Fighting Cholera with One Hand While Helping It with the Other

2011-07-15 | |
Last updated: 2011-07-15

Why are Cholera Epidemics Becoming More Common?

Global Warming Increasing Cholera Rates

One of the causes for the increase in Cholera infections is likely as a result of global warming. Now, while it may seem difficult to believe that changes in weather can increase rates of infection, the science does support this argument.

Research from International Vaccine Institute studying Cholera rates and the relationship to the weather found some important results. With respect to temperature, they found that a 1 degree Celsius increase in temperature resulted in double the number of Cholera cases within 4 months. They also found that an increase of 200-millimers of precipitation within a month would lead to almost double the number of Cholera cases within 2 months. The Cholera outbreak that hit Cameroon last month following heavy rains also supports these observations.

Changes to the Natural Environment Causing Cholera Rate Increases

In addition to global warming as a contributor to increases in Cholera rates, other man-made causes are increasing the rates of Cholera infection. Research from the University of North Carolina attempted to create a model linking changes in water flow to the number of people affected by Cholera. Based on the predictive model created using actual measurements, the researchers were able to determine that people living in areas where water levels were controlled against flooding were more likely to develop cholera.

This means that as water flows become more controlled or rivers are damned, people living in the area will face cholera more often.

Overpopulation and Lack of Infrastructure Increasing Cholera Rates

Environmental changes are not the only contributors to rising rates of Cholera infection, however. According to the United Nations agency for human settlement, UN-HABITAT, some African cities will grow by as much as 85% in the next 15 years, most growing while experiencing a severe shortage of housing and basic infrastructure including water and sewage services. The resulting growth is expected to follow the current trend with 70% of the population living in slums.

In Asia, the number of people in slums will also rise. By 2025, it is expected that 50% of the population will live in megacities containing massive slums. Those in the Asian slums will also have little access to sanitation. Worldwide, there are 2.6 billion people lacking access to basic sanitation.

Predictably, this growth in slum dwellers is very bad news for the rate of growth of Cholera infections. According to a 2010 study from Harvard University looking at one such African city, the researchers found a relationship between the number of people lacking basic sanitation and the rates of Cholera.

Specifically, they found that for every percent increase in the number of people living without basic plumbing services, the rate of Cholera infection also rose by almost a percent. Worse still, the research found that as the population density increased, for every additional 1000 persons per square kilometer, the rate of Cholera increased by 2%.


While Cholera is a natural phenomenon, the rate to which it affects the population can be affected significantly by human activities. Because of this, its important to look at more than simply vaccinating the population. With cholera vaccines only offering short term immunity to the condition, it is far more important to reduce the conditions that allow cholera to flourish in the first place. At a minimum, this means providing people with basic sanitation facilities.

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Category: Disease Information, Disease Prevention, Health Risks

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