Background – University of Copenhagen

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Copenhagen Center for Disaster Research > Projects > Combating Cholera > Background

Background

Source: UNICEF 2010 / Ahsan Khan

Since John Snow discovered that the Broad Street pump was responsible for the London cholera outbreak in 1855, scholars have searched for associations between contaminated drinking water and cholera cases. While other studies have shown the role of hygiene, sanitation, population density and food in the spread of cholera, the main focus remains on primary transmission through drinking water.

However, the possible association between cholera and water quantity is still unknown. Given current climate change projections of more severe droughts and floods, water stress in expected to increase in Bangladesh. Therefore, it is essential to understand what kind of an effect water stress will have on cholera prevalence.

The idea for this study originates in Pakistan where Jensen et al. showed that diarrhea prevalence is significantly more related to water quantity than water quality. Furthermore, E. coli counts (water quality indicator for fecal contamination) in drinking and domestic water have an insignificant association to diarrheal prevalence unless a household is using approximately 100 liters per person per day – a quantity similar to the average in developed nations.

Water conditions in Bangladesh:

Bangladesh is expected to be one of the countries most affected by climate change due to multiple climate related hazards: increasing sea level, as well as increased inlands floods, droughts and cyclones.

The country already suffers from annual floods and droughts that affect up to 70% of the country and cause countrywide water stress. This situation of biannual water stress is expected to be even further intensified by India’s political decisions to dam and hereby control the water flow of the three major rivers feeding into the country.

For Bangladesh’s 160 million people, of whom many are surviving for less than a dollar per day, the household water availability is not only a human right in itself but also a crucial element in combating life threatening infectious diseases. One such disease is cholera – one of the most studied deadly diseases that is native to Bangladesh.

Cholera:

Cholera is a life-threatening diarrheal disease. The Vibrio cholerae (V. cholerae) bacteria that causes cholera will survive whenever the human environment is degraded by poverty and overcrowding and when population is displaced by disasters and conflicts. The complex patterns of human behavior and its interaction with ecological and biological characteristics of V. cholerae that foster the transmission of the disease will continue to make cholera a global public health challenge for the twenty-first century.