Disease diffusion

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Disease diffusion
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Aspatial models

• disease spread needs susceptible population time

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Torsten Hägerstrand

• 1916-2004(Swedish)
• one of the earlyquantitativegeographers
• worked on time/space diffusion processes

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Diffusion

• expansion
• relocation
• combination

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Observed diffusionof measles in Iceland
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Hamer-Soper models of disease diffusion
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Geographical epidemiology

• contagion diffusion notunderstood until C19th
• germ theory is only 150years old!
• pioneers Semmelweis (Hungarian in Austria
  childbed fever, 1847)
• Joseph Lister (sterile surgery)
• but most famously

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John Snow (1813-58)

• pioneer of ether and chloroform
• cholera endemic in Bengal until 1816 then a
  pandemic outbreak

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Choleras spread
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A Court for King Cholera (1852)
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The power of the microscope
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• The Broad Street pump

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An old problem?

• yes no.

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