[Fenbendazole therapy of experimental larval echinococcosis. I. The effect of fenbendazole on worm burden and protoscolex development of Echinococcus multilocularis (author's transl)].

Application of fenbendazole (methyl-5-(phenyl-thio)-benzimidazole-2-carbamate) in Echinococcus multilocularis infected mice showed a significant efficiency on the development of the cysts; the worm burden and the number of protoscolices were significantly reduced in the treated animals in comparison with the non-treated control mice. The degree of efficiency was subject to the way of application, the duration of medication, and the parasite strain: 1. On application of f. as medicated feed (500 ppm) worm burden and protoscolex number were reduced the most an average parasite weight of 105 mg and 2 protoscolices against 1942 mg and 99 protoscolices. Treatment by oral application with emulsion of 2.5% (1 ml/mouse/day, 5 x per week over a period of 2--5.5 months) the efficiency was less expressed (845 mg, 53 protoscolices). 2. By extending the treatment from 60 to 102 and 165 days resp. the reduction of worm burden can be increased from 81 to 95%. 3. From 2 parasite strains one which was recently isolated from a fox, reacted more on the treatment than the other one: 85 mg parasite weight against 1218 mg in the nontreated controls. On the other strain continued since about 25 years by intraperitoneal inoculation, the efficiency was more reduced: The worm burden was 866 against 2666 mg in the control mice.