Prichard R K
Institute of Parasitology, McGill University, Quebec, Canada.
Vet Parasitol. 1988 Feb;27(1-2):97-109. doi: 10.1016/0304-4017(88)90066-0.
Anthelmintic control of Ostertagia ostertagi in cattle presents some special problems because the arrested larval stage (hypobiotic EL4) tolerates all of the older anthelmintics. The only anthelmintics on the North American market that are effective against this stage as well as the adult and developing stages are ivermectin and fenbendazole. In addition to these, the newer broad-spectrum benzimidazoles and probenzimidazoles, albendazole, febantel, netobimin and oxfendazole, are effective and available in other countries. These anthelmintics can be used for prophylaxis of Type II ostertagiasis. The older anthelmintics, levamisole, morantel tartrate, thiabendazole, coumaphos, haloxon and phenothiazine, are effective against the adults and to some extent the developing stages of O. ostertagi so that they can be used to treat Type I ostertagiasis. They can also be used to prevent incoming larvae from establishing if they are administered continuously over a long period of time. This is possible with long term in-feed administration or by the use of the morantel slow release bolus. In cooler temperature regions, where cattle are housed over the winter, this bolus is given at turnout to remove any parasites in the animals and to kill incoming larvae for 60-90 days. This can prevent the build up of significant infective larvae on pasture so that very few arrested L4 larvae accumulate in the summer/autumn, effectively preventing Type II ostertagiasis from occurring later. The use of ivermectin and the newer benzimidazoles in intermittent or slow release devices should prove highly effective in the control of Type I and II ostertagiasis, as well as of subclinical ostertagiasis. To achieve maximum economic benefit, the use of anthelmintics should be based on sound epidemiological considerations, so that stock are not rapidly reinfected after treatment.
牛奥斯特他线虫的驱虫控制存在一些特殊问题，因为处于休眠状态的幼虫期（休眠性EL4）对所有旧的驱虫药都有耐受性。北美市场上唯一对该阶段以及成虫和发育阶段有效的驱虫药是伊维菌素和芬苯达唑。除此之外，新型广谱苯并咪唑类和丙硫苯咪唑类药物，如阿苯达唑、非班太尔、奈托比明和奥芬达唑，在其他国家是有效的且可获得的。这些驱虫药可用于预防II型奥斯特他线虫病。旧的驱虫药，如左旋咪唑、酒石酸噻嘧啶、噻苯达唑、蝇毒磷、氯羟吡啶和吩噻嗪，对奥斯特他线虫的成虫以及在一定程度上对发育阶段有效，因此可用于治疗I型奥斯特他线虫病。如果长期持续给药，它们还可用于防止进入的幼虫定殖。这可以通过长期在饲料中添加或使用噻嘧啶缓释丸来实现。在较寒冷的地区，牛在冬季圈养，在放牧时给予这种药丸可清除动物体内的任何寄生虫，并在60 - 90天内杀死进入的幼虫。这可以防止牧场上大量感染性幼虫的积累，从而在夏/秋季很少有休眠性L4幼虫积累，有效预防后期II型奥斯特他线虫病的发生。在间歇性或缓释装置中使用伊维菌素和新型苯并咪唑类药物在控制I型和II型奥斯特他线虫病以及亚临床奥斯特他线虫病方面应证明是非常有效的。为了实现最大的经济效益，驱虫药的使用应基于合理的流行病学考虑，以便动物在治疗后不会迅速再次感染。
