Ivermectin and albendazole alone and in combination for the treatment of lymphatic filariasis in Ghana: follow-up after re-treatment with the combination

The efficacy of re-treatment with the combination of ivermectin (150-200 mug/kg bodyweight) and albendazole (400 mg) on Wuchereria bancrofti microfilaraemia was assessed in 1997-99 in 4 groups of individuals from coastal Ghana, which 1 year previously had received a primary treatment with placebo (n = 38), albendazole (n = 39), ivermectin (n = 34) or combination of albendazole and ivermectin (n = 42), respectively. One year after the re-treatment, an overall mean reduction in microfilarial intensity of 76.2% in relation to the intensity before re-treatment was observed, with no statistical significant difference between the 4 groups. The groups given primary treatment with placebo or the drug combination showed re-treatment reductions which were lower (72.5% and 69.8%, respectively) but not statistically significantly different from the reduction observed I year after the primary treatment with the combination (86.7%). The efficacy of the combination treatment thus appeared to be largely independent of the type of primary treatment given and multiplicative when used repeatedly.