Voronoi Diagram, Cholera Outbreak and Beer | Viv•i•fy ...€¦ · Voronoi Diagram, Cholera...

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11/3/19, 10:23 AM Voronoi Diagram, Cholera Outbreak and Beer | Viv•i•fy : ( verb) : to endow with renewed life Page 1 of 6 https://vivifychangecatalyst.wordpress.com/2015/07/25/voronoi-diagram-cholera-outbreak-and-beer/ fy : ( verb) : to endow with renewed life Voronoi Diagram, Cholera Outbreak and Beer JULY 25, 2015 ~ VIVIFYCHANGECATALYST “After careful inquiry, we see no reason to adopt this belief. We do not feel it established that the water was contaminated in the manner alleged; nor is there before us any sufficient evidence to show whether inhabitants of that district, drinking from that well, suffered in proportion more than other inhabitants of the district who drank from other sources.” -William Farr, British Epidemiologist Georgy Voronoy was Ukrainian mathematician, who came up with a spatial analysis technique which is named after him- Voronoi diagram. It’s a diagram created by taking pairs of points that are close together and drawing a line that is equidistant between them and perpendicular to the line connecting them. That is, all points on the lines in the diagram are equidistant to the nearest two (or more) source points. The figure shown below tells how a Voronoi diagram is made. It has number of applications in field of science and technology ex. in cell biology, astrophysics, geometry, ecology etc. It is also used in field of epidemiology, where Voronoi diagrams can be used to correlate sources of infections in epidemics. Infact a similar technique was used by British Physician Dr. John Snow even before George Voronoy was born. In 1854, there was outbreak of Cholera in Soho district of London esp. in areas close to Broad Street. Soho district then was facing problem of large influx of migrants. There were no proper housing and sanitation facilities, resulting in dirt and filth. Lack of sewer lines resulted in all waste (human and animal) getting dumped in Thames River. REPORT THIS ADREPORT THIS AD If Your Dog Does This, It Could Be Them Signaling A Warning What Your Dog Is Trying To Warn About If They Lick Their Paws If Your Dog Does This, It Could Be Them Signaling A Warning What Your Dog Is Trying To Warn About If They Lick Their Paws If Your Dog Does This, It Could Be Them Signaling A Warning What Your Dog Is Trying To Warn About If They Lick Their Paws $49.95 $44.95 $35 $18.47 $27.47 $27.47 $34.97

Transcript of Voronoi Diagram, Cholera Outbreak and Beer | Viv•i•fy ...€¦ · Voronoi Diagram, Cholera...

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11/3/19, 10:23 AMVoronoi Diagram, Cholera Outbreak and Beer | Viv•i•fy : ( verb) : to endow with renewed life

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Viv•i•fy : ( verb) : to endow with renewed life

Voronoi Diagram, Cholera Outbreak and Beer

JULY 25, 2015 ~ VIVIFYCHANGECATALYST“After careful inquiry, we see no reason to adopt this belief. We do not feel it established that thewater was contaminated in the manner alleged; nor is there before us any sufficient evidence to showwhether inhabitants of that district, drinking from that well, suffered in proportion more than otherinhabitants of the district who drank from other sources.”

-William Farr, British Epidemiologist

Georgy Voronoy was Ukrainian mathematician, who came up with a spatial analysis technique whichis named after him- Voronoi diagram.

It’s a diagram created by taking pairs of points that are close together and drawing a line that isequidistant between them and perpendicular to the line connecting them. That is, all points on thelines in the diagram are equidistant to the nearest two (or more) source points.

The figure shown below tells how a Voronoi diagram is made. It has number of applications in fieldof science and technology ex. in cell biology, astrophysics, geometry, ecology etc.

It is also used in field of epidemiology, where Voronoi diagrams canbe used to correlate sources of infections in epidemics.

Infact a similar technique was used by British Physician Dr. JohnSnow even before George Voronoy was born.

In 1854, there was outbreak of Cholera in Soho district of Londonesp. in areas close to Broad Street. Soho district then was facing problem of large influx of migrants.There were no proper housing and sanitation facilities, resulting in dirt and filth. Lack of sewer linesresulted in all waste (human and animal) getting dumped in Thames River.

