四种抗寄生原虫药物对伊氏锥虫、马媾疫锥虫和布氏锥虫感染的治疗作用

目的研究分析伊氏锥虫(Trypanosomaevansi)、马媾疫锥虫(T.equiperdum)和布氏锥虫指名亚种(T.b.brucei)对四种抗寄生原虫药物(氯喹、甲硝唑、MelCy和贝尼尔)抗性的差异,及药物剂量和治疗时间对治疗效果的影响。方法将105锥虫经腹腔接种小鼠,感染后于不同时间用不同剂量的药物对小鼠进行治疗,观察小鼠虫血症的变化和死亡情况。结果氯喹和甲硝唑在单用或合用时对这3种锥虫没有可见的疗效,MelCy与贝尼尔则具有良好的治疗效果;其中1.6mg/kg的MelCy对3种锥虫都有完全的治愈作用;贝尼尔在7mg/kg的剂量水平对马媾疫锥虫和布氏锥虫也有完全的杀灭作用。马媾疫锥虫和布氏锥虫对贝尼尔敏感,但伊氏锥虫对贝尼尔则表现出明显的抗药性。提高药物的注射剂量或在感染早期治疗可以延长感染小鼠的存活时间。结论伊氏锥虫对所用药物的抗性最强,其次为布氏锥虫指名亚种,马媾疫锥虫对药物最敏感。加大药物注射剂量和感染后及早治疗可提高治愈率。

Comparison of the Therapeutic Effects of Four Antiparasitic Protozoan Drugs on Trypanosoma evansi, T. equiperdum and T. b.brucei in Mice

Objective To evaluate the effect of chloroquine,metronidazole,Mel Cy and Berenil on treating Trypanosoma evansi(STIB 806),T.equiperdum(STIB 818) and T.b.brucei(STIB 920) infection in mice.Method 105 trypanosomes of Trypanosoma evansi(STIB 806),T.equiperdum(STIB 818) and T.b.brucei(STIB 920) were intraperitoneally inoculated into mice.Infected mice were treated with chloroquine,metronidazole,Mel Cy or Berenil with different dosages and at different time of post-infection.The parasitemia and the time of death of the infected mice were evaluated.Result Chloroquine,metronidazole alone or mixture of both showed no effect on treating of trypanosomes infection,while Mel Cy and Berenil could effectively treat trypanosomes infection.Mel Cy at a dosage of 1.6 mg/kg body weight was found to completely cure the mice infected with these three trypanosome species,while Berenil at a dosage of 7 mg/kg body weight could also cure the mice infected with T.equiperdum and T.b.brucei.T.evansi was more resistance to Berenil than T.equiperdum and T.b.brucei.Infected mice treated at early stage of post-infection or with higher dosage could survive longer than those treated with lower dosage or at late stage.Conclusion T.evansi is the strongest drug-resistance species and T.b.brucei is moderate resistance species,while T.equiperdum is the most sensitive species to the tested compounds.Higher dosage or early treatment can help to cure the trypanosomiasis caused by these species in mice.