HAGERSTRAND MODEL OF DIFFUSION

Question 1

WHAT DOES HAGERSTRAND MODEL SHOW

Answer 1

The process by which a particular disease spreads across space (location) and time.

Question 2

Why is it useful ?

Answer 2

Provides a framework for understanding disease diffusion
Allows comparison between diseases
Need to understand to develop effective mitigation strategies
Shows effectiveness of barriers eg physical (relief) & human (PPE, border controls)

Question 3

Does it apply to all types of Disease?

Answer 3

No, it only covers COMMUNICABLE DISEASES only

Non-communicable diseases result from genetics, lifestyle factors & environemntal factors

Question 4

How many types of spatial diffusion are there?

Answer 4

Four TYPES of Diffusion - demonstrates the neighbourhood effect
Neighbour hood effect - if live in a densely populated area more likely to get disease

1.EXPANSION DIFFUSION
Disease spread outwards from its source
Eg Covid 19, Spanish Flu

2. RELOCAION DIFFUSION
   Disease moves from one location to another
   Eg Cholera moved into Haiti by aid worker
3. CONTAGIOUS DIFFUSION
   Needs direct contact so highest incidence near source
   Eg Ebola, Black Death
4. HIERARCHIAL DIFFUSION
   Spreads through as sequence of places
   Eg HIV cities–> towns–> villages

Question 5

How many STAGES of diffusion are there (time aspect)

Answer 5

Four STAGES of diffusion (Think about Covid)

1.PRIMARY STAGE
Initial stage - begins to spread from source

2. DIFFUSION STAGE
   Starts to spread rapidly

3.CONDENSING STAGE
Slows down as it begins to reach saturation point

4.SATURATING STAGE
Reaches maximum prevalence and new cases numbers begin to decline

Question 6

WHAT DOE THE S-SHAPE CURVE SHOW

Answer 6

This is a visual representation of the stages of diffusion.

Question 7

Any other variations?

Answer 7

You can get peaks of diffusion
eg summer & winter peaks

Question 8

Diagrams