Association of natural flood disasters with infectious diseases in 168 countries and territories from 1990 to 2019: A worldwide observational study

Background: Natural flood disasters have a devastating effect on society, but the comprehensive assessment of their association with infectious diseases is lacking. We aimed to comprehensively assess the association of natural flood disasters with new cases and deaths of different infectious disease globally from 1990 to 2019, and provide scientific evidence for early warning and measures for the prevention and control of outbreaks and endemic of potential infectious disease following natural flood disasters. Methods: We used data on natural flood disasters from international disaster database from 1990 to 2019. Data on infectious diseases were from the Global Burden of Disease Study 2019. Quasi-Poisson generalized linear models (quasi-Poisson GLM) were used to calculate the effects size, after controlling other confounders. Results: From 1990 to 2019, natural flood disasters occurred on 47,368 cumulative days in 168 countries and territories, resulting in a total of 242,516 deaths and affecting 3.55 billion people. The duration of floods showed a trend of increase, with an average increased rate of 5.14% per year (Estimated annual percentage change [EAPC] =5.14%, 95% CI: 3.57%-7.16%; p < 0.05). The incidence rates of most infectious diseases showed decreasing trends in the past 30 years (all p < 0.05), except for dengue (with an EAPC of 1.06%, 95%CI: 0.90%-1.23%). In the multivariable models, increased number of new cases of acute hepatitis A, acute hepatitis E, dengue, malaria, measles, meningitis, typhoid and paratyphoid, tuberculosis, and upper respiratory infections were significantly correlated with the longer duration of floods (all p < 0.05). Increased lasting days of flooding were associated with increased number of deaths from lower respiratory tract infections (0.173%), measles (0.126%), typhoid and paratyphoid (0.043%), tetanus (0.245%), and tuberculosis (0.154%, all p < 0.05). Conclusions: Natural flood disasters were associated with increased new cases and deaths of enteric infections, neglected tropical diseases, and respiratory infections. Concerted efforts should be made to design better strategies for adaptation to prevent and control the outbreak of floods-related infectious disease and reduce their impact on health and life