Prevalence and risk factors of asymptomatic Plasmodium spp. infection in the military population of the Colombian National Army

BACKGROUND: Asymptomatic malaria plays a critical role in sustaining transmission in endemic regions, yet its magnitude and determinants remain insufficiently characterized in military populations frequently exposed during field operations. This study sought to estimate the prevalence of asymptomatic Plasmodium spp. infection and identify associated risk factors among Colombian military personnel deployed in high-endemicity areas in 2022. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional survey was conducted in four departments with the highest malaria transmission (Antioquia, Chocó, Córdoba, and Nariño). A total of 773 participants underwent thick blood smear microscopy, rapid diagnostic testing (RDT), conventional PCR, and real-time PCR. The prevalence of asymptomatic infection detected by conventional PCR/qPCR was 2.59%, with the highest municipal rates observed in El Bagre and Carepa (Antioquia), followed by Tumaco, Quibdó, and Tierralta. P. falciparum accounted for most infections (60%), followed by P. vivax (25%) and mixed infections (15%). qPCR demonstrated the greatest diagnostic sensitivity. Statistical analyses identified frequency of bed net use, number of lifetime and recent malaria episodes, department of origin, department and duration of patrol, number of patrol sites, and age as the main associated risk factors. CONCLUSIONS/SIGNIFICANCE: These findings highlight the relevance of asymptomatic Plasmodium spp. infections among Colombian military personnel and underscore the need to integrate their detection into routine malaria surveillance. Strengthening identification of low-density infections in highly exposed populations may contribute to reducing transmission, improving clinical management, and enhancing operational readiness in endemic areas.