THE EFFECTS OF HOUSE SPRAYING WITH DDT OR LAMBDA-CYHALOTHRIN AGAINST ANOPHELES-ARABIENSIS ON MEASURES OF MALARIAL MORBIDITY IN CHILDREN IN TANZANIA

The effects of house spraying of DDT and lambda-cyhalothrin against po pulations of Anopheles arabiensis were assessed in children aged betwe en 1 and 10 years with regard to fever episodes and parasite prevalenc es. DDT and lambda-cyhalothrin treatment did not reduce the prevalence of malaria episodes as defined by fever (temperatures greater-than-or -equal-to 37.4-degrees-C and/or fever reported) combined with high par asitaemia (greater-than-or-equal-to 100 parasites/200 leucocytes). How ever, the prevalence of malaria parasitaemia, of the episodes of fever with any level of malaria parasitaemia and of high parasitaemia alone were significantly reduced. Furthermore, the reduction in mean parasi te densities was greater in children of the 1-2 years age group for bo th insecticides and also for children of 3-5 years age group with lamb da-cyhalothrin. Measured and/or reported fever and high parasitaemia w ere correlated and the data indicated that most of the fevers in these children could be attributed to malaria. Using this criterion it is c oncluded that the population of An. arabiensis responded to both DDT a nd lambda-cyhalothrin house spraying which in tum also reduced malaria -related morbidity.