Burden of Shigella infection in children under five years living in a peri-urban area of Ouagadougou, Burkina Faso: A community-based cohort study

BACKGROUND: Shigella is a leading cause of childhood diarrheal disease and a priority target for vaccine development, particularly in low-resource settings where its true burden is often underestimated. A clear understanding of local Shigella epidemiology and risk factors is essential for guiding control strategies and vaccine introduction. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a 12-month longitudinal cohort study enrolling 750 children under five years of age in a peri-urban area of Ouagadougou, Burkina Faso, from December 2020 to March 2021, with follow-up through March 2022. Active and passive surveillance captured both symptomatic and asymptomatic infections. Stool samples (n = 2,401), including 236 from diarrheal episodes, were analyzed by conventional microbiological methods with species confirmation using the BD Phoenix M50 system. Shigella was isolated from 56 incident cases, yielding an incidence rate of 6.8 cases per 1,000 child-months (95% CI: 5.3-8.9). Shigella flexneri predominated (58.9%), followed by S. boydii (23.2%), S. sonnei (14.3%), and S. dysenteriae (3.6%). Incidence among diarrheal cases was 39.2 per 1,000 child-months (95% CI: 24.7-62.2), alongside substantial asymptomatic carriage (4.9 per 1,000 child-months). Shigellosis was strongly associated with diarrhea, predominantly mucoid rather than bloody stools. Young age was a significant predictor, particularly at 12-23 months (aHR = 2.68; 95% CI: 1.11-6.47) and 36-47 months (aHR = 2.81; 95% CI: 1.08-7.33), while use of a public water source was independently protective (aHR = 0.52; 95% CI: 0.29-0.94). CONCLUSIONS/SIGNIFICANCE: This study provides foundational incidence and serotype data for Shigella among young children in peri-urban Burkina Faso, informing future vaccine development and targeted public health interventions. The findings highlight the need to strengthen water, sanitation, and hygiene programs, improve diagnostic capacity, and enhance antimicrobial resistance surveillance to reduce Shigella transmission and impact in this population.