Cholera is a potentially fatal bacterial infection caused by consuming contaminated food or water.
Not everyone who becomes infected will develop symptoms, but those who do will usually experience:
These symptoms generally develop within a few days of infection, although they can sometimes occur after just a few hours.
Without treatment, the combination of diarrhoea and vomiting can cause a person to quickly become dehydrated and go into shock (where there's a sudden massive drop in blood pressure). In the most severe cases, cholera can be fatal.
Cholera can spread if food and, in particular, water become contaminated with the stools of an infected person. This is why cholera is most widespread in regions of the world with poor sanitation, such as parts of:
- sub-Saharan Africa
- south and south-east Asia
- the Middle East
- central America and the Caribbean
Mass outbreaks of cholera often occur after natural disasters or during war, as a result of overcrowding in poor living conditions and a lack of access to clean water.
The World Health Organization estimates that there are 1.4 to 4.3 million cases of cholera worldwide every year. The condition is also responsible for many thousands of deaths.
There haven't been any cases of cholera originating in England and Wales for over 100 years, although travellers do occasionally bring the infection back with them. However, this is rare, with only six cases of cholera reported in England and Wales during 2013/14.
Advice for travellers
If you're travelling to parts of the world known to be affected by cholera, you should take some basic precautions to prevent a cholera infection and other causes of travellers' diarrhoea.
For example, you should:
- only drink water that's been recently boiled, or drink from a bottle that's been properly sealed
- avoid eating ice cream and don't have ice in your drinks
- avoid uncooked fruit and vegetables, unless you've washed them in safe water or peeled them yourself
- avoid shellfish, seafood and salads
Read more about food and water safety abroad.
Vaccination against cholera may sometimes be recommended if you're travelling to areas where the infection is widespread, particularly if you're an aid worker and likely to have limited access to medical services.
You should speak to a nurse or doctor about whether you need a cholera vaccination well in advance of travelling, if you're considering visiting an area affected by cholera.
The cholera vaccine is available as a drink, which is given in two or three separate doses that are taken one to six weeks apart.
The vaccine is estimated to be about 85% effective in the months after vaccination, although the level of protection gradually reduces over time and booster doses will eventually be needed if you continue to be at risk.
Read more about cholera vaccination.
Cholera can be easily treated using oral rehydration solution (ORS) to prevent dehydration and shock. ORS comes as a sachet containing a mixture of salts and glucose, which is dissolved in water. It's ideal for replacing the fluids and minerals that are lost when a person becomes dehydrated.
ORS sachets are available from pharmacists, camping shops and travel clinics. If you're travelling to regions of the world affected by cholera, you should take ORS sachets with you as a precaution.
When a person with cholera is very severely dehydrated, intravenous antibiotics may be recommended to shorten the duration of diarrhoea and speed up rehydration.
Read more about accessing healthcare abroad.
A vaccination is available to protect against cholera when travelling, although most people won't need it because food and water hygiene precautions are usually enough to prevent infection.
Vaccination is usually only recommended for travellers to areas where cholera is widespread, particularly for aid workers and people who are likely to have limited access to medical services.
The cholera vaccine is usually available on the NHS, but this can vary. It's also available through private prescription from a private travel clinic.
The cholera vaccine is given as a drink, where the vaccination ingredients are mixed with water. You should avoid eating, drinking or taking oral medication for an hour before and after having the vaccination.
For adults and children over the age of six, two doses of the vaccine are needed to protect against cholera for two years. After this, a booster is required if you continue to be at risk.
Children who are two to six years of age will need to have three doses of the vaccine. This will protect them for six months. After this, they will need to have a booster if they continue to be at risk.
All the doses must be taken one to six weeks apart. If more than six weeks passes between doses, you'll need to start the full vaccination course again.
Ideally, the vaccination course should be completed at least one week before travelling.
The cholera vaccine isn't recommended for children under two years of age, because it's not clear how well it works in this age group.
Side effects and precautions
After having the cholera vaccine, less than 1 in 100 people will experience short-term symptoms similar to a mild stomach upset, such as abdominal pain, diarrhoea and nausea. Severe reactions are very rare.
Most people can have the vaccination safely, but you should tell the doctor or nurse before being vaccinated if you:
- have a high temperature (fever) or stomach upset
- are pregnant or think you might be pregnant
- are breastfeeding
- have a condition, or are receiving treatment, that affects your immune system
In these circumstances, you may still be able to have the vaccine if you're at a high risk of getting cholera, but your doctor or nurse may need to check with a travel medicine specialist before giving it to you. The vaccination may need to be delayed if you're unwell with a fever or upset stomach.
You shouldn't have the vaccine if you've had an allergic reaction to the cholera vaccine or any of the vaccine components in the past.