The impact of indoor residual spraying with malathion on malaria in refugee camps in eastern Sudan

An exploratory trial of the efficacy of indoor spraying with malathion on m orbidity and mortality in refugee camps in eastern Sudan was conducted duri ng the rainy season of 1997. The interior walls of houses from a randomly s elected group of five camps were sprayed with malathion in mid-September an d morbidity and mortality rates in the camps for the months October to Dece mber compared with rates in five controls. Pyrethrum spray collection and h uman landing catches were performed in two collection rounds. An exophagic but endophilic population of Anopheles arabiensis was the most common mosqu ito collected. The mean human blood index of 242 mosquitoes from eight camp s was 0.51. Only two of 1040 mosquitoes examined harboured sporozoites. Blo od samples of 83 putative malaria patients were examined for parasites by P CR. Mortality rates in the 3 months following spraying were significantly l ower in sprayed camps although differences in clinical malaria incidence be tween sprayed and non-sprayed camps were not significant. (C) 2001 Elsevier Science BN. All rights reserved.