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Introduction: The use of long lasting insecticidal materials has shown promising results in the control of Aedes aegypti., Objective: To evaluate the efficacy of long-lasting insecticidal nets (PermaNet®) for Aedes aegypti control after three washing treatments in the city of Girardot, Colombia., Materials and Methods: Standard bioassays were conducted with the nets following the World Health Organization protocols using wild A. aegypti after three washing treatments: (1) Detergent powder, (2) detergent powder and bleach, and (3) bar soap, until completing 20 washes., Results: The type and number of wash treatments had a significant effect on net efficacy. Greater effects in the insecticide bioavailability were seen for the bar soap treatment. After six washes, mortality decreased by 50% (25/50), vs 66% (33/50) for the detergent powder and 84% (42/50) for the detergent powder and bleach treatments. Regarding the number of washes, the bar soap treatment reduced the efficacy to 68% after only three washes., Conclusion: The effectiveness of long-lasting insecticidal nets (PermaNet 2.0) for A. aegypti control varied in relation to the treatment and number of washes. The bar soap treatment resulted in the greatest reduction of mortality. Further studies on insecticidal reductions are needed under local conditions.

Background: Long-lasting insecticide-treated net (LLIN) window and door curtains alone or in combination with LLIN water container covers were analysed regarding effectiveness in reducing dengue vector density, and feasibility of the intervention., Methods: A cluster randomised trial was conducted in an urban area of Colombia comparing 10 randomly selected control and 10 intervention clusters. In control clusters, routine vector control activities were performed. The intervention delivered first, LLIN curtains (from July to August 2013) and secondly, water container covers (from October to March 2014). Cross-sectional entomological surveys were carried out at baseline (February 2013 to June 2013), 9 weeks after the first intervention (August to October 2013), and 4-6 weeks after the second intervention (March to April 2014)., Results: Curtains were installed in 922 households and water container covers in 303 households. The Breteau index (BI) fell from 14 to 6 in the intervention group and from 8 to 5 in the control group. The additional intervention with LLIN covers for water containers showed a significant reduction in pupae per person index (PPI) (p=0.01). In the intervention group, the PPI index showed a clear decline of 71% compared with 25% in the control group. Costs were high but options for cost savings were identified., Conclusions: Short term impact evaluation indicates that the intervention package can reduce dengue vector density but sustained effect will depend on multiple factors., (© The author 2015. The World Health Organization has granted Oxford University Press permission for the reproduction of this article.)