Cholera

Last updated: 28 November 2007

What is cholera?

Cholera is a severe diarrhoeal illness caused by infection with cholera bacteria, Vibrio cholerae. In some developing countries, Vibrio cholerae bacteria contaminates drinking water, uncooked seafood and other foods.

What are the symptoms?

Symptoms begin from a few hours to up to five days after infection. Symptoms include sudden onset of severe, watery diarrhoea, sometimes with vomiting. In developing countries, up to 50 per cent of cases die from dehydration and kidney failure. Infection without symptoms or with only mild diarrhoea also occurs, particularly in children.

How is it spread?

Cholera is usually spread through:

• Drinking contaminated water
• Eating raw or undercooked seafood from contaminated waters and
• Eating other contaminated foods.

Who is at risk?

People who are most likely to get cholera are travellers to developing countries where cholera occurs.

How is it prevented?

If you are diagnosed with cholera:

• Ensure you maintain good hygiene. Wash your hands with soap and running water for 10 seconds after using the toilet, and do NOT prepare food for others.
• If you are a foodhandler, do not attend work until cholera is no longer detected in your stools.

People who have shared the same exposures as someone diagnosed with cholera (i.e. shared food or drink from the same source) should see a doctor and be tested.

Imported white bait, shellfish and other seafood eaten whole should be cooked thoroughly before consumption.

When travelling to developing countries where cholera occurs do NOT:

• Drink water unless it is bottled or boiled
• Use ice that may have been made with untreated water
• Eat uncooked vegetables and fruit. Fruit with intact peels (bananas and oranges) that you can peel yourself is safe

• Avoid raw or undercooked seafood
• Avoid food and drinks from street vendors
• Eat only cooked foods that are served hot
• Protect food from against contamination by flies
• Wash hands with soap and running water for 10 seconds before meals and after using the toilet.

How is it diagnosed?

Laboratory tests are required to identify the bacteria from a faecal specimen. Specialist tests are needed to confirm that the bacteria carries the cholera toxin.

How is it treated?

Cholera can be treated with fluids and salts. Patients are treated with oral rehydration solution, a solution of sugar and salt water and drunk in large amounts. Severe cases may require intravenous fluid replacement. With prompt rehydration, fewer than 1% of cholera patients die.

Antibiotics can shorten the course and reduce the severity of the illness, but they are not as important as rehydration.

Persons who develop severe diarrhoea and vomiting in countries where cholera occurs should seek medical attention promptly.

What is the public health response?

Laboratories and hospitals are required to notify cases of cholera to the local Public Health Unit under the Public Health Act, 1991. Public Health Units investigate cases to identify possible sources of infection and to prevent spread.