The Temporal and Spatial Patterns of Cholera Outbreaks in the Rohingya Refugee Camps, Cox’s Bazar, Bangladesh
Abstract:
Cholera remains a major public health threat in humanitarian settings such as the Rohingya refugee camps of Cox’s Bazar, Bangladesh, which are characterised by congestion, inadequate water and sanitation, and overstretched health services. This study analysed the temporal and spatial patterns of cholera in the camps to identify seasonal variation and distribution across camps and to inform control. We used secondary data from the World Health Organization’s Early Warning, Alert and Response System (EWARS), sentinel surveillance, and laboratory surveillance to construct annual weekly trend lines and epidemic curves for acute watery diarrhoea and culture-confirmed cholera, and to map case distribution across the 33 camps from 2018 to 2026. Syndromic surveillance showed year-round acute watery diarrhoea transmission with multiple non-stable seasonal peaks and a steady decline over seven years, from about 231,000 cases in 2018 to about 122,000 in 2025. Laboratory surveillance indicated that cholera was endemic, characterized by recurrent upsurges; the largest outbreak occurred in 2024 with 534 culture-confirmed cases. The dominant cholera peak occurred in the post-monsoon period (mid-September to December), diverging from the April–June pre-monsoon peak historically reported for south-eastern Bangladesh. Transmission was largely sporadic across camps without persistent hotspots, except during the 2021 and 2024 outbreaks, and shifted over time from early Teknaf-based coastal camps to the densely populated inland-located Ukhiya-based camps. These findings indicate a need to update earlier seasonality evidence and to target preventive water, sanitation, hygiene and vaccination interventions to the post-monsoon period and the high-density Ukhiya camps.References:
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