Prevention of acute adenolymphangitis in brugian filariasis: comparison of the efficacy of ivermectin and diethylcarbamazine, each combined with local treatment of the affected limb.

Acute attacks of adenolymphangitis (ADL) not only force patients with lymphatic filariasis to seek medical attention but also hasten the progression of filarial oedema. Patients with filariasis-associated ADL are currently treated with repeated courses of the antifilarial drug diethylcarbamazine (DEC), with or without antibiotics and anti-inflammatory agents. In this double-blind, placebo-controlled study, the efficacy of local treatment of the affected limb combined with repeated doses of ivermectin or DEC, in preventing the occurrence of ADL in Brugia malayi lymphatic filariasis, was examined. Overall, 120 patients who had each had at least two ADL attacks in the previous year were each admitted to the study at the time of an ongoing episode of ADL. The patients were randomly allocated to receive 12, monthly treatments of ivermectin (400 micrograms/kg), DEC (10 mg/kg) or placebo, in addition to local care of the affected limbs. There was a significant reduction in the frequency of ADL attacks in each of the three groups during the 2-year study period (P < 0.001 for each comparison). Most importantly, there were no significant differences in frequency of attacks between the three groups, either at the end of the treatment phase or at the end of the post-treatment phase (P > 0.15 for each comparison), suggesting that foot care combined with appropriate use of local antibiotics or antifungals is adequate to reduce the number of ADL attacks. The implications of these observations for planning morbidity control in lymphatic filariasis are discussed.