Epidemiology: Historical Aspects

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Epidemiology Historical Aspects

• Introduction to Epidemiology
• Sharon Cooper, Ph.D.
• PH 2610
• May 22, 2001

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• Major epidemiology contributions to study of
  disease?(small sampling puerperal fever,
  cholera, smallpox, lung cancer, coronary heart
  disease, AIDS)
• A. Human disease associated with living
  environmentHippocrates (460-377 BC)

Whoever wishes to investigate medicine properly
should proceed thus in the first place to
consider the seasons of the year, and what
effects each of them produces. Then, the winds,
the hot and the cold, especially such as are
common to all countries, and then such as are
peculiar to each locality.One should consider
most attentively the waters which the inhabitants
use, whether they be marshy and soft, or hard and
running from elevated and rocky situations, and
then if saltish and unfit for cooking.and the
mode in which the inhabitants live, and what are
their pursuits, whether they are fond of drinking
and eating to excess, and given to indolence, or
are fond of exercise and labor. (On
Airs, Waters, and Places)

• Amazing insightfew discoveries for 2000 years!

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• B. Counting and Measurement (John Graunt and
  William Farr)

• John Graunt
• London businessman who published Natural and
  Political Observations Made upon the Bills of
  Mortality (1662)analyzed parish records of
  christenings, burials, and causes of death
• demonstrated the uniformity and predictability
  of .biological phenomena taken in the mass
• Backdrop against which epidemiologic methods
  would develop

• William Farr
• Physician responsible for medical statistics in
  Office of the Registrar General for England and
  Wales in 1839
• Developed techniques for data collection
• Categorized occupations and diseases
• Involved in first modern census in Great Britain

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Careful Observations (Igmatz Semmelweis,
Hungarian obstetrician, 1818-1865)

• Greatest fear of pregnant women (puerperal fever)
• Viennese Maternity HospitalDr. Semmelweis
  clinical director in 1840s.
• Dr. S. noted mothers in Clinic 1 became ill
  either immediately during birth or within 24-36
  hours after delivery (rapid death) not in clinic
  2
• Differences between Clinic 1 and 2? Medical
  students delivered in Clinic 1 Midwives in
  Clinic 2
• Determined germs being passed from patient to
  patient by the physician while doing pelvic exams
• Discovered that washing hands with chlorinated
  lime before beginning exams impacted mortality
  rates substantially (declined from 12.1 to 1.3
  in 1842)

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Natural Experiment John Snow (1813-1858)Father
of Epidemiology

• Anesthesiologistadministered chloroform to Queen
  Victoria during childbirth
• 20 years before discovery of microscope, Snow
  discovered cause of disease and prevented
  recurrence
• Descriptive epidemiology?hypothesis
  generation?hypothesis testing?public health
  application
• 1831first British case of cholera diagnosed in
  port city of Sunderland
• Epidemic of 1832deaths of 5000-7000 people
• Second epidemic in 1848-9Snow participated in
  Londons Epidemiological Society
• Spread of cholera followed international travel
  routes

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Natural Experiment John Snow (1813-1858)Father
of Epidemiology

• Magnitude of cases suggested communicable mode of
  transmission Diseases which are communicated
  from person to person are caused by some material
  which passes from the sick to the healthy.
• Snow hypothesized that water could carry the
  cholera pathogen from one area to another when
  wells, streams, or pipes are contaminated by
  sewage from household where cholera occurred.
  Snow mapped the occurrence of cholera cases in
  London from August to September 1854. Concluded
  Broad Street pump was the cause of cholera.
• Second major contribution In 1849, Snow noted
  that cholera rates particularly high in areas of
  London supplied by Lambeth Co. or Southwark and
  Vauxhall Co (SV), both drew water from Thames
  River where it was heavily polluted with human
  sewage.
• Between 1849 and 1854, Lambeth Co. relocated
  source upstream to less polluted part of river
  incidence of cholera declined (SV the same)
• Within subdistricts supplied by both
  companies--for every house in which a death from
  cholera occurred

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Figure 1.1 Distribution of cholera cases in the
Golden Square area of London, August-September
1854
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Table 1.1 Mortality from cholera in the
districts of London supplied by the Southwark and
Vauxhall Company and the Lambeth Company, July
9-August 26, 1854

Source Snow, 1936 as cited in CDC, 1992.
Table 1.2 Mortality from cholera in London
related to the water supply of individual houses
in districts served by both the Southwark and
Vauxhall Company and the Lambeth Company, July
9-August 26, 1854
Source Snow, 1936 as cited in CDC, 1992.
Source Page et al., 1995
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The Power of Statistics Florence Nightingale
(1820-1920)

• Collaborator with Farr
• Convinced, based on data, that the British Army
  administration needed reform
• Analysis of mortality statistics for military and
  civilian menmilitary mortality higher than
  mortality among civilian males of similar age
• One of first examples to using health care data
  to affect governmental reforms
• An epidemiologist who did not know it

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Ten Great Public Health AchievementsUnited
States, 1900-1999

• Vaccination
• Motor-vehicle safety
• Safer workplaces
• Control of infectious diseases
• Decline in deaths from coronary heart disease and
  stroke
• Safer and healthier foods
• Healthier mothers and babies
• Family planning
• Fluoridation of drinking water
• Recognition of tobacco use as a health hazard

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