Modeling the impact of Malakit intervention: one more step towards malaria elimination in the Guiana Shield?

Background Malaria elimination in mobile and hard-to-reach populations calls for new, tailored interventions. In the Guiana Shield countries, the malaria burden is high in 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 self-diagnosis and self-treatment. In this study, we evaluate the impact of Malakit on malaria transmission. Methods We fitted a mathematical model of malaria transmission to surveillance data from Brazil and Suriname, and to prevalence data from cross-sectional surveys, to estimate the change in treatment coverage and reproduction number between the pre-intervention (2014-2018) and intervention (2018-2020) periods. Results Model results show that treatment coverage of symptomatic all-species malaria infections increased from 26.4% (95%CrI 22.8, 30.3) prior intervention to 55.1% (95%CrI 49.9, 60.8) during the intervention, leading to a decrease of the reproduction number from 1.19 to 0.86. We estimate that on average 6943 all-species malaria infections were averted during the intervention, corresponding to a 48.7% reduction in incidence and 43.9% reduction in total infection prevalence. Discussion Malakit had a significant impact on malaria transmission by improving the access to treatment of the population working in illegal gold mining in French Guiana. Building on the regional efforts of the past twenty years, Malakit contributed to another step towards malaria elimination in the Guiana Shield.