how did it become accepted that cholera was spread by ingesting infected water?
TRANSCRIPT
How did it become accepted that Cholera was spread by ingesting
infected water?
Explain how miasmic theorists came to accept that Cholera was
spread by consuming infected water…
Miasmatists…
Edwin ChadwickPoor Law Commission Secretary
John SimonLondon Medical Officer William Farr
Chief statistician in marriages and deathsNever
changed his mind!
Changed his mind by 1870
Changed his mind by 1866
Original arguments by Miasmatists
‘diseases are caused by dirty air produced by rotting animals and vegetables .’
‘all smell is disease’Times Newspaper 1853
Chadwick
‘the poison of cholera is an emanation from the earth.’
Florence Nightingale
Criticised building of drains under houses as it could spread miasma causing smallpox and scarlet fever
Dr Duncan (firsts medical officer ever)
‘air below three feet is unsuitable for respiration.’
THE WATER LOOKED CLEAN – NASTY SMELLS WERE EVERYWHERE!
John Snow helped to convert some Miasmatists…
1849 – On the mode of Communication of Cholera – water infected by sewage may cause cholera to spread
1854 Cholera epidemic – Snow produces ‘cholera map’ showing links between deaths and the Broad Street Pump
Snow, ‘-the water propagates the disease and stops it from dying out through not reaching fresh victims.’
Pump handle removed from Broad Street!
Snow produced further evidence of infected water causing Cholera
1853/54 – Snow compared mortality rates of people who drank from different water companies but lived in the same area
Vauxhall Water Companyhad few deaths
Southwark Water Company had many more deaths
Water was spreading disease not infected air!
Snow said water should be boiled and/or filtered
Some Miasmatists still refused to change their minds…
John Simon was still more concerned with removing smells than improving water supply e.g. passed drainage reforms to ‘remove smells.’
‘This disease mist is like an angel of death that has hovered over London for centuries.’
Elevation in feet Cholera deaths per 10,000
0 137
15 50
25 40
35 25
45 20
55 13
65 36 (included level of Broad St Pump)
75 19
Committee for Scientific Enquiry into the Recent Cholera Epidemic (1854)
Farr, Simon, Arnott
‘If the Broad Street Pump did actually become a source of disease – it was not because it contained choleriac elements but because it added to the atmospheric infection of the district.
The spread of cholera is less to do with water than the air.’
‘We see no reason to accept Snow’s findings.’
John Snow suddenly died in 1858 – very few people had realised his genius
The East London Cholera epidemic and the conversion of William
Farr…
• Bazalgette had almost completed his system of intercepting sewers beneath London.
• Most London water companies had built filter beds for their reservoirs…except East London Water Company
• 27th June – Mr and Mrs Hedges died of cholera
• The Cholera spread quickly through the families nearby… all got their water from East London Water Company
1866…
Times Newspaper 1st August 1866
THE RETURN OF CHOLERA
924 PEOPLE DEAD!
ALL GET WATER FROM EAST LONDON COMPANY!
By the end of August 1866 it was estimated that 3,797 deaths out of 4,363 had happened in areas supplied by East London Water Company!
Farr changed his
mind!
‘An indifferent person would have breathedthe air without any
apprehension. But onlya very robust scientist would have dared to
drink a glass of water from East London
Water Company!’
‘Dr Farr has now also agreed; the conclusions made by John Snow in regard to the influence of the water supply in causing disease are irresistible.’
August 1866
The Conversion of John SimonAfter William Farr had at last accepted that Miasmic Theory was incorrect, John Simon was soon to follow suit. In 1870 he wrote…
‘It is now certain that the water supply of a town may be the essential cause of the most terrible epidemic outbreaks of cholera, typhoid fever and dysentery’
‘Dr Snow in 1849 was not able to prove his theory. However, new evidence has established as almost certain that he had been correct.’
In the following years, John Simon and William Farr pushed for further measures to improve the cleanliness of the London Water…
• Bazalgette completed his intercepting sewer system• All Water Companies had to have filter beds in their reservoirs• Pumping stations were built to improve the efficiency of removing sewage
Farr declared that 1867 was the healthiest year for Londonsince 1860, judged by the death rate.
London Death Rate in 1872
21.5 per 10,000 people
A lower rate than Paris, Vienna, Berlin, Brussels, Rome or any other major European, American or Indian city, despite having a population of 3.3million
London Death Rate in 1872
21.5 per 10,000 people
A lower rate than Paris, Vienna, Berlin, Brussels, Rome or any other major European, American or Indian city, despite
having a population of 3.3million
By 1896 Cholera was so scarce in England that it was labelled an ‘exotic disease’
The 1875 Public Health Act forced other cities in Britain to adopt similar measures to improve the
water supply
A CHOLERA
EPIDEMIC HAS NOT
RETURNED TO
BRITAIN SINCE
1866