Use of high-dose, twice-yearly albendazole and ivermectin to suppress Wuchereria bancrofti microfilarial levels.

Author(s): Dembele B, Coulibaly YI, Dolo H, Konate S, Coulibaly SY, Sanogo D, Soumaoro L, Coulibaly ME, Doumbia SS, Diallo AA, Traore SF, Diaman Keita A, Fay MP, Nutman TB, Klion AD

Affiliation(s): Faculty of Medicine, Pharmacy and Dentistry, Filariasis Unit, University of Bamako, Bamako, Mali.

Publication date & source: 2010-12-01, Clin Infect Dis., 51(11):1229-35. Epub 2010 Nov 1.

Publication type: Comparative Study; Randomized Controlled Trial; Research Support, N.I.H., Intramural

BACKGROUND: Annual mass treatment with albendazole and ivermectin is the mainstay of current strategies to interrupt transmission of Wuchereria bancrofti in Africa. More-effective microfilarial suppression could potentially reduce the time necessary to interrupt transmission, easing the economic burden of mass treatment programs in countries with limited resources. METHODS: To determine the effect of increased dose and frequency of albendazole-ivermectin treatment on microfilarial clearance, 51 W. bancrofti microfilaremic residents of an area of W. bancrofti endemicity in Mali were randomized to receive 2 doses of annual, standard-dose albendazole-ivermectin therapy (400 mg and 150 mug/kg; n = 26) or 4 doses of twice-yearly, increased-dose albendazole-ivermectin therapy (800 mg and 400 mug/kg; n = 25). RESULTS: Although microfilarial levels decreased significantly after therapy in both groups, levels were significantly lower in the high-dose, twice-yearly group at 12, 18, and 24 months. Furthermore, there was complete clearance of detectable microfilariae at 12 months in the 19 patients in the twice-yearly therapy group with data available at 12 months, compared with 9 of 21 patients in the annual therapy group (P < .001, by Fisher's exact test). This difference between the 2 groups was sustained at 18 and 24 months, with no detectable microfilariae in the patients receiving twice-yearly treatment. Worm nests detectable by ultrasonography and W. bancrofti circulating antigen levels, as measured by enzyme-linked immunosorbent assay, were decreased to the same degree in both groups at 24 months, compared with baseline. CONCLUSIONS: These findings suggest that increasing the dosage and frequency of albendazole-ivermectin treatment enhances suppression of microfilariae but that this effect may not be attributable to improved adulticidal activity.