Treatment of bancroftian filariasis in Recife, Brazil: a two-year comparative study of the efficacy of single treatments with ivermectin or diethylcarbamazine

Abstract

The effectiveness of single oral doses of ivermectin (200 or 400 micrograms/kg) and diethylcarbamazine (DEC, 6 mg/kg), preceded 4 d earlier by either placebo or very small doses of these drugs, was compared, over a 2-year period, in a double-blind trial in 67 microfilaraemic Brazilian men with bancroftian filariasis. Regimens containing ivermectin alone decreased the number of microfilariae significantly faster and more effectively for the first month after treatment than regimens containing DEC alone, but the latter were significantly more effective throughout the second year after treatment (1.7-8.2% of pretreatment levels with DEC vs. 12.6-30.8% with ivermectin during that period); the higher ivermectin dose showed a tendency towards more effectiveness than the lower dose. Most effective was the combination of ivermectin (20 micrograms/kg) followed 4 d later by DEC (6 mg/kg), with reduction of microfilaraemia to 2.4% of pretreatment levels at 2 years. Adverse reactions were well tolerated with all regimens, the reactions being significantly more generalized (i.e., fever) following ivermectin and localized (i.e., scrotal inflammatory nodules around dying adult worms) following DEC. Further trials of single-dose combination therapy vs. single high doses of ivermectin or DEC should determine the ideal regimen for treatment and control of bancroftian filariasis.

Perturbations in Eosinophil Homeostasis following Treatment of Lymphatic Filariasis

“…Reflective of many similar findings in the literature (10,21,30), the peripheral microfilarial count fell precipitously at 24 h following treatment, followed by an increase in their number and a subsequent slower decline. Administration of DEC, a micro-and macrofilaricidal drug, and/or ivermectin, a microfilaricidal drug, leads to rapid killing of microfilariae in the circulation and an immediate inflammatory response characterized in most patients by a brief serum sickness-like illness and eosinophilia.…”

Long-term persistence of cellular hyporesponsiveness to filarial antigens after clearance of microfilaremia.

“…In the present study, five (62.5%) of eight mfϩ patients had been treated with combination single-dose therapy, while 89% (8 of 9) of the mfϪ group were treated with combination therapy. This would suggest that although a singledose of either drug appears to be completely effective in initial microfilarial clearance, [35][36][37] the combination of ivermectin and DEC is more effective for long-term suppression of microfilaremia or cure. 38 Therefore, as has been proposed, 39 implementation of yearly single-dose therapy with DEC and/or ivermectin would be indicated to establish and maintain a decrease in the reservoir of infection.…”

Antifilarial activity of a synthetic marine alkaloid, aplysinopsin (CDRI Compound 92/138)

“…The candidate drug ivermectin, though very effective against microfilariae of different filaids in single or divided semi-annual or annual dose regimens (Kumaraswami et al 1988;Coutinho et al 1994), is ineffective against adult filariae (Dreyer et al 1995(Dreyer et al , 1996. Nevertheless, due to its rapid clearance of microfilariae from blood, ivermectin may cause an equal, if not more severe, reaction than DEC (Ottesen 1987;Richards et al 1991).…”