Malaria infection among adults residing in a highly endemic region from the Democratic Republic of the Congo

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.