Epidemiology of Relapsing and Falciparum Malaria in the Highlands of Cameroon: An Integrated Community Survey of Human Infection and Vector Abundance.

Despite global malaria control efforts, the disease caused 263 million cases and 597,000 deaths in 2023. While accounts for most cases in Africa, non-falciparum species, such as spp. and , can cause relapse infections and are increasingly recognized as significant contributors to human disease. In particular, the highlands of West Cameroon have previously been reported to have high infection rates. This study presents preliminary results from the Relapsing Malaria in Africa (ReMA) study, conducted in Dschang, Cameroon, to assess the prevalence and epidemiology of and . A cross-sectional survey of 3,661 participants from 871 households across seven health areas identified a low prevalence of (0.1%) and spp. (0.64%) using quantitative real time PCR (qPCR), while remained prevalent at 8.1%. Co-infections of spp. with were observed in 23.1% of spp. cases. While gametocytemia was common among falciparum infections, leveraging a new ovale gametocyte assay, we found that gametocytemia was uncommon among the qPCR-positive ovale infections. Spatial analysis found and spp. infections concentrated in Penka-Michel and Baleveng, the former having higher spp. abundance than other areas assessed. Risk factor analysis revealed children and those with recent domestic travel had higher odds of infection, but no significant associations were found for spp. infections. Entomological surveys confirmed high densities of () and (s.l.), with significantly higher human landing capture rates for s.l compared to other mosquito species. While these findings suggest that the relapsing malarias are not as widespread as previously thought in West Cameroon, understanding factors driving their persistent transmission, especially without prevalent gametocytemia, will be important for disease control.