History
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Origin
Cholera originated in India or elsewhere in Asia, with the Ganges River likely serving as a contamination reservoir.

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Discovery
The scientists with major contributions to fighting cholera were John Snow, who found the link between cholera and drinking water in 1854, and Robert Koch, who identified Vibrio cholerae as the bacillus causing the disease. The bacterium was originally isolated thirty years earlier by Italian anatomist Filippo Pacini, but his results were widely known arond the world.

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Spread
Cholera was originally endemic to the Indian subcontinent, but spread by trade routes (land and sea) to Russia, then to Western Europe, and from Europe to North America. Major cholera epidemics struck the United States in 1832 (An interesting side-note, when the epidemic reached Canada in 1832, the victims blamed the British and accused them of creating the disease), 1849, and 1866. (The 1849 outbreak took the life of former U.S. President James K. Polk.) Cholera is now no longer considered an issue in Europe and North America, due to filtering and chlorination of the water supply.

First pandemic 1816-1826. Previously restricted , the pandemic began in Bengal, then spread across India by 1820. It extended as far as China and the Caspian Sea before receding.
Second pandemic (1829-1851) reached Europe, London in 1832, Russia (Cholera Riots), Ontario, Canada and New York in the same year, and the Pacific coast of North America by 1834.
Third pandemic (1852-1860) mainly affected Russia, with over a million deaths.
Fourth pandemic (1863-1875) spread mostly in Europe and Africa.
Sixth pandemic (1899-1923) had little effect in Europe because of advances in public health, but Russia was badly affected again.
Seventh pandemic (1961-1970s) began in Indonesia, called El Tor after the strain, and reached Bangladesh in 1963, India in 1964, and the USSR in 1966. From North Africa it spread into Italy by 1973. In the late 1970s there were small outbreaks in Japan and in the South Pacific.
More recently there was an outbreak in South America from January 1991 to September 1994, apparently initiated by discharged ballast water. Beginning in Peru there were 1.04 million identified cases and almost 10,000 deaths. The causative agent was a non-O1, nonagglutinable vibrio (NAG) named O139 Bengal. It was first identified in Tamilnadu state, India and for a while displaced El Tor in southern Asia before decreasing in prevalence from 1995 to around 10% of all cases. It is considered to be an intermediate between El Tor and the classic strain and occurs in a new serogroup. There is evidence as to the emergence of wide-spectrum resistance to drugs such as trimethoprim, sulfamethoxazole and streptomycin.

In the past, people travelling in ships would hang a yellow flag if one of the crews suffered from cholera. Boats with a yellow flag hung would not be allowed to disembark at any harbor. (See Love in the Time of Cholera)

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Treatment
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Prevention
Although cholera can be life-threatening, it is easily prevented and treated. In the United States and Western Europe, because of advanced water and sanitation systems, cholera is not a major threat. The last major outbreak of cholera in the United States was in 1911. However, everyone, especially travelers, should be aware of how the disease is transmitted and what can be done to prevent it.

Simple sanitation is usually sufficient to stop an epidemic. There are several points along the transmission path at which the spread may be halted:

Sickbed: Proper disposal and treatment of waste produced by cholera victims.
Sewage: Treatment of general sewage before it enters the waterways.
Sources: Warnings about cholera contamination posted around contaminated water sources.
Sterilization: Boiling, filtering, and chlorination of water before use.
Filtration and boiling is by far the most effective means of halting transmission. In general, education and sanitation are the limiting factors in prevention of cholera epidemics.