12 marks: GM

1. How can migration influence the distribution of infectious diseases?

• Migration increases diffusion

• Contributes to pandemics

• E.g. covid-19 from China

Diffusion of diease?

Hagerstrand model of disease diffusion

Expansion diffusion?

• Disease has a source & spreads to new areas

• Carriers in source area remain infected.

• E.g. outbreak of TB

• India hit badly - 210 per 100,000 infected (2021 stats).

Relocation diffusion?

• When disease leaves area of origin & moves into new areas.

• E.g. Cholera in Haiti (2010)

• Killed 8,700 - originated in Nepal + brought to Haiti by international aid workers flown in to tackle earthquake disaster.

Contagious diffusion?

• Spread of disease through direct contact with carrier.

• Strongly influenced by distance.

• E.g. Ebola in West Africa (2014-15).

Hierarchical diffusion?

• Disease spreads though ordered sequence of places - usually from largest centres with highest connectivity to smaller, more isolated centres.

• Also channelled along road, rail & air transport networks - facilitates contact between carriers & susceptible population.

Example?

• E.g. covid (2019/20) became a pandemic via rail journey & international air flights.

• Summer 2020: killed 700,000 globally.

2. How can migration reduce the influence of physical barriers?

• E.g. sea

• Diseases can diffuse worldwide very quickly in more globalised society.

• Diffusion of disease.

Example?

3. How can time space compression increase speed of diffusion?

• Invention of aircraft - people can travel from UK to Wuhan in less than a day, whereas previously it would’ve taken several days.

• Thus, removes natural barriers e.g. oceans & makes places more vulnerable to diseases.

Example?

• covid-19

• Also Cuban example

4. How has urban to rural migration encouraged the spread of disease?

• E.g. Ethiopia

• Leading to more breeding sites for mosquitos in garbage dumps

• Seasonal migration in rainy season - agricultural practices in lowlands.

5. How do bilateral migration corridors aid disease control but also promote it?

• Ease of migration in globalised society reduces barriers to disease diffusion.

• Makes disease control increasingly challenging.

• But, rigorously enforced surveillance for diseases e.g. malaria in Mauritius can be successful in reducing disease diffusion.

• Use example of Mauritius

6. How can knowledge/skills/money of migration reduce the incidence of diseases?

• Migration of high-skilled doctors e.g. Brain Drain (substantial emigration) can help reduce incidence of disease in some countries but increase it in others.

• LIDCs often lose in these migration flows.