Systemic and Institutional Determinants of Cholera Transmission and Control in the Rohingya Refugee Camps, Cox’s Bazar, Bangladesh

Abstract

Cholera has persisted and periodically surged in the Rohingya refugee camps of Cox’s Bazar, Bangladesh, despite sustained humanitarian investment, raising questions about the systemic factors that mitigate or enhance transmission. This study characterised the institutional and infrastructural determinants of cholera transmission and control through a synthesis of surveillance and programmatic data and a documentary review of the response architecture, 2018 – 2026. A multi-layered surveillance system combining community-based surveillance, indicator-based syndromic surveillance, sentinel rapid testing and laboratory confirmation underpinned outbreak detection. The syndromic burden of acute watery diarrhoea declined steadily, from approximately 231,000 cases in 2018 to approximately 122,000 in 2025, reflecting maturing water, sanitation and hygiene services. Culture-confirmed cholera nonetheless remained endemic with recurrent upsurges, the largest in 2024 (534 cases), demonstrating that infrastructural investment alone is insufficient. Rapid diagnostic test – positive counts exceeded but tracked culture-confirmed counts, indicating substantial laboratory confirmation capacity. Integrated reactive oral cholera vaccination, with coverage exceeding 90% in the 2025 campaign, was associated with rapid outbreak suppression. Persistent transmission was attributed to the fragility of water, sanitation, and hygiene gains against monsoon damage, residual point-of-use and foodborne pathways, a predominantly reactive posture, and funding volatility in a protracted crisis. The findings support a shift towards anticipatory, spatially and temporally targeted, integrated control, including environmental surveillance and preventive vaccination, sustained by predictable multi-year financing and strengthened health and water-sector coordination.