Cholera: the deadly disease explained

Last updated 29 May 2025

Cholera is still a real health threat across the world, especially after disasters. British Red Cross health adviser Greg Rose explains the threat still posed by this potentially deadly disease.

What is cholera?

Cholera is a bacterial infection that's spread when people consume contaminated food or water – it is nearly always waterborne. The infection causes an acute diarrhoeal illness, which is usually mild but can develop into life-threatening symptoms.

Cholera is typically most prevalent in communities with poor infrastructure or during humanitarian emergencies, such as earthquakes, where there is a lack of clean water, poor hygiene and limited access to healthcare. It's most common in sub-Saharan Africa, Central America, the Caribbean, South Asia and parts of South-East Asia.

In May 2025, health officials in Sudan warned that the country was facing a major health disaster after over 100 people died of cholera in less than a week. 

This waterborne disease is preventable and treatable. However, without treatment death can occur within hours.

How is cholera spread?

Typically, cholera is spread through the consumption of food or water contaminated with the bacteria, Vibrio cholerae. Usually, in an epidemic, it’s the faeces of an infected person that contaminates the food or water.

This means the disease can spread rapidly in areas without adequate water treatment, facilities or hygiene. Very rarely, cholera is spread directly from contact with an infected person.

What are the symptoms of cholera?

Cholera symptoms can range from mild to life-threatening. Most people have mild or no symptoms. Those who do develop symptoms will usually experience:

• severe, watery diarrhoea
• stomach and/or leg cramps
• vomiting
• intense thirst
• restlessness or irritability

 

However, the above are just mild symptoms of cholera. You also need to be aware of signs of dehydration, especially when someone is experiencing severe, watery diarrhoea, including:

• rapid heart rate
• low blood pressure
• loss of skin elasticity
• dry mucous membranes

Those who experience severe and possibly fatal cholera disease will often suffer from kidney failure. This can result in shock, coma and death within hours.

Cholera has a short incubation period, between two hours and five days, before symptoms begin. This, and the common water source and so often simultaneous infection, explain why you often see a sudden burst of cases.

It’s important to note that even if people do not display symptoms, the bacterium, Vibrio cholerae, stays in their faeces for up to two weeks. So if people are practising open defecation (associated with poor hand washing or water course contamination and transmission by flies), or if infrastructure is damaged after a natural disaster, then you can see how a cholera outbreak can occur.

Can cholera be treated?

Cholera is highly treatable. If cholera is detected early, then the patient may just need oral rehydration solution to prevent dehydration. If it’s more serious, then the patient may require fluid replacement at hospital. It’s not the bacterium that will kill a person.

A combination of acute diarrhoea and vomiting can lead to severe dehydration – a victim can lose several litres of fluid in a matter of hours. This is what proves fatal. While the treatment of cholera is relatively simple, the issue is that in places where cholera is prevalent, such as in Yemen and sub-Saharan Africa, health care is not always readily available.

This can result in a lot of unnecessary deaths from this treatable waterborne disease.

Does the Red Cross help treat cholera?

Teams from across the Red Cross and Red Crescent Movement treat people with cholera through mobile health clinics after a disaster, providing rehydration and saving lives. This has been the case in Syria, Yemen and Pakistan after the 2022 floods.

Red Cross and Red Crescent teams also focus on healthcare and prevention, providing access to clean water and hygiene products to stop cases spreading.

How do you prevent cholera?

The most effective cholera prevention solution in the aftermath of a disaster is to make sure people are aware of the dangers and have access to clean, chlorinated water, soap and toilets. The main causes of cholera are contaminated water or food, so maintaining personal hygiene and access to uncontaminated food and water is paramount.

Why is a cholera outbreak so common after a conflict or natural disaster?

In Yemen, for example, conflict has destroyed essential infrastructure, and poor conditions mean that cholera has taken hold. The country suffered an unprecedented cholera outbreak in 2016, and it has become the largest and fastest-spreading epidemic since the World Health Organisation began recording outbreaks in 1949.

After the cholera outbreak peaked in 2017, a second wave of cases began in August 2018 and now continues to affect the lives of millions. Elsewhere, a cyclone devastated homes and facilities in Mozambique. Water and sanitation no long function in many cities. Conditions then become ripe for waterborne diseases like cholera.