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1a.3 How do diseases spread to new areas? (Physical Barriers (:warning…
1a.3
How do diseases spread to new areas?
Disease Diffusion
Diseases spread outwards from their origin and
across space
in a process.
Expansion Diffusion
Disease has a source and spreads outwards into new areas.
Carriers in the source remain infected, and the rate of disease often intensifies.
Outbreak of TB
Network Diffusion
Occurs when a disease spreads via transportation and/or social networks.
HIV
Contagious Diffusion
Spread of disease through direct contact with a carrier.
It is strongly influenced by distance because nearby individuals/regions have a much higher probability of contact with disease than remote individuals or regions.
HIV
Hierarchical Diffusion
Disease spread through an
ordered sequence
of places, usually from the largest centres with the highest connectivity to smaller, more isolated centres.
Diffusion is
channeled along road, rail, and air transport networks
which facilitate contact between carriers and a susceptible population.
H1N1 flu virus became a pandemic via international flight routes and airports.
Relocation Diffusion
When a disease leaves the area or origin and moves into new areas.
Migration of disease carriers.
Movement of a person with HIV.
Mixed Diffusion
The spread of a disease is a mixture of types if disease diffusion.
Physical Barriers
Objects in the environment that prohibit interaction (and therefore spread) from taking place.
:warning:
Most important barrier is distance.
:warning:
As distance increases, chance of contraction decreases.
The ocean
Climate
Deserts
Mountains
Socio-economic Barriers
Socio-economic barriers prohibit diffusion when a person's beliefs, culture, wealth or place in society prohibit interaction with certain people or places.
Social isolation
Access to healthcare
Chastity
Not eating certain foods
Barriers used to limit spread of disease
Vaccination
Awareness/education
Face Masks
Cancelling public events
Access to condoms