Spatial and temporal trends of conjunctivitis in Uganda, 2020–2023: A nationwide surveillance analysis

Introduction: Conjunctivitis is a common ocular condition with multiple infectious and non-infectious causes and remains an important public health concern in low-resource settings. However, national data on temporal and spatial trends of conjunctivitis in Uganda are limited. This study described the epidemiology, temporal trends, and spatial distribution of conjunctivitis in Uganda from 2020 to 2023 to inform prevention and control strategies. Methods: We conducted a descriptive cross-sectional analysis of routine conjunctivitis surveillance data reported through the District Health Information Software version 2 (DHIS2) from January 2020 to December 2023. Cases were classified as allergic, infectious, or other forms based on clinical diagnosis. Incidence rates were calculated per 1,000 population using projected population denominators disaggregated by sex, region, and year. Age-specific incidence was estimated using national demographic proportions (<5 years: 15%; ≥5 years: 85%). Temporal trends were assessed using monthly and quarterly incidence, with significance tested using the Mann–Kendall trend test. Spatial distribution was analyzed at the district level using QGIS. Results: A total of 4,550,193 conjunctivitis cases were reported nationally; females accounted for 2,548,108 (56%), and children under five years contributed 1,456,062 (32%). Allergic conjunctivitis comprised the highest proportion of cases, 2,184,092 (48%). Mean annual incidence was highest for infectious conjunctivitis, particularly in Karamoja, West Nile, Kigezi, and Acholi. Children under five experienced markedly higher incidence across all etiologies, especially reaching 380 per 1,000 population in Karamoja. Allergic conjunctivitis showed a significant increasing temporal trend (p = 0.004), while infectious conjunctivitis remained stable with recurrent outbreak peaks. Spatial analysis revealed expanding allergic conjunctivitis burden in central and western Uganda, and persistent infectious conjunctivitis hotspots in northern and northeastern regions. Conclusion: Conjunctivitis remains a substantial public health burden in Uganda, with distinct patterns by aetiology, age group, sex, and geography. The rising trend of allergic conjunctivitis and persistent infectious conjunctivitis hotspots among young children highlights the need for strengthened surveillance, targeted WASH interventions, environmental health strategies, and early outbreak detection, particularly in high-risk and densely populated settings.