Re-examining the Meningitis Belt: Associations Between Environmental Factors and Epidemic Meningitis Risk Across Africa
medRxiv
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Abstract: This research revisits the 2002 Molesworth et al. model that defined Africa?s meningitis belt through environmental risk profiling. Using 20 years (2003?2022) of WHO outbreak data and high-resolution reanalysis datasets (rainfall, aerosol/dust, humidity), the study applies k-means clustering and logistic regression to evaluate how environmental variables correlate with bacterial meningitis outbreaks across 6,350 African districts. The results confirm that low rainfall, high dust (aerosol optical depth), and specific humidity patterns strongly correlate with outbreak probability?particularly in the Sahel region. Importantly, the study suggests a possible south-westward expansion of the meningitis belt into countries like Angola, Gabon, and the Republic of Congo, though findings are tempered by surveillance and lab confirmation gaps. The model achieved high sensitivity (84.3%) and specificity (81.0%) and provides an updated spatial risk map to support regional early warning systems and epidemic preparedness.