Abstract
In times of flood, frequent exposure to contaminated flood water may pose a risk of infectious diseases to residents in cities of developing countries with a high population density and poor sanitation. We quantitatively assessed the risk of illness caused by Escherichia coli via major routes of infection both in times of flood and in normal times in Hue, Vietnam, a typical city in a developing country. In normal times, the annual risk of illness was 0.026, which means 1 in 38 residents acquiring illness, at the highest estimate, and the intake of uncooked vegetables posed a higher risk (0.024) than the other assumed routes of infection. In times of flood, the risk of illness markedly increased to 0.45 owing to unsanitary activities during these times such as moving furniture, cleaning, cooking and playing. The risk attributed to flood, with a duration of only 6.5 days per year, was 17 times as high as the annual risk in normal times. This reveals that the risk of illness in this city is highly affected by periods of flooding and that flood prevention through infrastructural development is expected to contribute to a significant risk reduction. However, a more realistic approach to reducing risk would be to refrain from unsanitary activities in times of flood.
