only a few oocysts. They lost on average 18 kg less in bodyweight than the unimmunised control calves. On day 21 all the calves were rehoused and on day 27 they were challenged with 10 million sporulated oocysts of E. alabamensis and turned out onto the same pasture. Only insignificant clinical signs were observed in 2 of the immunised calves and in one of the control calves. It was concluded that immunisation is a promising control measure for E. alabamensis coccidiosis. However, fewer or attenuated oocysts must be used, as 9 of the 12 inoculated calves developed clinical coccidiosis before turnout as a result of the immunisation doses.
12头犊牛在放牧前16天接受了总共100,000个阿拉巴马艾美耳球虫卵囊的微量接种，12头未接种的犊牛在天然被阿拉巴马艾美耳球虫卵囊污染的牧场上放牧的前20天受到监测。11头未接种的犊牛在放牧后3 - 6天出现稀粥样腹泻，几天后每克粪便中排出超过850,000个卵囊（OPG）。相比之下，接种过的犊牛均未发生临床球虫病，且大多数仅排出少量卵囊。它们的体重平均比未接种的对照犊牛少损失18千克。在第21天，所有犊牛被重新圈养，在第27天，它们用1000万个阿拉巴马艾美耳球虫的孢子化卵囊进行攻毒，并被放回同一牧场。在接种过的2头犊牛和1头对照犊牛中仅观察到不明显的临床症状。得出的结论是，免疫接种是控制阿拉巴马艾美耳球虫病的一种有前景的措施。然而，必须使用更少或减毒的卵囊，因为12头接种的犊牛中有9头由于免疫接种剂量在放牧前就出现了临床球虫病。
