The effects of a pre-season treatment with effective antimalarials on subsequent malaria morbidity in under five-year-old children living in high and seasonal malaria transmission area of Burkina Faso

Abstract

To evaluate the effects of pre-season treatment with single dose of sulfadoxine-pyrimethamine (SP) or artemether-lumefantrine (AL) on subsequent malaria morbidity in under-fives. A cohort of 156 children was enrolled for longitudinal follow-up. Children received curative therapy with SP or AL, and a third group received no treatment. Participants were home-visited twice a week with blood smears taken from children with fever (axillary T° ≥ 37.5 °C) or history of fever. To assess the time to re-infection, a blood film was also systematically obtained from pre-treated children every 2 weeks. The mean time to the first malaria infection was 36 days in the SP arm and 26 days in the AL arm (P=0.006). The incidence density of malaria infection was similar in both groups (86.5%vs. 92.3%, P=0.52). The mean time to the first malaria episode was 47 days in the SP arm and 32 days in the AL arm (P<0.001). The incidence of malaria episodes was significantly higher in the group pre-treated with AL (45.7 per 1000 child days-at-risk CI 95% [35-56]) than in the control group (10.7 per 1000 child days-at-risk CI 95% [7-15]); P<0.001). Our findings suggest that the radical clearance of parasitemia with AL may increase susceptibility to malaria infection and clinical malaria episodes.