Bio-larvicidal activity of Bacillus thuringiensis on the larvae of chikungunya virus vector

Abstract

Background: Mosquitoes carry numerous diseases, such as malaria, chikungunya, yellow fever, dengue fever, and lymphatic filariasis. The control of these diseases is geared towards vector control. Still, using artificial chemical insecticides for mosquito control has been linked to the emergence of resistance and harmful impacts on both humans and the environment. Methods: Adult mosquitoes were collected, sorted, and identified using a standard identification key. Aedes spp were bred in an enclosed setting and fed with albino rat blood, sugar, and yeast. Third-stage instar larvae were used for larvicidal screening. Bacillus thuringiensis (Bt) was isolated and characterized following conventional microbiological and molecular methods. Bt bioassay was prepared into three concentrations (0.5mg/mL, 0.25mg/mL, 0.125mg/mL). Results: As the concentration of Bt increases, there is a significant decrease in the number of surviving larvae. There was a correlation between the concentration and duration of Bt exposure and the death of larvae. The higher the concentrations and more extended exposure periods, the higher the effectiveness of the Bt bioassay. A 0.5mg/mL concentration had the highest mortality rate and efficacy compared to 0.125mg/mL. Conclusion: The larvicidal assay revealed the effectiveness of Bt against Aedes larvae. The higher the concentration, the higher the mortality rate. These findings contribute to the ongoing efforts in integrated vector management, providing a sustainable and ecologically friendly alternative to synthetic insecticides for managing mosquito-borne diseases.