TRIAL OF A COMMUNITY-BASED INTERVENTION TO DECREASE INFESTATION OF AEDES-AEGYPTI MOSQUITOS IN CEMENT WASHBASINS IN EL PROGRESO, HONDURAS

Washbasins and metal drums are important sources of Aedes aegypti mosq uitoes in much of Latin America. When manual cleaning was found to be ineffective in eliminating mosquito larvae in a community-based contro l programme in El Progreso, Honduras, it was decided to develop and ev aluate an improved method of removing mosquito eggs based on commonly- available materials. The method, named La Untadita ('The Little Dab', in English), consists of five steps: mixing chlorine bleach and deterg ent to make a paste, applying the mixture to the walls of the containe r, waiting 10 min, scrubbing with a brush, and finally rinsing with wa ter. A field trial of the Untadita was conducted in 13 peri-urban neig hbourhoods. At the first post-intervention survey, in spite of high le vels of exposure to the community-based intervention, high levels of k nowledge regarding the Untadita and high levels of its reported use, l ittle or no impact was discernable on mosquito larvae and pupae. The m ethod was then modified by increasing the recommended quantities of bl each detergent and simplifying the instructions. In the second post-in tervention survey, knowledge of the steps and their order increased fu rther; the intervention neighbourhoods had significantly fewer algae o n washbasin walls, an indicator of more effective cleaning; and number s of pupae and 3rd and 4th instar larvae were significantly lower than in untreated neighbourhoods. Effective promotion of the Untadita shou ld be able to control mosquito infestation in many washbasins, especia lly those in frequent use, thus reducing the need for chemical and bio logical larvicides that may be either more costly or less acceptable t o householders. (C) 1998 Elsevier Science B.V. All rights reserved.