Innovative Water Management for Vector Control: The Case of Rice Cultivation in Burkina Faso’s Vallée du Kou

Abstract Background Water-saving techniques have the advantage of reducing the production of mosquito larvae, which could in turn reduce the density of adult mosquitoes. The aim of this study was to evaluate the impact of a new water-saving technique on reducing the number of Anopheles breeding sites in an area with a high density of the main malaria vector. Methods The study was conducted in experimental rice plots measuring 5.5 x 3.0 m (16.5 m²) from February 2024 to May 2024. Three treatment arms were implemented: i) traditional system: Deep Ploughing + Continuous Flooding (DP + CF), ii) innovative system (Minimal Tillage + Intermittent Flooding (MT + IF). Adult control was achieved by monitoring and destroying mosquito swarms. The performance of these techniques had never been compared individually or in combination. By setting up these experiments in the field, we were able to understand how to integrate these methods to obtain good rice production, save water and reduce mosquito densities. Results The results of this study show that minimum tillage combined with intermittent flooding (transplanting = 1.39, tillering = 2.81 and maturation = 0.41) resulted in a significant reduction in mean mosquito larvae densities during the rice maturation phase compared with DP + CF (transplanting = 9.13, tillering = 11.08 and maturation = 4.46) (Fisher's Exact Test: p-value < 0.05). The average density of adults collected from houses in the intervention village fell from 3.89 mosquitoes per house in the pre-intervention phase to 1.16 mosquitoes per house in the post-intervention phase, compared with 6.62 and 6.63 in the control village. A substantial reduction of more than 85% in the mosquito population at the intervention site, Vallée du Kou 2 (VK2), compared to the control site (VK3) (Fisher's Exact Test: p-value = 0.0031268). A reduction in insemination status and a shift towards younger males unable to mate was observed. Conclusions The implementation of a new approach to water saving techniques showed a substantial reduction in the mosquito population at the intervention site, which could have an effective impact on malaria transmission in the region.