Health Effects of Hurricane and Flooding

Heavy rain during storm, hurricane or typhoon pours huge amount of water on land. During last 3 decades since 1996 overall 39 hurricane landed over east coast of United States, to include state of Alabama, Florida, Georgia, North Carolina, South Carolina, New York and Texas. Thirteen Hurricane landed over Florida and 12 over Louisiana. In U.S. history, the most financial losses and health problems were observed following Hurricane Katrina, which had spread in state of Louisiana, Florida, Texas and Mississippi. The Hurricane Harvey poured 51.8 inches of rain in Huston and surrounding town in Texas.

Flooding results in huge financial losses and major health issues. The repair and reconstruction cost after devastation following Hurricane Katrina was over 100 billion dollars. The structural damages caused by hurricane Harvey were far worse than Hurricane Katrina and cost to rebuild affected cities and town could be over 160 billion dollars. The property damages, stoppage of industries and restricted transport system causes loss of job and income.

The cost of health management post hurricane is also additional expenses. The most common medical problem observed in the past 3 decades following flooding in North America due to hurricanes were personal injuries, mental issues, diarrhea and upper respiratory tract infection. The flooding as observed following hurricane Harvey can create major health issues on top of structural damages of roads, bridges, sewer system, residential and commercial properties.

Flooding occurs when rain water is far more in volume than the capacity of sewer drainage system to remove the water. Excess water over the land initially soaks into the ground or passes through sewer system in to sea or river in most urban and rural areas. Once the ground is saturated and sewer system is flooded with water then the storm water or runoff water starts collecting over the ground. The level of water over the ground increases if volume of water falling by rain is much higher in volume than the water drained by sewer system. Collection of stagnant water over the land is known as flooding. Flooding is observed when the volume of rainfall is much higher as seen following Hurricane of category 2 or higher as in case of hurricane Katrina and hurricane Harvey. The drainage of water from sewer system is often restricted when level of sea or river is higher than the water level over the land. The restriction of water flow in to river or sea is further slowed down because of large volume of derbies blocking the sewer system. Once rain stops, the water is drained out in few hours or days if drainage system is efficient and not blocked. The water level may remain high for several days if drainage pipes are inefficient because of debris covering the lumen and stuck to wall of the drainage system. The repair workers and technicians in most cases are often unable to locate the area of blockade for several hours or days. The diseases are less wide spread if flood water is drained out in 3 to 4 days once the rain stops. In USA the increase number of cases of diarrhea and respiratory infection were observed following prolonged flooding as in Louisiana after Hurricane Katrina and New York after hurricane Sandy.

The epidemic health problems are the major issues following flooding in tropical and subtropical areas. The mosquito carrying viral and protozoal infection become epidemic diseases in tropical countries following flooding. The endemic diseases in tropical as well as subtropical areas like malaria, zika virus infection, dengue fever, viral hemorrhagic fever, yellow fever and leishmaniasis spreads as an epidemic disease following floods as mosquito population increases. The communicable diseases are often seen in area where sanitation is of lower quality and population is dense resulting in crowding of houses. In USA the diseases that are carried by mosquitoes are rare and eradicated, thus epidemics of mosquito or tick carrying diseases were not observed during last 3 decades following hurricane and flooding. The most common health issues observed following previous hurricane in USA were personal injuries, mental illnesses, upper respiratory illnesses and few cases of diarrhea. The minor increase number of zika virus was observed in Florida and Louisiana after hurricane Katrina. The personal injuries in most cases are drowning, crush injuries and blunt trauma. Spread of communicable diseases are not observed following past flooding in USA. The waterborne diseases like diarrhea and upper respiratory tract infection were observed following previous flooding in USA. The published studies also suggest the mosquito breeding was observed over pocket of water left after flooding is drained. The breeding includes Culex mosquitoes and Aedes mosquitoes. Culex mosquitoes carry West Nile, as well as St. Louis encephalitis and Japanese encephalitis. Aedes aegypti are the primary carriers for Zika, as well as dengue, chikungunya, and yellow fever. In USA during last 3 decades following several hurricanes epidemics of vector borne diseases were not recorded, though increased number of vector were observed. In few cases delayed increase in number of West Nile diseases were observed in areas affected by Katrina. Nuisance mosquitoes observed in Texas during transmission season were not found to carry any viruses or protozoa.

The human and animal discharges consisting viruses, bacteria and protozoa lies on dry ground in inactive dormant stage. The viruses, bacteria and parasites rapidly multiples in flooded water resulting in contamination of flood water. Stagnant flood water over the street and land causes rapid mixing of debris, soil, feces and urine. The flood water also mixes with solid content of sewer system. The soil and content of sewer system carries expectorant, sputum, feces, urine and purulent discharges which may be mixed with viruses, bacteria and protozoa from infected individual. Flood water may also mix with content of sewer treatment plant, which may also contain viruses, bacteria and parasites. The contaminated flood water eventually is discharged into river and sea. The efficient drainage system removes the contaminated water once the rain stops. Once the flood water level is removed then the pocket of water over the land may become a breeding ground for mosquitoes and ticks. Since the mosquito transmitted diseases are extremely rare in USA, the increased number of mosquitoes may not reflect increase number of vector borne diseases. The only health issue predominantly observed following flooding in USA were injuries, diarrhea, respiratory illnesses and psychological illnesses. Psychological illnesses observed after hurricanes were depression, anxiety, increased cases of substance abuse1 and sleep deprivation because of financial crisis. In few countries, mold exposure were increased resulting in increased upper respiratory symptoms.²

The study published by Rhodes J. in Journal of American Academy of Nurse Practitioner has shown increased cases of Vibrio Vulnificus bacterial infection following Hurricane Katrina.³

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