Efficacy of mebendazole against Dictyocaulus arnfieldi in the donkey.

In a controlled trial in naturally infected donkeys the efficacy of mebendazole against Dictyocaulus arnfieldi infection was evaluated. A powder formulation of mebendazole given orally at a dosage rate of 4.3 to 5.7 mg per kg per day for five days had no apparent effect on existing lungworm burdens. However a paste formulation of mebendazole given orally at a higher dosage rate of 15.2 to 20.0 mg per kg per day for five days was 75 to 100 per cent effective in the removal of lungworms from individual animals.