What is cholera?

Cholera is a bacterial infection of the intestine resulting from ingestion of the organism Vibrio cholerae. It is usually transmitted through infected water or food. The infection can be mild or without symptoms, but sometimes it can be severe.

In people who are severely affected, rapid loss of body fluids leads to dehydration and shock. Without treatment, death can occur within hours.

What are the symptoms of cholera?

Only a small percentage of those infected develop severe symptoms and most do not even know that they have been infected.

Symptoms include:

  • Profuse watery diarrhoea.
  • Vomiting.
  • Leg cramps.

Patients with serious illness may lose enormous quantities of body fluid and require resuscitation with rapid intravenous fluids (fluids given into the vein). But for most people the disease is likely to be indistinguishable from travellers' diarrhoea.

How is cholera transmitted?

A person may get cholera by drinking water or eating food contaminated with the cholera bacterium. In an epidemic, the source of the contamination is usually the faeces of an infected person. The disease can spread rapidly in areas with inadequate treatment of sewage and drinking water.

The cholera bacterium may also live in salt water rivers and coastal waters. Shellfish eaten raw are a source of cholera. The disease is not likely to spread directly from one person to another, therefore, casual contact with an infected person is not a risk for becoming ill.

Where is cholera prevalent?

Cholera has been very rare in industrialised nations for the last 100 years. However, the disease is still common today in other parts of the world, including the Indian subcontinent and sub-Saharan Africa.

The global picture of cholera changes periodically. The cholera epidemic in Africa has lasted more than 20 years. Major improvements in sewage and water treatment systems are needed in many of these countries to prevent future epidemic cholera. In January 1991, epidemic cholera appeared in South America and quickly spread to several countries.

How can cholera infection be prevented?

In the EU, because of advanced water and sanitation systems, cholera is not a major threat. However, everyone, especially travellers, should be aware of how the disease is transmitted and what can be done to prevent it.

A vaccine for cholera is available; however, it confers only brief and incomplete immunity, and is not recommended for travellers. Although cholera can be life-threatening, it is easily prevented and treated.

All travellers to areas where cholera has occurred should observe the following recommendations:

  • Avoid foods and beverages from street vendors.
  • Avoid salads.
  • Avoid undercooked or raw fish or shellfish.
  • Drink only water that you have boiled or treated with chlorine or iodine. Other safe beverages include tea and coffee made with boiled water, and carbonated, bottled beverages with no ice.
  • Eat only foods that have been thoroughly cooked and are still hot or fruit that you have peeled yourself.
  • Make sure all vegetables are cooked.
  • The simple rule of thumb is 'boil it, cook it, peel it or forget it'.

How is cholera treated?

Cholera can be simply and successfully treated by immediate replacement of the fluid and salts lost through diarrhoea. The affected person can be treated with an oral rehydration solution, a pre-packaged mixture of sugar and salts to be mixed with water and drunk in large amounts. This solution is used throughout the world to treat diarrhoea.

Antibiotics shorten the course and diminish the severity of the illness, but they are not as important as rehydration. People who develop severe diarrhoea and vomiting in countries where cholera occurs should seek medical attention promptly. Severe cases also require intravenous fluid replacement.

Do I need a cholera immunisation certificate?

No, but in certain circumstances it can help you avoid unnecessary harassment at border crossings. In 1969, because of fears that the disease might be spread by travellers, the World Health Organisation introduced mandatory cholera immunisation for travel to certain parts of the world - but the scheme proved ineffective and was dropped.

The WHO no longer recommends cholera immunisation for travellers and has stated that immunisation certificates should not be required of any traveller. Unfortunately, border guards still sometimes demand certificates on inland borders in sub-Saharan Africa and South America.

Why does cholera have such a reputation?

Cholera was once one of the biggest killers in Irish society. The 1832 epidemic killed 30,000 people and a further outbreak after the famine probably killed as many again. Folk memories of the cartloads of bodies during the 1832 epidemic helped inspire Bram Stoker to write the novel 'Dracula'.

Where can I get further information?

Your GP will be able to advise you on the precautions necessary for travel to various regions.

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