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Mosquito control in Dar es Salaam. II. Impact of expanded polystyrene beads and pyriproxyfen treatment of breeding sites on Culex quinquefasciatus densities
Abstract: In 2 contrasting areas of Dar es Salaam (Tanzania), Ilala and Mikocheni, all enclosed 'breeding' sites of C. quinquefasciatus, such as latrines and septic tanks, were treated with a floating layer of expanded polystyrene beads. 7 months later checks in both study areas revealed only 1 site (from which the polystyrene had been removed during emptying) containing immature stages of C. quinquefasciatus. Open breeding sites such as areas of flooded land and blocked drains were treated with pyriproxyfen (an insect growth regulator) at a concentration of 0.1 ppm. Emergence of C. quinquefasciatus adults from these sites was inhibited for 4 weeks during the rainy season and for up to 11 weeks during the dry season. The problem of mosquito breeding sites caused by bathroom sullage water was addressed through a combination of health education and indirect pressure from the Urban Malaria Control Project (UMCP) via local community leaders. Households responsible for these sites were encouraged to eliminate them by diverting the water into an enclosed drainage structure, usually a pit latrine. After 2 weekly visits, 64.7% of households had complied and 93.4% had complied after 5 visits. Five months later, only 15.7% had reverted to allowing sullage water to collect into puddles. Densities of C. quinquefasciatus adults dropped 76.7% in Mikocheni and by 46.2% in Ilala following intervention, but increased by 84.9% and 25.6% in 2 untreated comparison areas. The reasons for differential success of the combined interventions in the 2 treated areas are discussed.











































