[Ivermectin or diethylcarbamazine in spaced dosages in Bancroft's filariasis: which protocol?].

58 apparently healthy Polynesian Wuchereria bancrofti carriers were randomly allocated to 5 treatment groups: 1) two annual doses of ivermectin 100 mcg/kg, 2) three semi-annual doses of ivermectin 100 mcg/kg, 3) two annual doses of diethylcarbamazine (DEC) 3 mg/kg, 4) semi-annual doses of DEC 3 mg/kg, 5) two annual doses of DEC 6 mg/kg. Results observed during the 12-month period which followed last treatment have confirmed that efficacy of ivermectin is higher than that of DEC in terms of immediate clearance or complete negativation of microfilaremia, but not in terms of sustained reduction and that efficacy of repeated single doses of either DEC 3 mg/kg or ivermectin 100 mcg/kg is much higher when given semi-annually than annually. They also have indicated that (i) 6 months after last treatment: 3 semi-annual doses of 100 mcg/kg of ivermectin have resulted in high reduction of microfilaremia (85%) and, 2 annual doses of 6 mg/kg and 3 semi-annual doses of 3 mg/kg of DEC have resulted in even greater reduction (96 and 98% respectively) and (ii): 12 months after last treatment, the greatest reductions of microfilaremia (95 and 92%) have been observed in carriers treated, respectively, with 3 semi-annual doses of 3 mg/kg or with 2 annual doses of 6 mg/kg of DEC.(ABSTRACT TRUNCATED AT 250 WORDS)