Short- and long-term action of multiple doses of ivermectin on loiasis microfilaremia.

One hundred nine Gabonese patients infected with Loa loa microfilariae were treated with ivermectin (200 microg/kg of body weight) at the Parasitology, Mycology and Tropical Medicine Department (Faculte de Medecine et des Sciences de la Sante, Libreville, Gabon). Each was given one dose per month for six consecutive months. The peripheral blood microfilaria (mf) count before and after each dose showed an average decrease in the microfilaremia of 87.3% (short-term-single dose). An annual single-dose mass treatment with 200 microg/kg of ivermectin was sufficient to control the parasite in populations with low (< 400/ml) L. loa mf counts. One month after the sixth dose (short-term-multiple doses), the average microfilaremia rate had decreased by 99.2% compared with the initial infection (35 patients). Samples were taken from 28 patients one month after the first dose and one month after the sixth dose. The average mf count decreased by 96.4% after the first dose and by 99.6% after the sixth dose (average residual mf counts = 13.7 and 1.5 mf/ml, respectively). The mf count after the sixth dose was only 11.2% of the count after the first dose. The low mf count persisted for more than six months after the sixth treatment (long-term-multiple doses). Thus, mass treatment with multiple doses is more appropriate for areas where the blood mf count is very high. These results show that the number of the annual treatments used in mass chemotherapy with ivermectin can be adapted to each population to provide efficient protection.

[Evaluation of efficacy and tolerance of amodiaquine versus chloroquine in the treatment of uncomplicated malaria outbreak in children of Gabon]. / Evaluation de l'efficacité et de la tolérance de l'amodiaquine versus chloroquine dans le traitement de l'accès palustre simple chez l'enfant au Gabon.

We conducted a prospective study from September 1997 to January 1998 in Libreville (Gabon). Fifty-three (53) children with uncomplicated P. falciparum malaria were included and divided into two groups. The first group (27 patients) was treated with amodiaquine and the second (26 patients) with chloroquine. The efficacy and tolerance of amodiaquine 30 mg/kg base over 3 days (10 mg/kg daily) and chloroquine 25 mg/kg base over 3 days (10 mg/kg day 0, 10 mg/kg day 1, 5 mg/kg day 3) were estimated at days 7 and 14. Clinical examination and parasitaemia were assessed on days 0, 1, 2, 3, 7, 14. Haematological and biochemical parameters were determined on days 0 and 7. Amodiaquine was shown to be more effective than chloroquine in clinical response and ridding patients of parasites: adequate clinical response was significantly higher with amodiaquine than chloroquine [100% (27/27) versus 45% (9/20), p < 0.0005]. Rates for early treatment failure (ETF) and late treatment failure (LTF) were respectively 35% and 12% with chloroquine. The parasitological success rate was significantly higher with amodiaquine than chloroquine on days 7 [93% (25/27) versus 62% (13/21), p < 0.008] and 14 [100% (13/13) versus 44% (4/9), p < 0.01]. The RI resistance type was 7% in the amodiaquine group. The rate of in vivo chloroquino-resistance was 53%, essentially of RII and RIII type. Overall, the two drugs were well tolerated.