1852–60 cholera pandemic
The third cholera pandemic (1852–60) was the third major outbreak of cholera originating in India in the nineteenth century that reached far beyond its borders. In Russia, more than one million people died of cholera. In 1853–54, the epidemic in London claimed over 10,000 lives, and there were 23,000 deaths for all of Great Britain. This pandemic was considered to have the highest fatalities of the 19th-century epidemics.
Like the earlier pandemics, cholera spread from the Ganges delta of India. It had high fatalities among populations in Asia, Europe, Africa and North America. In 1854, which was considered the worst year, 23,000 people died in Great Britain.
That year, the British physician John Snow, who was working in a poor area of London, identified contaminated water as the means of transmission of the disease. After the 1854 Broad Street cholera outbreak he had mapped the cases of cholera in the Soho area in London, and noted a cluster of cases near a water pump in one neighborhood. To test his theory, he convinced officials to remove the pump handle, and the number of cholera cases in the area immediately declined. His breakthrough helped eventually bring the epidemic under control. He was a founding member of the Epidemiological Society of London, formed in response to a cholera outbreak in 1849, and he is considered one of the fathers of epidemiology.
1854 Broad Street cholera outbreak
John Snow was a skeptic of the then-dominant miasma theory. He first published his theory in an 1849 essay On the Mode of Communication of Cholera, in which he correctly suggested that the fecal-oral route was the mode of communication, and that the disease replicated itself in the lower intestines.
Having rejected effluvia and the poisoning of the blood in the first instance, and being led to the conclusion that the disease is something that acts directly on the alimentary canal, the excretions of the sick at once suggest themselves as containing some material which being accidentally swallowed might attach itself to the mucous membrane of the small intestines, and there multiply itself by appropriation of surrounding matter, in virtue of molecular changes going on within it, or capable of going on, as soon as it is placed in congenial circumstances.— John Snow (1849)
Snow's 1849 recommendation that water be "filtered and boiled before it is used" is one of the first practical applications of germ theory in the area of public health and is the antecedent to the modern boil-water advisory.
He identified the source of an 1854 cholera outbreak as the public water pump on Broad Street (now Broadwick Street). Although Snow's chemical and microscope examination of a water sample from the Broad Street pump did not conclusively prove its danger, his studies of the pattern of the disease were convincing enough to persuade the local council to disable the well pump by removing its handle. This action has been commonly credited as ending the outbreak, but Snow observed that the epidemic may have already been in rapid decline.
Snow later used a dot map to illustrate the cluster of cholera cases around the pump. He also used statistics to illustrate the connection between the quality of the water source and cholera cases. He showed that the Southwark and Vauxhall Waterworks Company was taking water from sewage-polluted sections of the Thames and delivering the water to homes, leading to an increased incidence of cholera. Snow's study was a major event in the history of public health and geography. It is regarded as one of the founding events of the science of epidemiology.
Later, researchers discovered that this public well had been dug only three feet from an old cesspit, which had begun to leak fecal bacteria. The diapers of a baby, who had contracted cholera from another source, had been washed into this cesspit. Its opening was originally under a nearby house, which had been rebuilt farther away after a fire. The city had widened the street and the cesspit was lost. It was common at the time to have a cesspit under most homes. Most families tried to have their raw sewage collected and dumped in the Thames to prevent their cesspit from filling faster than the sewage could decompose into the soil.
After the cholera epidemic had subsided, government officials replaced the handle on the Broad Street pump. They had responded only to the urgent threat posed to the population, and afterward they rejected Snow's theory. To accept his proposal would have meant accepting the fecal-oral method transmission of disease, which they dismissed.
- "Cholera's seven pandemics". Canadian Broadcasting Corporation. Archived from the original on 16 December 2008.
- "London Epidemiology Society". UCLA. Retrieved 22 October 2012.
- Dunnigan, M. (2003). "Commentary: John Snow and alum-induced rickets from adulterated London bread: an overlooked contribution to metabolic bone disease". International Journal of Epidemiology. 32 (3): 340–1. doi:10.1093/ije/dyg160. PMID 12777415.
- Snow, J. (1857). "On the Adulteration of Bread As a Cause of Rickets". The Lancet. 70 (1766): 4. doi:10.1016/S0140-6736(02)21130-7.
Reedited in Snow, J. (2003). "On the adulteration of bread as a cause of rickets" (PDF). International Journal of Epidemiology. 32 (3): 336–7. doi:10.1093/ije/dyg153. PMID 12777413.
- John Snow (1849). On the Mode of Communication of Cholera. London: J. Churchill.
There is no doubt that the mortality was much diminished, as I said before, by the flight of the population, which commenced soon after the outbreak; but the attacks had so far diminished before the use of the water was stopped, that it is impossible to decide whether the well still contained the cholera poison in an active state, or whether, from some cause, the water had become free from it
- Chapelle, Frank (2005). "Ch. 5: Hidden Life, Hidden Death". Wellsprings. New Brunswick NJ: Rutgers University Press. p. 82. ISBN 978-0-8135-3614-9.