Cholera is a severe infectious disease most commonly found in tropical climates and developing countries. The symptoms are violent diarrhoea with characteristic "rice water stools", vomiting, thirst, muscle cramps due to loss of salts and occasionally the collapse of the circulatory system.
Death can occur as quickly as a few hours after the start of the symptoms, with the death rate being 50% in untreated cases. With proper medical care this can fall to less than 1%.
Cholera is caused by the bacteria Vibrio cholerae, which was discovered by a German physician and bacteriologist Robert Koch in 1883. It can only be spread from contaminated food and water or the faeces of people with cholera.
It is easy to prevent the spread of the disease through basic sanitation, providing fresh clean water and food. There were severe cholera epidemics in both Europe and the United States in the 19th century, but the disease was rarely seen after the water supply was upgraded.
Despite this cholera is still a chronic problem in many countries where clean water is unavailable. The world health organisation estimates that 78% of people living in developing counties do not have access to clean water and 85% do not have a safe method of removing faecal waste.
There is a vaccine available that lasts from three to six months after immunisation. Scientists are working on a vaccine containing a live bacteria that has been genetically altered and will not cause cholera but will protect against infection.
Cholera produces a toxin that causes the large intestine to secrete large amounts of fluid. This causes the patient to become severely dehydrated, there no longer enough liquid in the body to carry out other cellular functions. An effective form of treatment is injecting fluids and salts either intravenously or orally.
The World Health Organisation has produced packets containing sodium, potassium, chloride, bicarbonate and glucose which are mixed with water and effectively treats the cholera. This has reduced the number of cases of cholera, although it still a serious problem.
