Investigating well water contamination: A key contributor to cholera outbreaks Costa Matyavira

Costa Matyavira

According to UNICEF Sudan, cholera is a highly infectious disease that is caused by eating food or using water contaminated with the bacterium vibrio cholerae and is an easily treatable diarrhoeal disease. The World Health Organization (WHO), also insists that cholera transmission is closely linked to inadequate access to clean water and sanitation facilities.

Contaminated water sources are a major contributor of cholera outbreaks and waterborne diseases such as typhoid fever, dysentery, hepatitis A and polio around the globe especially in developing countries such as Zimbabwe, Zambia and Malawi.

Below is evidence of photos of wells taken in Zimbabwe recently. The pictures are a clear evidence that wells whether deep or shallow if not properly constructed and managed can be a major source of cholera and other disease outbreaks. The following factors can propagate spread of cholera.


Slab structure


Taking a closer look on the above pictures concrete slabs covering the wells are thin, they are less than 20cm thick. It is clear that if there is flooding due to rainfall, runoff enters directly into the wells. Runoff can be mixed with raw sewage causing well water contamination.  It is obvious that people will drink or use the contaminated water to wash their hands.

Another problem is water penetration. Sandwich like concrete slabs such as shown above promote direct runoff penetration into wells. They are not built from underground. A gap that exist between the slab and the ground causes running water to force its way through that gap even if the rainfall is light. No matter how shallow or deep that well is, if there is that mentioned gap, dirty water enters into the well.


Wells without lids

Some wells are left open as in the above. In the rain season running water that is contaminated can enter in wells without lids. People who are not responsible can relieve themselves in open wells.  Human waste might contain the bacteria that causes cholera and water borne diseases.

A further analysis of the pictures indicate that the water sources are surrounded by a ridge of soil. This is common in dug wells. The disadvantage is that whether the well is deep or shallow it will be positioned in a depression and this speed up flooding around the well if it’s raining causing well water contamination,

Holes and cracks


The pictures above show wells that have holes and cracks around them. These are entrance points for contaminated water flowing on the ground.  They can also be habitats for mosquitoes, frogs and snakes. Mosquitoes can breed in those holes and this can also lead to malaria outbreaks.



 Grass and Debris around the wells

People tend to ignore grass growing around the wells. That grass traps a lot of run off promoting seepage into the well. Water seeping into the well might be contaminated resulting in cholera outbreaks. Furthermore that grass can be a habitat of mosquitoes, snakes and frogs that can enter a well and infect the water. Some reptiles can even die inside the wells polluting the water source.

Minimising the risk


Wells such as the ones below can minimise the risk of water contamination by the bacteria that causes cholera and other infectious diseases.



The concrete slab is elevated to prevent runoff entering into the well during flooding. There are no holes, cracks and any green or dry grass around the well so contaminated water cannot easily penetrate or seep into the well. Such wells break the vibrio cholera life cycle leading to a reduction of cholera, malaria and waterborne disease outbreaks.

However there are more advanced ways of providing safe water to the public. The researcher focused on the most common type of wells in use around Zimbabwe and other African countries. These type of wells provide safe water if they are well managed except in water logged areas. The health officials should educate the public on the importance of clean water sources to contain cholera outbreaks. They should recommend construction of modern wells.










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