Evaluation of lambdacyhalothrin-impregnated bednets in a malaria endemic area of India. Part 3. Effects on malaria incidence and clinical measures

In Indian villages with high malaria endemicity use of nylon bednets treate d at 25 mg/m(2) at 6-month intervals for 3 years caused significant reducti ons in malaria incidence, slide positivity rate, slide falciparum rate, ann ual parasite index, and parasite rate in the entire population, as well as reductions in rates of splenomegaly and anemia in children. In villages wit h untreated nets, considerable reduction also occurred in these parameters except for the rate of splenomegaly. In the village without nets, a relativ ely small drop occurred in the parasite rate and anemia but no change occur red in malaria incidence, and an increase occurred in the rate of splenomeg aly. The trial thus showed the efficacy of impregnated bednets against mala ria in the forested hills of Orissa State where the existing control strate gy based on indoor residual spraying of DDT has remained incapable of inter rupting malaria transmission.