Plasmodium falciparum Malaria and Arbovirus Co-Exposure in the Boende Health Zone, Northwestern Democratic Republic of the Congo.

Background

Malaria remains hyperendemic in the Democratic Republic of the Congo, while arboviral infections are increasingly reported but remain under-surveilled, particularly in remote regions. Overlapping ecological niches and non-specific clinical presentations complicate case management and surveillance.

Methods

A cross-sectional door-to-door survey was conducted in December 2023 in Inkanamongo village (Lokolia Health Area, Boende Health Zone, Tshuapa Province). Blood samples were collected from 379 adults; malaria infection was assessed by using HRP2-based rapid diagnostic tests, and arboviral IgG antibodies were measured on dried blood spots using Luminex® multiplex immunoassay. Sociodemographic data were collected via standardized questionnaires.

Results

Malaria prevalence was 51.7% (95%CI: 46.7-56.7). Overall arboviral seroprevalence reached 78.4% (95%CI: 73.1-81.5), dominated by O'nyong-nyong virus, 42.8% (95%CI: 37.6-47.5), Rift Valley fever virus, 32.0% (95%CI: 26.9-36.2), and chikungunya virus, 23.4% (95%CI: 19.0-27.4). Concurrent malaria infection and arboviral exposure were observed in 40.4% (95%CI: 35.6-45.4) of participants. No sociodemographic factors were significantly associated with co-exposure in the multivariable analysis.

Conclusions

Substantial co-exposure of malaria and multiple arboviruses occurs in this remote Congo Basin setting. Integrated surveillance and improved diagnostics are urgently needed to guide febrile illness management and preparedness in under-resourced regions.