Epidemic Diseases of the 19th Century by dffhrtcv3


									Epidemic Diseases of the
     19th Century
      The Demographic Context
• 19th century experienced explosion of endemic
  & epidemic diseases

• Related to:
  –   Industrialization
  –   Urbanization
  –   Trade activities
  –   Military activities
• Factors were similar to the Middle Ages
• Scale of these changes exponentially greater

• Britain first country to experience
• Associated with:
  – Significant population growth
  – Significant migration to urban centres
• Explosive growth of cities outstripped their
  – Water supply
  – Sewage
  – Housing

• Manchester is an example
          Population Growth in Manchester

300,000                                     1717
200,000                                     1801
150,000                                     1821
 50,000                                     1851
• Northern industrial cities such as Manchester &
  Liverpool grew faster than London
• Result was horrific living conditions for the
  working class
• Subject of many studies
  – Chadwick: Report on the Sanitary Conditions . . .(1842)
  – Engles: Condition of the Working Class . . .(1844)
  – Mearns: Bitter Cry of Outcast London . . .(1883)
• Emergence of statistics helped Britons “see” the
  impact of urbanization
• William Farr
  –   Prominent epidemiologist
  –   2nd Registrar General of the Central Board of Health
  –   Instituted systematic collection of vital statistics
  –   Developed many statistical methods still in use today
• Farr’s 1843 Report concluded that urban life
  expectancy was lower than rural life expectancy
  – Average national life expectancy: 41 years
     • Rural Surrey: 46 years
     • London: 36.7 years
     • Liverpool: 25.7 years
  – Highest mortality in children under age 5
     • ½ of all children in Liverpool dead by 5th birthday
     • In Surrey, ½ dead by age 50
• Several diseases emerged as significant threats to
  health during this time
  – Cholera
  – TB
  – Typhoid Fever
         The Medical Context
• Most physicians & influential lay people believed
  that epidemic diseases were caused by miasma
• Literally “pollution”
• By 19th century, understood as poisonous air
  filled with particles from decomposed matter
• Night air was considered worse
• Idea originated in Hippocratic times
• By 19th century, a few diseases recognized as
  – Smallpox

• Most were not
                            Contagion Theory                 Miasma Theory

Source                      A material substance (animal     Foul air
                            Required index case              Disease generation could be
Mode of Transmission        Person to person                 Local environmental conditions
                            Contaminated water?              Some localities more prone to
                                                             the problem
                                                             Seasonal variations
Signs & Symptoms            Specific to each disease?        Different symptoms could be

Susceptibility              Attacked individual only once?   Attacked individuals repeatedly

Conditions Determining End Not well understood.              Removal of source of miasma
of Outbreak                Should be when everyone was
• Miasma theory supported by many prominent
  19th century health reformers
  – William Farr
  – Florence Nightingale
• Made more sense given the knowledge of the
• Under girded the sanitary emphasis of the 1st era
  of the public health movement
• Miasma theory also supported by business
  community & politicians
• Would make quarantine unnecessary
• This kept international trade & military activity
• An important example of a disease that
  successfully moved out of its original geographic
• “concentrated people’s minds” (Porter)

• Cause: bacteria Vibrio cholerae
• Severe diarrheal disease spread through
  contaminated water
• Death can occur within hours
• Victims were frightening to behold
  – Complete loss of control of bodily functions
  – Shock, circulatory collapse
  – Bodies almost black

• Disease is endemic to India
• Often spread by religious pilgrimages
• Always burned out

• In 19th century, the difference was presence of
  Europeans in India
• Spread to Europe, Asia & Africa along trade &
  military routes
• 1st pandemic (1816-18)
  – overland to Nepal, Afghan
  – by sea to Asia, Africa

• 2nd pandemic (1826-1832)
  –   to Russia 1831
  –   Europe, winter of 1831-32
  –   Canada, New York, 1832
  –   Pacific coast, 1834
• Panic in Europe’s major cities
• No one knew what caused it
  – Churches viewed it as a moral issue
  – Others believed it was miasma
• Physicians emphasized protection of individual
• 3rd pandemic (1852-60)
  – Worst impact in Russia
• 4th pandemic (1863-75)
  – Mostly Europe & Africa
• During 3rd pandemic, debate between advocates
  of miasma & contagion crystallized

• Major figure of this era was John Snow (1813-
• Snow spent many years thinking about cholera
  prior to 1854
• In 1831, as a medical student, cared for coal
  miners sick with cholera near Newcastle
  – Later speculated that it was spread by invisible
    entities on their hands
• Living in London by 1848 when cholera struck
• Investigated origins of this outbreak
• Again proposed contagion as reason for spread
• Speculated that contaminated food or water
  might spread the disease

• Published these ideas in 1849
• Provided evidence to support them
• Snow’s hypothesis not well received
• Always alternative, more plausible explanations

• 1854 cholera outbreak in London
• Snow suspected spread was due to contaminated
• Perfect natural experiment existed in the district
  where he was working
• 2 different water companies supplied water to
  the district
  – One drew water from contaminated section of the
    Thames River (Southwark & Vauxhall Co.)
  – One drew water from above the sewage outlets
    (Lambeth Co.)
• Snow traced local victims & determined who
  had consumed water from which source
• Statistical analysis indicated 71:5 ratio of deaths
  from Southwark & Vauxhall as opposed to
• Results still not accepted
• Alternative theories proposed by supporters of
• In late August, cholera broke out in Soho
• Water companies supplying water had a clean
• Snow speculated that a pump on Broad St.
  might be contaminated
• Initial investigation of pump proved negative
• Snow mapped all cholera victims
• Used this evidence to persuade removal of the
  handle of the Broad St. pump
• Epidemic stopped

• Subsequently, source of contamination found
• Several points must be made about Snow’s
  contributions to germ theory
  – He was often unwilling to go head to head with
    colleagues who supported miasma
  – He beat William Budd by 10 days in publishing his
    theory of the spread of cholera
  – Cholera bacillus was seen under a microscope in
    1854 by Fillipo Pacini, whose findings were not
    translated into English
• William Farr proposed an equally plausible
  theory (for the times) as to why cholera deaths
  were concentrated near the Thames River
• Some historians argue that Farr contributed far
  more to epidemiology than did Snow
• Snow just happened to be correct
• By 1860s, germ theory accepted
• V. cholerae “rediscovered by Koch in 1884

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