Flooding and the Threat of Infectious Disease

Recent flooding in Boznia-Herzegovina have put thousands at risk. (Photo: ELVIS BARUKCIC AFP/Getty Images)
Recent flooding in Boznia-Herzegovina has put thousands at risk. (Photo: ELVIS BARUKCIC AFP/Getty Images)

Of all the natural disasters, flooding is both the most common and the most likely to affect developed and developing countries alike. Flooding poses significant health risks to the populations it impacts in both direct and indirect ways. While the greatest and most direct risk of injury occurs during the flood itself, where deaths from drowning, electrocution, or collapsing structures account for the majority of flood-related mortality, floods can also increase the transmission of water-borne and vector-borne diseases such as malaria, dengue fever, cholera and hepatitis A.


According to the World Health Organization, the most severe health risk associated with flooding is the contamination of water sources, leading to an increased risk of infection of water-borne diseases through direct contact or the ingestion of polluted waters. Diarrhea and leptospirosis, a bacterial disease that transmits through contact with water or damp surfaces, have been common in the aftermath of floods, from Russia and India to Nicaragua and the United States. Vector-borne illnesses are also a serious health risk associated with major floods and monsoons. Standing water can act as a breeding site for mosquitoes and expose humans to a heightened risk of infection of diseases such as malaria and West Nile Fever.


While developed and developing countries have an equal probability of being struck by natural disasters, limited-resources countries are often less able to cope with disease outbreaks, particularly as response systems are disrupted during flooding periods. Low-income urban regions are highly susceptible to the spread of infectious diseases due to overcrowding, poor existing health conditions, and inadequate health infrastructure. To compound the problem, mass flooding and monsoons have intensified over the past several decades as a result of rising global temperatures. Climate change contributes to both the frequency and the intensity of heavy rains, heat waves, and rising sea levels, all of which accelerate the transmission of communicable diseases.


This past week, the Balkan region has been inundated with the worst floods in over 100 years. So damaging were the floods, in fact, that Bosnia’s Foreign Minister compared the destruction to that of the country’s wars in the early 1990s. While the worst of the waters appears to be over, focus is now shifting to the imminent, and almost inevitable outbreak of disease. Contaminated water has covered entire towns, increasing the risk of water-borne diseases. This creates an ideal environment for vectors to thrive. As some of the poorest nations in Europe, the Balkan states are ill-equipped to handle such a major public health disaster. Southeast Asia is another part of the world prone to the damages caused by monsoons and regular outbreaks of disease, particularly in the summer months. As this region prepares for the floods, special attention is given to ensure that local hospitals have the capacity and the stock of medicine available to treat patients quickly and on a large scale.


Floods, heavy rains, and monsoons are formidable forces of nature which cannot be stopped or contained. However, the control of disease resulting from these natural disasters is possible, provided that the resources are made available to experienced local, regional, and international agencies. It is the responsibility of global citizens to tackle these disasters from all angles, and to ensure that infectious diseases do not wreak havoc on the populations of affected areas.

-Sarah Vassallo; Grants Officer


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