Date of Award

January 2025

Document Type

Open Access Thesis

Degree Name

Master of Public Health (MPH)

Department

School of Public Health

First Advisor

Kaveh Khoshnood

Second Advisor

Brian Wahl

Abstract

Cholera outbreaks are complex and driven by an interaction of environmental circumstances and conflict-related disruptions, yet few studies have integrated both in the context of conflict regions. This ecological study examines cholera transmission dynamics in Sudan from 2016 to 2025, exploring temporal associations using cross-correlation analysis and applying generalized additive mixed models (GAMMs) to analyze the influence of remotely sensed environmental variables (rainfall, temperature, NDVI, NDWI) and conflict indicators (civilian targeting, political violence, demonstrations) on cholera cases. Weekly cholera surveillance data, combined with satellite-derived environmental variables and conflict event datasets, were modeled across two time periods: pre-conflict (2016-2018) and active conflict (2023-2025). Findings reveal that vegetation density (NDVI) was a consistent environmental driver of cholera across both pre-conflict and conflict periods. Associations between environmental factors and cholera strengthened during conflict, likely due to the collapse of WASH infrastructure increasing population vulnerability to climate shifts. Rainfall showed mixed and modest effects across models and became more pronounced when conflict factors were included. Nighttime temperatures were positively associated with cholera risk, reflecting bacterial survival in warmer conditions, while lower surface water availability (NDWI) was associated with higher cholera cases, potentially due to reliance on other unsafe water sources. Conflict-related variables, particularly civilian targeting and demonstration events during Period 2, were strongly associated with increased cholera risk. Spatial analyses reveal that reporting gaps overlap with conflict-affected regions, suggesting that true cholera burden is significantly underestimated. Together, these findings show the importance of integrating remote sensing and conflict event data into cholera surveillance frameworks. This highlights the critical role of environmental monitoring in strengthening early warning systems when traditional surveillance is disrupted by violence.

Comments

This is an Open Access Thesis.

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