Stewart T B, Fox M C, Wiles S E
Department of Veterinary Microbiology and Parasitology, School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803, USA.
Vet Parasitol. 1996 Nov 1;66(1-2):101-8. doi: 10.1016/s0304-4017(96)01001-1.
Four controlled trials with growing pigs were performed to determine efficacy of doramectin against natural and induced populations of nematodes. In Trial 1 (T1), 20 pigs with natural infections were assigned to one of two like groups on the basis of weight, sex and worm egg counts. In Trial 2 (T2), 20 pigs with negative worm egg counts were assigned to one of two groups on the basis of weight and sex. Each pig was subsequently given (per os) 3000 Trichuris suis embryonated eggs; 2000 Ascaris suum embryonated eggs; 10000 Oesophagostomum spp. infective larvae and 10,000 Strongyloides ransomi infective larvae (SC injection). In Trial 3 (T3), 20 pigs with negative worm egg counts were assigned as in T2, and each pig was subsequently given (per os) 2000 A. suum embryonated eggs, 15000 Oesophagostomum quadrispinulatum infective larvae, and 2891 Hyostrongylus rubidus infective larvae. In Trial 4 (T4), 16 pigs with negative worm egg counts were each assigned to one of two groups as in T2 and were given (per os) 2670 T. suis embryonated eggs. On Day 0 of each trial, each pig of the control group was injected IM in the neck with sterile saline at the rate of 1.5 ml 50 kg-1. Each pig in the treated group of each trial was similarly injected with doramectin at the rate of 300 micrograms kg-1. All pigs were necropsied 14 or 15 days post-treatment and parasites recovered by standard parasitological procedures. Efficacies against natural infections were: A. suum, 100%; Oesophagostomum spp. 100%; H. rubidus, 99.4%; and Strongyloides ransomi, 99.9%. Efficacies against induced infections were: 4th stage A. suum, 100%; 4th stage O.dentatum, 99.9%; 4th stage O.quadrispinulatum, 97.1 and 99.6%; 4th stage H. rubidus, 100%; adult S. ransomi, 100%; adult Trichuris suis in mixed infection, 54.1%; and in pure infection, 95.3%.
进行了四项针对生长猪的对照试验，以确定多拉菌素对自然感染和人工感染线虫群体的疗效。在试验1（T1）中，根据体重、性别和虫卵计数，将20头自然感染的猪分配到两个相似的组中。在试验2（T2）中，根据体重和性别，将20头虫卵计数为阴性的猪分配到两个组中。随后，每头猪经口给予3000枚猪鞭虫感染性虫卵、2000枚猪蛔虫感染性虫卵、10000枚结节虫属感染性幼虫和10000枚兰氏类圆线虫感染性幼虫（皮下注射）。在试验3（T3）中，同试验2一样将20头虫卵计数为阴性的猪进行分组，随后每头猪经口给予2000枚猪蛔虫感染性虫卵、15000枚四刺结节虫感染性幼虫和2891枚红色猪圆线虫感染性幼虫。在试验4（T4）中，同试验2一样将16头虫卵计数为阴性的猪分配到两个组中，并经口给予2670枚猪鞭虫感染性虫卵。在每项试验的第0天，对照组的每头猪颈部肌肉注射1.5 ml·50 kg-1的无菌生理盐水。每项试验治疗组的每头猪同样以300 μg·kg-1的剂量注射多拉菌素。所有猪在治疗后14或15天进行剖检，并通过标准寄生虫学程序回收寄生虫。对自然感染的疗效为：猪蛔虫100%、结节虫属100%、红色猪圆线虫99.4%、兰氏类圆线虫99.9%。对人工感染的疗效为：第4期猪蛔虫100%、第4期齿状结节虫99.9%、第4期四刺结节虫97.1%和99.6%、第4期红色猪圆线虫100%、成年兰氏类圆线虫100%、混合感染中的成年猪鞭虫54.1%、单纯感染中的成年猪鞭虫95.3%。
