Activities of Artemether-Lumefantrine and Amodiaquine-Sulfalene-Pyrimethamine against Sexual-Stage Parasites in Falciparum Malaria in Children

Abstract

The activities of artemether-lumefantrine and amodiaquine-sulfalene-pyrimethamine against sexual-stage parasites were evaluated in 42 of 181 Nigerian children with uncomplicated Plasmodium falciparum malaria who had gametocytaemia before, during or after treatment with the two combination therapies. The children were randomized to the standard dose regimens. Clinical recovery from illness occurred in all children who carried gametocytes. Gametocytaemia was detected in 20 patients (11%) before treatment and in another 22 patients (12.2%) after treatment. Gametocyte carriage rates were similar in both combination treatment groups, but the area under the curve of gametocytaemia plotted against time was 8-fold higher in the amodiaquine-sulfalene-pyrimethamine-treated than in the artemether-lumefantrine-treated children. The pretreatment gametocyte sex ratio was female biased in both treatment groups. During follow-up, there was a short-lived but significant increase in the gametocyte sex ratio in children treated with amodiaquine-sulfalene-pyrimethamine but not in those treated with artemether-lumefantrine. These results indicate that both combination therapies had moderate effects on gametocyte carriage, but artemether-lumefantrine may be more potent at reducing transmissibility in P. falciparum malaria by exerting greater effects on post-treatment gametocyte density and gametocyte sex ratio.