Cholera often breaks out when there is overcrowding and inadequate access to clean water, rubbish collection and proper toilets.
It causes profuse diarrhoea and vomiting which can lead to death by intense dehydration, sometimes within a matter of hours.
Cholera is a serious risk in the aftermath of emergencies, like the Haiti earthquake of 2010, but can strike anywhere. The situation can be especially problematic in rainy seasons when houses and latrines flood and contaminated water collects in stagnant pools.
According to the World Health Organisation (WHO), cholera affects three to five million people worldwide and causes between 100,000 and 130,000 deaths per year.
MSF’s water and sanitation engineers and logisticians play a vital role in the prevention of cholera. The disease is treatable and, in many situations, MSF teams have limited the death rate to less than one percent.
Hover over the image below for an interactive guide to cholera
What causes cholera?
Cholera is caused by an infection of the intestine with the bacterium Vibrio cholerae. The bacterium causes the cells lining the intestine to produce large amounts of fluid, leading to profuse diarrhoea and vomiting.
The infection spreads when someone ingests food or water contaminated with the faeces or vomit of someone carrying the disease.
Contaminated food or water supplies can cause massive outbreaks in a short period of time, particularly in overcrowded areas such as slums or refugee camps.
Symptoms of cholera
Typically, symptoms of cholera appear within two to three days of infection. However, it can take anywhere from a few hours to five days or longer for symptoms to appear.
Cholera can be diagnosed by examining stool samples or rectal swabs but, due to the fast-acting nature of the disease there is often little time to do so.
In epidemic situations, a diagnosis is often made by taking a patient history and conducting a brief examination, with treatment given before there is time for a laboratory to confirm the diagnosis.
Cholera can be treated simply and successfully by immediately replacing the fluids and salts lost through vomiting and diarrhoea – with prompt rehydration, less than one per cent of cholera patients die.
Cholera victims are always treated with oral rehydration solutions - prepackaged mixtures of sugars and salts that are mixed with water and drunk in large amounts. Severe cases will need these fluids to be replaced intravenously via a drip, and antibiotics are sometimes administered.
MSF treated 32,600 people for cholera in 2015.