The Effectiveness of Net to Reduce the Entomological Indices in Dengue-Endemic Areas in Balikpapan, Indonesia

BACKGROUND: Drums and cisterns are ubiquitous water storages in Indonesian households, seldom being drained and left open to create access for the rainwater, providing a favorable breeding site for dengue vector. The bigger the container, the more it produces immature mosquitoes that are soon to be mature, increasing the entomological indices and raising the potency of cases in the area. Previous studies revealed that the net covering the reservoirwas able to effectively protect the water from mosquito oviposition; therefore, a modification of the net was made.
AIM: The aim of this study is to discover whether the net as a cover for water containers is effective in reducing the entomological indices in dengue-endemic areas.
METHODS: The quasi-experimental study with pretest and posttest control group design, involved 3 intervention and 3 control clusters, 150 houses which have 672 water-holding containers with 116 large containers were intervened with non-insecticide tulle nets for 3 months. The larval presence data were performed by larval survey.
RESULTS: It revealed that net reduced the container index (CI) in intervened large containers 18%–84% as well as the environment entomological indices in general in study areas: CI decreased 75%–79%, house index decreased 65%–70%, and Breteau index decreased 75.5%–78.7%, while Free Larva Index rose 73.7%–88%.
CONCLUSIONS: The nets had lowered the CI in the intervened large container and affected the entomological indices of the surrounding environment, by blocking the mosquitos-water contact and preventing the young mosquitos that had developed in the containers from flying out.