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.

Keywords: French Guiana; Gold mining; Hard-to-reach population; Impact evaluation; Malaria elimination; Mathematical modelling.

© 2025 The Authors.

背景： 疟疾消除在移动和难以触及的人群中需要新颖且针对性的干预措施。在法属圭亚那，非法金矿工人群体中的疟疾病负担较高。从2018年4月到2020年3月，我们实施了针对金矿工人的新干预措施Malakit，该措施依赖于分发自我诊断和自我治疗疟疾的工具包。本研究评估了Malakit对疟疾传播的影响。

方法： 我们将数学模型拟合到巴西和苏里南的监测数据以及横断面调查中的流行率数据，以估计干预措施实施前（2014-2018）与干预期间（2018-2020）治疗覆盖率的变化，并计算繁殖数。利用反事实情景分析，我们评估了该干预对疟疾发病率的影响。

结果： 在干预期中，与实施前相比，治疗覆盖范围增加，尤其对于恶性疟原虫(Pf)疟疾（从20.6% [95% CrI 17.0, 25.7] 增加到81.7% [95% CrI 67.9, 96.4]），而对间日疟原虫(Pv)疟疾（从22.3% [95% CrI 19.3, 25.7] 增加到47.3% [95% CrI 42.6, 52.3]）的影响较小。与此同时，恶性疟原虫的平均繁殖数从0.96 (95% CrI 0.93, 1.00) 下降到0.34 (95% CrI 0.22, 0.46)，间日疟原虫则从1.13 (95% CrI 1.10, 1.16) 下降到0.86 (95% CrI 0.82, 0.90)。我们估计，Malakit在2018年至2020年期间帮助避免了总共有1231（95% CrI 589, 1870）和2406（95% CrI 1191, 3621）例由恶性疟原虫和间日疟原虫引起的症状性感染，相当于总体疟疾发病率减少了44.2% (95% CrI -52.5, -34.5)。

解读： Malakit通过改善法属圭亚那非法金矿工人群体获得治疗的机会，在疟疾传播方面产生了显著影响。在此前十五年的区域努力基础上，Malakit为加勒比地区盾牌的疟疾消除工作又迈进了一步。

资金来源： 欧洲联盟、全球基金、巴西卫生部、卡宴医院、法属圭亚那健康区域机构。

关键词： 法属圭亚那；金矿开采；难以触及的人群；影响评估；疟疾消除；数学建模