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(https://vivifychangecatalyst.files.wordpress.com/2015/07/cholera2.jpg)

This filth and stench resulting from it gave rise to Miasma Theory. Miasma was considered to be apoisonous vapour or mist filled with particles from decomposed matter (miasmata) that causedillnesses. The miasmatic position was that diseases were the product of environmental factors such ascontaminated water, foul air, and poor hygienic conditions. Such infection was not passed betweenindividuals but would affect individuals within the locale that gave rise to such vapours. It wasidentifiable by its foul smell. This theory had its supporters including epidemiologist Willaim Farr.

(https://vivifychangecatalyst.files.wordpress.com/2015/07/foul-air.png)

It was easy to correlate filth in Soho district with outbreak of Cholera.

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Dr. Snow has different theory. He did not believe in Miasma theory. He believed that Cholera wasspread by contaminated water rather than foul air. To prove his theory, he studied map of Sohodistrict and cases of Cholera in different areas of district.

(https://vivifychangecatalyst.files.wordpress.com/2015/07/snow-cholera-map-sm1.jpg)

“That is possible; but I believe that the poison of the cholera is either swallowed in water, or gotdirectly from some other person in the family, or in the room; I believe it is quite an exception for itto be conveyed in the air; though if the matter gets dry it may be wafted a short distance.”

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-John Snow, British Physician.

He found that maximum number of cases were in and around a water pump in Broad Street. Dr.Snow concluded that water from this pump was responsible for spreading Cholera in region. He toldauthorities to break handle of pump so that people could not draw water from this pump. Thisresulted in sudden drop in Cholera cases, supporting this theory that it was water from pump thatwas spreading Cholera.

(https://vivifychangecatalyst.files.wordpress.com/2015/07/cholera-4.jpg)

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Dr. Snow’s research is pioneering work in areas of spatial analysis and research methodology. Tillthen causative agent for Cholera was not identified. It was much later i.e. 1884, that Germanphysician and microbiologist Robert Koch during his research in India was able to determine thecausative agent of cholera, Vibrio cholera.

It was found that human and animal waste from Soho district was discharged in Thames River. Thiswater got into wells, and pumps were installed to draw water from these wells. The pump at BroadStreet was drawing water from well whose water was contaminated and whoever drank water frompump suffered from Cholera.

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(https://vivifychangecatalyst.files.wordpress.com/2015/07/cholera-3.jpg)

But task of doing extensive research in correlating contaminated water of pump with cases of Cholerawas done by Reverend Henry Whitehead. Whitehead believed in the miasma theory of disease, healso felt that this disease was punishment from God. Initially Whitehead worked to disprove Snow,but after interviewing lot of people, he eventually started believing John Snow’s idea that choleraspreads through water contaminated by human waste. Snow’s work, particularly his maps of theSoho area cholera victims, convinced Whitehead that the Broad Street pump was the source of thelocal infections.

“You and I may not live to see the day, and my name may be forgotten when it comes, but the timewill arrive when great outbreaks of cholera will be things of the past; and it is the knowledge of theway in which the disease is propagated which will cause them to disappear.”

-Reverend Henry Whitehead

There was one exception to this theory, there was a brewery situated near Broad Street pump- LionBrewery, yet workers from this brewery did not suffer from Cholera.

On investigation it was found that workers in brewery were allowed to drink beer free of cost, so theynever drank water. So though the brewery was situated just one block east of the Broad Street pump,workers drank beer instead of water; the fermentation killed the cholera bacteria, and none of thebrewery workers contracted cholera.

Drinking beer proved to be life saver.

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POSTED IN UNCATEGORIZEDBEER BROAD STREET CHOLERA OUTBREAK DR. JOHN SNOW GEORGE

VORONOY HENRY WHITEHEAD MIASMA THEORY ROBERT KOCH SOHODISTRICT SPATIAL ANALYSIS VORONOI DIAGRAM

One thought on “Voronoi Diagram, Cholera Outbreakand Beer”

1. waldemarSAYS:JUNE 12, 2019 AT 2:53 PMHi,Thanks for the great article, I am preparing a paper on cholera I was wondering the source of theimage of John Snow removing the handle with his bear hands ?Thanks,W

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