Chemoprophylactic drug trials for treatment of dracunculiasis using the Dracunculus insignis-ferret model.

Groups of ferrets inoculated with Dracunculus insignis were treated with various anthelminthic compounds to evaluate the potential use of drugs in controlling the human parasite D. medinensis. The three primary compounds tested were diethylcarbamazine (DEC), albendazole (ALBZ), and invermectin (IVER); they were administered in dosages of 60 mg/kg, 10 mg/kg, and 1 mg/kg, respectively. Groups of animals received treatment either once at 60 days after inoculation, once at 60 and 90 days, or for 3 days at either 60 or 90 days postinoculation. The most marked decrease occurred in the animals that received treatment once at 60 and 90 days after inoculation. This was observed for all three drugs tested. Increased dosages, i.e., 3 days of treatment at 60 or 90 days did not result in decreased worm burdens. In no group was there a statistically significant reduction in worm burden when compared with controls. Two other compounds, metrifonate and CGP 6140, were tested in a more limited manner, but again the worm recovery rates were comparable with those in control groups. It would appear that existing drugs commonly used to treat helminthic infections are poor candidates for use in the campaign to eradicate guinea worm disease.