Perceptions and acceptability of drone-based larviciding using Bacillus thuringiensis israelensis in rice fields in Madagascar, 2022: a qualitative study.

backgroundMadagascar's malaria burden has been increasing for several years despite continued investments in vector control. Supplemental measures to reduce vector populations and outdoor biting, such as larval source management (LSM), may be required in some settings. Madagascar piloted drone-delivered microbial larviciding using Bacillus thuringiensis israelensis (Bti) in rice fields in two districts with populations unfamiliar with drones during Feb-Jul 2022.

methodsWe assessed knowledge and perceptions among purposefully selected rice farmers, rice field workers, and community members during focus group discussions (FGDs) in the two districts three to four months after the intervention. In total, 293 people participated in 39 FGDs, which were analyzed using a combined deductive-inductive approach.

resultsDespite initial concerns, both Bti-based larviciding and using drones to apply larvicides were ultimately well accepted by rice field owners and workers and community members in rice-growing areas of Madagascar. Key concerns spanned safety of Bti for people, livestock, and the environment, and harms related to drones crashing or being used for nefarious purposes. Participants perceived decreases in mosquitoes and malaria and increased rice yield related to the intervention. Receipt of project messaging appeared to differ by demographic group, with rice field workers frequently reporting having missed community meetings while working in the fields; many participants also reported that text-heavy communications were difficult to understand. Participants appreciated the involvement of personnel from health, agriculture, and environmental sectors, and they recommended expanding such intersectoral collaboration, involving trusted local officials, hiring local actors to help plan and implement the activities, and combining larvicide and fertilizer application in subsequent projects.

conclusionsFuture LSM activities could benefit from social behavior change (SBC) efforts addressing safety and privacy concerns linked to the larvicide and the delivery method and highlight potential health and financial benefits related to decreased malaria burdens in the community, improved quality of life associated with fewer mosquito bites, the efficiency of drones in applying larvicide products, and the need to continue using ITNs. SBC will be most effective if provided early and repeatedly as needed, via channels appropriate to the community's language and literacy levels and in venues that are geographically and temporally convenient to those potentially impacted by the intervention.