Mamman M, Williams D J, Murphy N B, Peregrine A S
International Laboratory for Research on Animal Diseases (ILRAD), Nairobi, Kenya.
Res Vet Sci. 1995 Mar;58(2):113-8. doi: 10.1016/0034-5288(95)90062-4.
Experiments were carried out in goats to determine the frequency with which diminazene-resistant trypanosomes occur in parasite populations before and after the intramuscular treatment of the goats with diminazene aceturate. Trypanosoma congolense IL 3274, a diminazene-resistant clone, was used to initiate infections in three groups of five goats. The goats in the first group were treated with diminazene aceturate at a dose of 7.0 mg kg-1 bodyweight within 10 seconds of infection; one of the goats was cured. All of the second group, which received no treatment, became parasitaemic. The third group of goats received the same dose of drug as the first group but three days after all of them were first detected parasitaemic; trypanosomes reappeared in all the five goats. When this third group was treated, the frequency of trypanosomes resistant to the drug dosage was estimated to be less than 1 in 10(3). The parasites which reappeared after the treatment of these animals were used to infect two additional groups of five goats intravenously. The goats in one group were treated with the same dose of drug as before, within 10 seconds of infection and were all cured. In contrast, the five goats in the second, untreated, group became parasitaemic. Finally, when the goats in which the infections had relapsed were retreated with diminazene aceturate at the same dose rate, the level of parasitaemia temporarily decreased by at least 10(3) trypanosomes ml-1. These findings suggest that diminazene-resistant T congolense occur at low levels in trypanosome populations despite attempts to select for a population resistant to the dose of drug used.
在山羊身上进行了实验，以确定在用乙酰氨基苯脒对山羊进行肌肉注射治疗之前和之后，抗双脒那锥虫在寄生虫群体中出现的频率。用抗双脒那克隆锥虫刚果锥虫IL 3274对三组五只山羊进行感染。第一组山羊在感染后10秒内以7.0毫克/千克体重的剂量接受乙酰氨基苯脒治疗；其中一只山羊被治愈。第二组未接受治疗，所有山羊都出现了寄生虫血症。第三组山羊在首次检测到寄生虫血症后三天接受与第一组相同剂量的药物治疗；五只山羊的锥虫均再次出现。当对第三组进行治疗时，对该药物剂量耐药的锥虫频率估计低于千分之一。这些动物治疗后再次出现的寄生虫被用于静脉感染另外两组五只山羊。一组山羊在感染后10秒内接受与之前相同剂量的药物治疗，全部治愈。相比之下，第二组未治疗的五只山羊出现了寄生虫血症。最后，当对感染复发的山羊以相同剂量率再次用乙酰氨基苯脒治疗时，寄生虫血症水平暂时降低了至少每毫升1000个锥虫。这些发现表明，尽管试图选择对所用药物剂量具有抗性的群体，但抗双脒那的刚果锥虫在锥虫群体中的水平较低。
