Efficacy of albendazole for prevention of fascioliasis in sheep.

Daily doses of albendazole administered as a premix in the feed for 35 days were effective in preventing Fasciola hepatica infections in 17 sheep in three groups: 5 mg/kg/day (6 sheep) was 100% effective; 3 mg/kg/day (5 sheep) was 98% effective; and 1 mg/kg/day (6 sheep) was 42% effective. Infective cysts were given daily for 5 days during the first week of treatment, treatment was continued an additional 28 days, and sheep were necropsied 14 weeks after final cyst inoculation. There were no visible lesions in any livers of sheep given albendazole at the rate of 5 mg/kg/day or in three of five livers of sheep dosed at the rate of 3 mg/kg/day. Sheep treated with albendazole had a mean weight gain of 2.7 kg, 4.0 kg, and 4.0 kg greater than the controls for the dosages of 1, 3, and 5 mg/kg/day, respectively. Determination of bile duct damage by measurement of serum gamma-glutamyl transpeptidase activity at 9 weeks after final cyst inoculation revealed increases of 3.0X, 1.0X, and 1.1X for the dosages of 1, 3, and 5 mg/kg/day, respectively, and 2.3X for the control, as compared with 7 weeks after final cyst inoculation.