Chemoprophylaxis with diamfenetide against experimental infections of Fasciola hepatica in ruminants.

In limited trials against experimentally induced Fasciola hepatica infections, diamfenetide (N,N'-[oxybis(2,1-ethanediyloxy-4,1-phenylene)]bisacetamide) showed potential value for the prevention of acute fascioliasis in sheep and cattle. When given at a dosage of 10 mg/kg of body weight, diamfenetide was 87% effective in preventing establishment of F hepatica infections in sheep that were given the drug daily for 14 days, and was 96% effective in sheep that were given the drug for 21 days. Infective cysts (4 doses of 150 each) were given by capsule at 2-day intervals during the first week of medication. In additional trials, initial single large doses (40 to 100 mg/kg of body weight) given in conjunction with small doses each day (5 to 40 mg/kg), did not augment chemoprophylactic action. Signs of toxicosis attributable to diamfenetide were not observed. The severity of hepatic lesions ascribable to F hepatica correlated well with the degree of fluke control achieved. Small doses of diamfenetide given each day were less effective in calves than in sheep. Nevertheless, when given at dosages of 30 mg/kg daily for 11 days, the drug was 89% effective in preventing the development of F hepatica infections in two calves which were given infective cysts (4 X 100) by capsule at 2-day intervals during the first week of medication. Small doses of diamfenetide given daily were effective in preventing the establishment of F hepatica infections in ruminants.