Insecticide-treated curtains reduce the prevalence and intensity of malaria infection in Burkina Faso

A large, randomized controlled trial to investigate the impact of insectici de-treated curtains (ITC) on child mortality was conducted in an area of se asonal, holoendemic malaria in Burkina Faso. 158 communities totalling some 90 000 people were censused and grouped into 16 geographical clusters, 8 o f which were randomly selected to receive ITC in June - July; 1991, just pr ior to the rainy season. In September - October 1995, at the peak period of malaria transmission, a cross-sectional survey was conducted in 84 of the villages. A random sample of 905 children aged 6-59 months was identified a nd visited. 763 children (84%) were present at the time of the visit and re cruited into the study. Mothers were asked about fever in the past 24 h, th e chili's temperature was taken, and a sample of blood collected to identif y and quantify malaria infections and to measure haemoglobin (Hb) levels. C hildren protected by ITC were less likely to be infected with plasmodium fa lciparum (risk ratio = 0.92; 95% CI 0.86,0.98) or P. malariae (risk ratio = 0.42, 95%, CI 0.19,0.95). The mean intensity of P. falciparum infections w as lower among children protected by ITC (899 vs. 1583 trophozoites/mu l; P < 0.001), while the mean Hb level was 0.4 g/dl higher (P < 0.001). While w e found no evidence that ITC had an impact on the prevalence of malaria-ass ociated fever episodes, the confidence intervals around our estimates of th e impact of ITC on malaria morbidity were wide. We conclude that widespread implementation of ITC in this area of high malaria transmission led to a m odest reduction in the prevalence of malaria infection and to a more substa ntial reduction in the intensity of these infections which caused increased Hb levels. We were unable to demonstrate any impact of ITC on malaria morb idity, but the wide confidence intervals around our point estimates do nor preclude the possibility of a substantial impact.