Effect of two successive annual treatments with single doses of ivermectin on microfilaraemia due to Wuchereria bancrofti var. pacifica.
Between 1986 and 1988 a single-blind, dose-ranging study was carried out in French Polynesia to determine the efficacy and tolerability of single 50, 100, 150 and 200 micrograms/kg doses of ivermectin in Wuchereria bancrofti carriers. Forty male microfilariae (mf) carriers between 18 and 50 years of age, in whom mf density was greater than or equal to 20 mf/ml, were treated twice at a one-year interval. Twelve months after the second treatment, in carriers who were given a dose greater than or equal to 100 micrograms/kg, mean mf density was 4-7% of the initial pretreatment mf density. Therefore, several successive annual treatments with single doses greater than or equal to 100 micrograms/kg of ivermectin should result in reducing mf densities to a very low level. Nevertheless, at 9 months after the second treatment, residual parasitaemia ranged from 1 to 2182 mf/ml (median 85) in 30 patients. Finally, in patients with pretreatment mf counts less than or equal to 150 mf/ml, mean mf density was 2.8 and 8.9 mf/ml, respectively, during the 2 six-month periods following treatment, while in patients with pretreatment mf densities greater than 150 mf/ml (median 1500) it was 92.3 and 334.1 mf/ml during the same periods. These results suggest that, when implementing filariasis control programmes, the best strategy might be administration of several treatments with a single dose of ivermectin every 6 months to the entire population, at least in French Polynesia. Afterwards, when mf densities had been reduced to a relatively low level (100-150 mf/ml), annual treatments could be considered.
Cartel
J L
JL
Institut de Recherches Médicales Louis Malardé, Papeete, Tahiti.
Celerier
P
P
Spiegel
A
A
Plichart
R
R
Roux
J F
JF
D000293:Adolescent; D000328:Adult; D000818:Animals; D002353:Carrier State / Q000188:drug therapy*; D004334:Drug Administration Schedule; D004605:Elephantiasis, Filarial / Q000188:drug therapy*; D005500:Follow-Up Studies; D006801:Humans; D007559:Ivermectin / Q000008:administration & dosage* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011114:Polynesia; D012008:Recurrence; D014958:Wuchereria bancrofti
D007559:Ivermectin