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Context: The Democratic Republic of Congo (DRC), one of the most malaria-affected countries worldwide, is a potential hub for global drug-resistant malaria. This study aimed at summarizing and mapping surveillance surveys of malaria parasites carrying molecular markers of drug-resistance across the country. Methods: A systematic mapping review was carried out before July 2023 by searching for relevant articles through seven databases (PubMed, Embase, Scopus, African Journal Online, African Index Medicus, Bioline and Web of Science). Results: We identified 1541 primary studies of which 29 fulfilled inclusion criteria and provided information related to 6385 Plasmodium falciparumclinical isolates (collected from 2000 to 2020). We noted the PfCRT K76T mutation encoding for chloroquine-resistance in median 32.1% [interquartile interval, IQR: 45.2] of analyzed malaria parasites. The proportion of parasites carrying this mutation decreased overtime but wide geographic variations persisted. A single isolate had encoded the PfK13 R561H substitution that is invoked in artemisinin-resistance emergence in the Great Lakes region of Africa. Parasites carrying various mutations linked to resistance to the sulfadoxine-pyrimethamine combination were widespread and reflected a moderate resistance profile (PfDHPS A437G: 99.5% [IQR: 3.9]; PfDHPS K540E: 38.9% [IQR: 47.7]) with median 13.1% [IQR: 10.3] of them being quintuple IRN-GE mutants (i.e., parasites carrying the PfDHFR N51I-C59R-S108Nand PfDHPS A437G-K540E mutations). These quintuple mutants tended to prevail in eastern regions of the country. Among circulating parasites, we did not record any parasites harboring mutations related to mefloquine-resistance, but we could suspect those with decreased susceptibility to quinine, amodiaquine, and lumefantrine based on corresponding molecular surrogates. Conclusion: Drug resistance poses a serious threat to existing malaria therapies and chemoprevention options in the DRC. This review provides a baseline for monitoring public health efforts as well as evidences for decision-making in support of national malaria policies and for implementing regionally tailored control measures across the country.

Background Despite their potential to undermine malaria control and elimination efforts, infected adults who live in endemic areas are an overlooked aspect of public health strategies. We aimed to estimate the prevalence of malaria, to identify underlying parasites species, and to assess predicting factors among adults residing in an endemic area from the Democratic Republic of Congo (DRC). Methods A community-based cross-sectional survey included subjects aged 18 years and above who were interviewed using a standard questionnaire and tested for malaria using a rapid diagnostic test and a nested polymerase chain reaction assay. Logistic regression models were fitted to assess the effect of potential predictive factors on malaria infection. Results The prevalence of malaria was estimated 60.2% [95%CI: 55.5; 64.8] in this population category. Parasite species identified included P. falciparum (87.4%), P. malariae (39.9), and P. ovale (7.5%) which occurred primarily as single species infections of P. falciparum ( 55.3% of malaria cases) and mixed P. falciparum/ P. malariae infections (26.1%). Putative episodes of clinical malaria dated back more than a month in 50% of participants whereas no episode was evoked within a 48-hours period interval prior to the survey. The likelihood of malaria infections decreased significantly with age (adjusted odds ratio, aOR = 0.98 [95%CI: 0.87; 0.98]; p = 0.006) and indoor insecticide spraying (aOR = 0.1 [95%CI: <0.01; 0.58]; p = 0.032). Conclusion Adults infected with malaria constitute a potentially important latent reservoir for the transmission of the disease in the study setting. They should specifically be taken into account in public health measures and translational research.