What are the diseases that spread during floods?


Climate change has the potential to influence the earth’s biological systems, however, its effects on human health are not well defined. Developing nations with limited resources are expected to face a host of health effects due to climate change, including vector-borne and water-borne diseases such as malaria, cholera, and dengue. Floods can potentially increase the transmission of the following communicable diseases: Water-borne diseases, such as typhoid fever, cholera, leptospirosis and hepatitis A. Also Vector-borne diseases, such as malaria, dengue and dengue hemorrhagic fever, yellow fever, and West Nile Fever and several risks that may be caused by corpses.

1.Water-borne diseases

Flooding is associated with an increased risk of infection, however this risk is low unless there is significant population displacement and/or water sources are compromised. There is an increased risk of infection of water-borne diseases contracted through direct contact with polluted waters, such as wound infections, dermatitis, conjunctivitis, and ear, nose and throat infections. However, these diseases are not epidemic-prone.

2.Vector-borne diseases

Floods may indirectly lead to an increase in vector-borne diseases through the expansion in the number and range of vector habitats. Standing water caused by heavy rainfall or overflow of rivers can act as breeding sites for mosquitoes, and therefore enhance the potential for exposure of the disaster-affected population and emergency workers to infections such as dengue, malaria and West Nile fever.

3.Risk posed by corpses

Contrary to common belief, there is no evidence that corpses pose a risk of disease “epidemics” after natural disasters. Most agents do not survive long in the human body after death (with the exception of HIV -which can be up to 6 days) and the source of acute infections is more likely to be the survivors.

  • Tuberculosis can be acquired if the bacillus is aerosolized (residual air in lungs exhaled, fluid from lungs spurted up through nose/ mouth during handling of the corpse).
  • Exposure to bloodborne viruses occurs due to direct contact with non-intact skin of blood or body fluid, injury from bone fragments and needles, or exposure to the mucous membranes from splashing of blood or body fluid.
  • Gastrointestinal infections are more common as dead bodies commonly leak faeces. Transmission occurs via the faeco-oral route through direct contact with the body and soiled clothes or contaminated vehicles or equipment. Dead bodies contaminating the water supply may also cause gastrointestinal infections.

India has already been witnessing outbreaks of epidemics like dengue, chikungunya, malaria, diarrhea, typhoid, leptospirosis, cholera, jaundice and viral fever during the floods for the last few years. While dengue, chikungunya, and malaria are caused by mosquitoes breeding in stagnated waters, diarrhea, cholera and jaundice are caused by consumption of contaminated water and unhygienic foods.