Disease Diffusion Flashcards
What causes the spread of disease?
Crowded living conditions
Unclean water
Low income
Inadequate education
What are the 4 main types of disease diffusion?
Expansion
Relocation
Contagious
Hierarchical
Describe expansion diffusion:
Disease has a source and spreads into new areas
Source area stays infected
(E.G. TB outbreak)
Describe relocation diffusion:
Disease leaves origin area
E.G. HIV
Describe contagious diffusion:
Spread occurs through direct contact with others
E.G. Ebola
Describe hierarchical diffusion:
Disease spreads from large urban areas to smaller ones (transport links etc..)
(E.G. SAARS)
Define disease diffusion:
Process by which disease spreads outwards beyond its geographical source
Who made the diffusion model that we looked at?
Hagerstrand
What shape was the Hagerstrand Diffusion Model?
S shaped curve
What are the (3) most important concepts of Hagerstrand’s Diffusion Model?
Neighbourhood Effect
S shape represents number of people infected
Physical barriers interrupt progress
What are the 4 stages of the Hagerstrand Diffusion Model?
Primary
Expansion
Condensation
Saturation
What is the Neighbourhood Effect?
People living in close proximity have a greater probability of contraction
Describe the primary stage of the Hagerstrand Diffusion Model:
Disease begins to grow and spread
Diffusion rate is slow bc few have the disease
Describe the expansion (diffusion) stage of the Hagerstrand Diffusion Model:
Rapid acceleration in disease diffusion (hierarchical diffusion)
Describe the condensation stage of the Hagerstrand Diffusion Model:
Most people have the disease -> spread is limited
