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. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Cayenne Hospital, as sponsor, directly managed most of the project funds. Half of the funding was by the European Regional Development Fund via the Interregional Amazon Cooperation Program 2014-2020, supplemented with self-funding from Cayenne Hospital, funds from the French Guiana Health Regional Agency, the European Horizon 2020 Program and contributions in kind from the Suriname National Malaria Program, as beneficiary of the Global Fund to Fight AIDS, Tuberculosis and Malaria; the Ministry of Health of Brazil; and the French Development Agency. The funding bodies played no part in the implementation and evaluation of the project. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Pre-intervention surveys: In Suriname: Approval from the CMWO(Commissie voor Mensgebonden Wetenschappelijk Onderzoek) (Opinion Number VG10-14) In Brazil: Approval from the Fiocruz Ethics Committee (Opinion Number 2.560.415) Malakit Intervention: In Suriname: Approval from the CMWO (Opinion Number VG 25-17) In Brazil: Approval from the Fiocruz Ethics Committee (Opinion Number 2.831.534) [ClinicalTrials.gov][1] Registration number: [NCT03695770][2] Post-intervention surveys: In Suriname: Approval from the CMWO (Opinion Number DVG-738) In Brazil: Approval from the Fiocruz Ethics Committee (Opinion Number 2.560.415) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors * ACT : Artemisinin combined therapy ITSA : Interrupted time series analysis LLIN : Long lasting insecticidal net NSI : New symptomatic infection NSI/1000/year : New symptomatic infections per 1000 individuals PCR : Polymerase chain reaction Pf : Plasmodium falciparum Pv : Plasmodium vivax RDT : Rapid diagnostic test S-PQ : Single-dose primaquine [1]: http://ClinicalTrials.gov [2]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT03695770&atom=%2Fmedrxiv%2Fearly%2F2023%2F07%2F13%2F2023.07.11.23292527.atom