Flood and Respiratory Health

"Floods are the most frequent natural disaster worldwide, yet their respiratory health consequences remain comparatively under-recognised. Unlike drowning and traumatic injury, many respiratory effects emerge after floodwaters recede and arise through multiple, interacting pathways. This presentation conceptualises flooding as a sequence of respiratory exposures involving contaminated floodwater, displacement and shelter crowding, water-damaged housing, restoration and cleanup work, and disruption of ongoing healthcare. Growing epidemiological evidence indicates that the respiratory burden may extend well beyond the emergency phase. In a recent study of more than 300 million hospitalisations across 747 communities in eight countries and territories, flood exposure was associated with a cumulative relative risk of 1.30 (95% CI 1.13–1.49) for respiratory hospitalisation, with a delayed, inverted U-shaped lag-response and increased risk persisting for up to 210 days. Following the 2011 Great East Japan earthquake and tsunami, pneumonia hospitalisations increased 5.7-fold, although only 3.6% of post-disaster pneumonia cases were associated with near-drowning. Shelter crowding further increased the incidence of acute respiratory infection. The recovery environment creates additional and potentially modifiable exposures. Flood-damaged housing is associated with persistent dampness and mould, while demolition and restoration work can generate substantial exposure to particulate matter, endotoxin, and fungal glucans. Flood-related infections also remain clinically relevant; historical Korean leptospirosis outbreaks following floods and heavy rainfall demonstrate the interaction between environmental exposure, agricultural work, and severe pulmonary manifestations. Importantly, effect estimates vary across settings, reflecting differences in flood characteristics, housing, population vulnerability, exposure assessment, healthcare access, and recovery conditions. Comparative evidence regarding the effectiveness of post-flood respiratory interventions remains limited. For the Asia-Pacific region, priorities include standardised flood-exposure assessment, longitudinal respiratory surveillance, evaluation of housing and bioaerosol exposures, protection of cleanup workers, continuity of chronic respiratory and tuberculosis care, and rigorous evaluation of preventive interventions. Respiratory health should therefore be incorporated into flood preparedness and recovery well beyond the immediate disaster response. Keywords: flooding; respiratory health; dampness and mould; occupational exposure; disaster preparedness; Asia-Pacific"