It Will Flood Again: Infectious Disease Lessons from the 2025 Hat Yai Flood: A Narrative Review
Abstract
loods are among the most frequent natural disasters globally and are recognized as drivers of infectious disease outbreaks. Knowledge of local endemic disease patterns may help anticipate post-flood risks. This narrative review examines how flooding may amplify these risks, drawing on the 2025 Hat Yai flood to identify clinical and public health preparedness priorities.
Potential mechanisms include pathogen mobilization, vector breeding, host susceptibility, and healthcare system disruption. During the 2025 flood, approximately 1,300 millimetres of rainfall were recorded, with floodwaters peaking between 22 and 25 November. Five of six major hospitals became inoperable, leaving Songklanagarind Hospital as the sole functioning facility for over 700,000 people. Routine surveillance data are presented descriptively. Reported leptospirosis cases peaked one to two weeks after the flood, while dengue, melioidosis, and diarrheal disease showed differing temporal patterns. Higher rates of carbapenem-resistant organism detection and central line-associated bloodstream infection were reported in November and December than in the preceding months, coinciding with staffing shortages, intensive care unit (ICU) expansion, and increased patient transfers. However, these temporal patterns do not establish causation. Surveillance disruption may have affected reporting completeness and accuracy, limiting interpretation.
Preparedness priorities informed by local endemic disease patterns include maintaining clinical awareness of flood-associated infections, preventing healthcare-associated infections, establishing contingency plans for healthcare disruption, and strengthening surveillance through automation. The 2025 Hat Yai experience underscores the need to integrate these priorities into preparedness for future floods.
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