Examining the relationship between infectious diseases and flooding in Europe: A systematic literature review and summary of possible public health interventions

Brown, Lisa; Murray, Virginia

This work was carried out within Public Health England's department of Extreme Events and Health Protection, funded partly by the EU project "Public Health Adaptation Strategies Europe, the body of information still remains fragmentary. Many studies attempted to collect data retrospectively, had methodological shortcomings, lacked longitudinal data/baseline health data, control groups for comparison, and measures of clear disease outcomes. The studies included in this review were mainly observational studies with widely varying quality levels and study designs. Because it is unethical to conduct experimental studies on this topic, rigorous observational studies must be continue to be undertaken. Observational studies can present particular challenges because of the unpredictability of the timing and location of floods. Reporting and recall bias was very likely in many studies. Additionally, many studies relied on data from disease surveillance systems. Obtaining relevant disease surveillance data pre-, mid-, and post-flooding is frequently challenging. Population displacement can distort the rates of comparison for infectious disease incidence. The quality and robustness of disease surveillance systems can vary from country to country, and a country with a weak disease surveillance system will probably lack pre-flood baseline data. Flood damage to pre-existing public health infrastructure can exacerbate weaknesses in a disease surveillance system. Furthermore, it is difficult to attribute an increase in infectious disease incidence solely to a flood event, and therefore this issue may be under-investigated and under-reported. Finally, this systematic review is not entirely exhaustive, and there may be many other reports in gray literature, but the quality is likely to be lower than the peer-reviewed published reports identified.