Evidence of co-circulation and co-exposure to arboviruses and malaria in a longitudinal cohort in Kenya from 2019 to 2022

Chikungunya virus (CHIKV), dengue virus (DENV), and malaria have gained significant concern in sub-Saharan Africa. The similar epidemiology, endemicity and clinical presentation of the diseases caused by these pathogens underscore the need to investigate the burden and emergence of mixed infections and the potential factors that increase the risk of coexistence and co-circulation of these pathogens. In this study, we determine the burden of co-exposure and co-infection of CHIKV, DENV, and malaria in Kenya and describe the associated risk factors. We followed 4,534 study participants from December 2019 to February 2022 on the coast (Ukunda) and west (Kisumu) of Kenya to quantify the burden of CHIKV, DENV, and malaria co-infections and recent and lifetime co-exposure. The results highlight 15.5% acute malarial infection, 0.7% acute DENV infection, and 0.06% acute CHIKV infection in our cohort. No acute co-infection was detected. The lifetime co-exposure to DENV and malaria was 0.75% and CHIKV and malaria was 1.8%. We estimated ~ 0.2% of the study population to be co-exposed to DENV, CHIKV, and malaria. The study highlights the importance of higher socioeconomic status, mosquito prevention methods, and sleeping under the bed nets to decrease the co-exposure to DENV, CHIKV, and malaria and, crowding and presence of water containers to increase the co-exposure to DENV, CHIKV, and malaria.