A single diethylcarbamazine dose for treatment of Wuchereria bancrofti carriers in French Polynesia: efficacy and side effects.

In the fall of 1988, 14 Tahitian Wuchereria bancrofti carriers were treated by a single diethylcarbamazine (DEC) 3 mg/kg dose. Determination of blood microfilarial (mf) density was carried out on days 0, 7, 14, 30, 90 and 180 using the membrane filtration technique. Clinical signs and side effects were noted during the 3 days following treatment. Complete clearance of microfilaremia was observed in two carriers (negativation rate 14%). A decrease of mf density was noted in all of the 14 carriers, ranging from 35.2 to 99.2% (median 78.75%). The percentage decrease in mf density, determined for the whole group from the geometric mean of the 14 mf counts, was 86% by day 7 and reached 95% by day 180. Side effects were observed in 10 patients (71%) of whom 3 only were unable to perform usual activities for less than 24 hours. Though it induced an incomplete initial mf clearance, a single DEC 3 mg/kg dose was effective in reducing about 90% of the microfilaremia and in sustaining this reduction over a period of six months. Such long-term reduction (comparable to that observed in W. bancrofti carriers treated with a daily DEC 6 mg/kg dose during 12 days) is likely responsible for the consistent decrease of total mf counts observed in the Tahitian population which has been treated for years with single DEC doses given every six months.