Evaluation of the efficacy of Bistar 80SC by residual application in dengue vectors control in the North of Vietnam

ABSTRACT

Background: Two species, Aedes aegypti and Aedes albopictus are the main intermediate vectors of transmission of the dengue viruses in Vietnam. Insecticide applications by different methods that may help interrupt the spread of dengue outbreaks. Many different groups of insecticides have been used for dengue vector control. Some recent studies revealed that Aedes vectors obscuring their resistance to insecticides at different levels. Therefore, a new insecticide formula is required for effective dengue vectors control. Objective: To evaluate the efficacy of Bistar 80SC by residual application in suppression of Aedes species in a northern province of Vietnam. Subject and methods: Bistar 80 SC with a component of Bifenthrin 80g/L was evaluated by residual application in suppression of 2 Aedes species in vitro and in an intervention commune of Hien Giang, Thuong Tin district and a control commune of Van Mo, Ha Dong town, Ha Tay province from March, 2004 to June, 2004. Results: WHO Bifenthrin paper test kit was effective at the concentration of 37.5mg/m2 and over with Aedes aegypti vectors ranged from 80% to 100% mortality in the North, In other words, Aedes vector remains susceptible to Bifenthrin in the region. The mortality on wood surface after 60 minutes of exposure to Bistar 80SC at concentrations of 25mg/m2 by using residual application was higher than those on brick walls. Up to 100% Aedes aegypti was killed after 60 minutes in exposure and remains in effect until the end of the third months and one month with Aedes albopictus. No side effects, to the sprayer and humans, livestock and environment caused by Bistar 80SC were reported in the intervention area. Conclusion: Bistar 80SC is suggested as a nominated alternative to effectively control the dengue outbreak by residual application.