Villacorta I, Peeters J E, Vanopdenbosch E, Ares-Mazás E, Theys H
National Institute of Veterinary Research, Brussels, Belgium.
Antimicrob Agents Chemother. 1991 Feb;35(2):283-7. doi: 10.1128/AAC.35.2.283.
The efficacy of halofuginone lactate against natural Cryptosporidium parvum infection in 150 neonatal market calves of a mixed Belgian breed was tested. The drug was administered orally in the milk replacer over a period of 3 to 14 days at doses ranging from 30 to 500 micrograms/kg of body weight. Over a period of 4 weeks, the animals were examined twice a week for shedding of C. parvum oocysts and were scored semiquantitatively for diarrhea. Weight gain was assessed after 2 and 4 weeks. Subclinical infections by rota-, corona-, and bovine picobirnaviruses were equally distributed in the different groups. In total, 93% of the unmedicated calves eliminated C. parvum within 10 days after arrival at the rearing unit and 62% of them showed diarrhea. Immediately after treatment with halofuginone was started, no more signs of Cryptosporidium-associated diarrhea were established. From the level of 60 micrograms/kg on, oocysts were no longer detected in 98% of animals 5 to 6 days after the start of treatment. Animals remained negative for at least 7 days after withdrawal of the drug. From 7 to 10 days after withdrawal, some animals excreted oocysts again. The number of shedders was closely linked with increasing doses of the drug, which indicates that lower doses do not interrupt infection completely and allow development of immunity. In this respect, a dose of 60 to 125 micrograms/kg over a period of 7 days seems most appropriate in practice. Toxic side effects were noticed only at 500 micrograms/kg.
对150头比利时混合品种的新生市场犊牛进行了乳酸卤夫酮抗自然感染微小隐孢子虫的疗效测试。该药物在代乳品中口服给药，持续3至14天，剂量范围为30至500微克/千克体重。在4周的时间里，每周对动物检查两次微小隐孢子虫卵囊的排出情况，并对腹泻进行半定量评分。在2周和4周后评估体重增加情况。轮状病毒、冠状病毒和牛微小双RNA病毒的亚临床感染在不同组中分布均匀。总共，93%的未用药犊牛在到达饲养单位后10天内清除了微小隐孢子虫，其中62%出现腹泻。开始用卤夫酮治疗后，立即不再有与隐孢子虫相关的腹泻迹象。从60微克/千克的剂量开始，在治疗开始后5至6天，98%的动物不再检测到卵囊。停药后动物至少7天保持阴性。停药后7至10天，一些动物再次排出卵囊。排虫数量与药物剂量增加密切相关，这表明较低剂量不能完全中断感染，且允许免疫力发展。在这方面，在7天内给予60至125微克/千克的剂量在实践中似乎最合适。仅在500微克/千克时观察到毒性副作用。
