Innovative water management for vector control: the case of rice cultivation in Burkina Faso’s Vallée du Kou

Abstract

BACKGROUND: A new water-saving techniques involves minimal tillage and intermittent flooding has 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: ) from February 2024 to May 2024. Three treatments were implemented: (i) deep ploughing combined with intermittent flooding (DP + IF), (ii) minimum tillage with continuous flooding (MT + CF), and (iii) minimum tillage with intermittent flooding (MT + IF), the latter representing a novel approach. The traditional farming system, deep ploughing with continuous flooding (DP + CF) was used as the control for comparative analysis. Control of adult mosquitoes was conducted through systematic monitoring and elimination of swarms. To date, the performance of these techniques, whether individually or in combination, had not been comparatively evaluated. RESULTS: The results of this study demonstrate that minimum tillage combined with intermittent flooding significantly reduced larval densities, by up to 80% at the transplanting stage and nearly 85% at maturation (Kruskal-Wallis test, p-value < 0.05). The reduction was less pronounced during the tillering stage. 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) was observed (Fisher's Exact Test: p-value = 0.003). A reduction in insemination status and a shift towards younger males unable to mate was observed. CONCLUSIONS: The combination of minimal tillage with intermittent flooding and targeted swarm control substantially reduced mosquito populations and shows promise as an integrated malaria vector control strategy.