Balaji Ramesh

and 6 more

Purpose:Flooding following heavy rains precipitated by hurricanes/tropical storms has previously been shown to increase fecal-oral diseases, vector-borne disease transmission and pregnancy complications during or following inundation. Remote sensing can be used to spatio-temporally resolve inundation extents for subsequent analysis of risks associated with flooding at a finer scale. Here we combined earth observations of the flooding caused by Hurricane Harvey in 2017 with Emergency Department (ED) visit data to evaluate health outcomes associated with flooding.Methods:Our study area included 1073 flooded and 1809 non-flooded census tracts in Texas which were categorized using the inundation maps from Dartmouth Flood Observatory. These maps were created using Sentinel and MODIS satellite imagery captured between 28th Aug - 4th Sep 2017 following the landfall of the hurricane. ED visits in the study area were obtained from Texas Department of State Health Services. A controlled interrupted time series design was employed using ED visits from non-flooded tracts as the control series and ED visits before a week of the landfall and through 2018 as control period. Poisson regression using generalized estimating equation with census tracts as the group variable was used to estimate the relative risk of the health outcomes associated with flooding during and following the flooded days, adjusting for the age, ethnicity, race, sex of the patient, day of week, month and year trends. Results:Flooding was associated with a 35% (95% CI: 22%-48%) increase in risk for insect stings and 24% (17%-31%) increase in risk of pregnancy complications during the flood period. Similarly, relative risks were also elevated (>1) for drowning, hypothermia, and intestinal infectious diseases in the flooded tracts. Also, in the months following the flood period, the relative risk was still elevated (>1) for pregnancy complications and insect stings while asthma and acute respiratory infections showed decreased risks. Conclusion: Earth observations have helped in understanding the health risks that are related to flooding. These earth observations can in turn be used to identify specific communities with increased health risks during and following flooding events.