Page last reviewed: 13/07/2011

Cholera is a bacterial infection. It is caused by drinking water that is contaminated with vibrio cholerae bacteria, or by eating food that has been in contact with contaminated water.

Many people who are infected with cholera bacteria do not develop any symptoms. However, cholera can cause:

  • severe, watery diarrhoea
  • nausea
  • vomiting
  • muscle cramps

Without prompt treatment, about half of people with the most severe symptoms will die within a few hours, usually due to a combination of dehydration and shock (a sudden and massive drop in blood pressure that starves the body of oxygen).

If cholera is promptly treated with a combination of antibiotics, fluids and oral rehydration solution, the outlook is much better: only 1% of people will die from the disease.

How cholera is spread

Around three-quarters of people who are exposed to cholera bacteria do not develop any symptoms. However, these people can contaminate water by passing stools (faeces) that contain bacteria into water, or pass on the disease through poor food hygiene. 

How common is it?

Because of the improvements in sanitation and water hygiene over the last 100 years or so, cholera has been wiped out in Ireland and much of the rest of the world.

All reported cases of cholera in Ireland are as a result of people catching the infection while travelling abroad.

Cases of cholera are now largely confined to regions of the world with poor sanitation and water hygiene, such as:

  • sub-Saharan Africa (all the countries south of the Sahara desert)
  • south and south-east Asia, particularly India and Bangladesh
  • some parts of the Middle East
  • some parts of South America

Even in these parts of the world, cholera remains relatively uncommon. However, mass outbreaks can occur in times of natural disaster, war or civil strife, due to overcrowding of people in poor living conditions, and lack of access to clean water.

For example, outbreaks of cholera occurred in some parts of Iraq in 2008, and in a number of refugee camps in Zimbabwe in 2009.

Advice for travellers

If you are travelling to parts of the world known to be affected by cholera, following some basic precautions should prevent you from contracting a cholera infection:

  • maintain good personal hygiene
  • only drink water from a bottle that has been properly sealed or carbonated
  • do not buy ice cream, ice cubes or fruit juices from street vendors
  • do not eat raw vegetables, peeled fruit, shellfish or salads


There is a vaccine (given as a drink) that protects against cholera. It is estimated to be 85% effective.

Vaccination is usually only required for:

  • people travelling in remote areas where cholera epidemics are occurring and there is limited access to medical care
  • those intending to visit high-risk areas such as refugee camps or war zones
  • those taking part in disaster relief operations

These people include emergency relief workers, members of the armed forces and healthcare workers.

It is important to get advice from your nurse or doctor about whether you need a cholera vaccination well in advance of travelling.


Cholera needs prompt treatment with oral rehydration solution (ORS) to prevent dehydration and shock. ORS comes in a sachet. It is made up of a mixture of salts and glucose, which are dissolved in water. ORS is ideal for replacing the fluids and minerals that are lost when a person becomes dehydrated.

As well as treating dehydration and shock with ORS, antibiotics can be used to treat the underlying infection.

ORS sachets are available from many pharmacists, camping shops and travel clinics. If you are travelling to regions of the world affected by cholera, take ORS sachets as a precaution.

Cholera is a notifiable disease in Ireland.  Further information on cholera is available on the website of the Health Protection Surveillance Centre at

Content provided by NHS Choices and adapted for Ireland by the Health A-Z.

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