APPROACHES TO VECTOR CONTROL - NEW AND TRUSTED .4. APPROPRIATE TECHNOLOGY FOR VECTOR CONTROL - IMPREGNATED BED NETS, POLYSTYRENE BEADS AND FLY TRAPS

There are social, economic and entomological problems with conventiona l insecticidal spraying methods for vector control. There is therefore interest in alternative technologies, especially the impregnation of bed nets with pyrethroid insecticides against malaria vectors. This me thod is cheap, socially acceptable and effective where bed nets are al ready widely used and where malaria transmission is not very intense. In holoendemic areas, and where people consider bed nets unaffordable, there are still unanswered questions. Whether pyrethroid resistance w ill be selected in anophelines also deserves more attention than it ha s so far attracted. Where Culex mosquitoes breed in confined sites suc h as pit latrines, the application of floating layers of polystyrene b eads is a long-lasting and effective control method. There is increasi ng evidence that house flies are important agents in the mechanical tr ansmission of diarrhoea due to Shigella. Simple fly traps can be an ef fective way of controlling house fly populations and this deserves com prehensive testing in tropical countries.