School-aged children as a silent reservoir of Plasmodium falciparum: findings from a cross-sectional survey conducted in Burkina Faso in 2022

BACKGROUND: Asymptomatic Plasmodium falciparum infections sustain malaria transmission and challenge elimination efforts. School-aged children may serve as a key reservoir, yet are often overlooked in malaria control programs. METHODS: A cross-sectional survey was conducted in July 2022 across Banfora, Orodara, and Gaoua districts (Burkina Faso), enrolling 1,127 children aged from 6 months to 10 years. Malaria diagnosis was performed using HRP2-based RDT, expert microscopy, and qPCR. Children with fever (> 37.5 °C) were excluded from asymptomatic analysis. RESULTS: Prevalence of asymptomatic Plasmodium falciparum infection was 28.0% by RDT and 31.9% by microscopy. Among school-aged children (5-10 years), 66.5% tested positive by microscopy versus 21.6% in children under five. Gametocyte carriage reached 3.9% overall and was twice as high in school-aged children (67 vs. 32 gametocytes/μL). Microscopy outperformed RDT in sensitivity (76.7% vs. 67.7%), specificity (100% vs. 96.2%), and positive predictive value (100% vs. 83.8%) using qPCR as reference. Most infections were due to P. falciparum (98.2%), with mixed infections being rare. CONCLUSION: School-aged children are a major reservoir for asymptomatic and potentially infectious malaria. Their inclusion in surveillance and control strategies is critical. Expert microscopy remains a reliable field tool to detect asymptomatic carriage in high-burden areas.