Résumé
Background: Malaria elimination in mobile and hard-to-reach populations calls for novel, tailored interventions. In French Guiana, the malaria burden is high among the population working in illegal gold mining. Between April 2018 and March 2020, we implemented Malakit, a new intervention targeting gold miners, and relying on the distribution of kits for the self-diagnosis and self-treatment of malaria. In this study, we evaluate the impact of Malakit on malaria transmission.Methods: We fitted mathematical models of the transmission of Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) to surveillance data from Brazil and Suriname and to prevalence data from cross-sectional surveys to estimate the change in treatment coverages and reproduction numbers between the pre-intervention (2014-2018) and intervention (2018-2020) periods. Using counterfactual scenario analysis, we estimated the impact of the intervention on malaria incidence.Findings: Treatment coverage increased in the intervention compared to the pre-intervention period, the effect being stronger for Pf malaria (from 20.6% [95% CrI 17.0, 25.7] to 81.7% [95% CrI 67.9, 96.4]) than Pv malaria (from 22.3% [95% CrI 19.3, 25.7] to 47.3% [95% CrI 42.6, 52.3]). Concomitantly, the mean reproduction number decreased from 0.96 (95% CrI 0.93, 1.00) to 0.34 (95% CrI 0.22, 0.46), for Pf, and from 1.13 (95% CrI 1.10, 1.16) to 0.86 (95% CrI 0.82, 0.90) for Pv. We estimated that between 2018 and 2020 Malakit helped avert a total of 1231 (95% CrI 589, 1870) and 2406 (95% CrI 1191, 3621) symptomatic infections by Pf and Pv, respectively, corresponding to a 44.2% reduction of the overall malaria incidence (95% CrI -52.5, -34.5).Interpretation: Malakit had a significant impact on malaria transmission by improving the access to treatment for the population working in illegal gold mining in French Guiana. Building on the regional efforts of the past fifteen years, Malakit contributed to another step towards malaria elimination in the Guiana Shield.Funding: European Union, Global Fund, MoH of Brazil, Cayenne Hospital, Health Regional Agency of French Guiana.