disease dilemmas

• Types of disease diffusion

  Expansion= disease spreads outwards from a source onto new areas and often weakens as it expands

  Relocation= When a disease leaves the area of origin and moves into new areas

  Hierarchal= disease spreads through an ordered sequence of places

  Contagious= spreads depending on direct contact between carriers and is influenced by distance ( influences other types/ r factor)
• Physical barriers to diffusion

  Distance, biome, climate, mountains, seas
• Socio-political barriers to diffusion

  Political borders, curfews, quarantine, Hygiene, vaccinations

  social distancing
• Hagerstrand diffusion model

  stimulates the spread of disease from its origin taking into account three things, population density, change over time and barriers

  
• Effect of climate on disease

  Temperature= many diseases are carried by mosquitos that survive in tropical areas

  Precipitation= many diseases are carried by mosquitos that begin their life cycles in stagnant water
• effect of relief on disease

  Altitude is linked to temperature, in Ethiopia malaria is concentrated in the humid lowlands but not in the cooler highlands.
• Effect of water on disease

  contaminated water such as sewage water can contain bacteria responsible for cholera and other water bourne disease.

  Stagnant water provides a habitat for a mosquitos initial life stages.
• Epidemiological transition model was proposed by Abdul owen who says that societies undergo change in 3 stages:

  The age of pestilence and famine

  The age of receding pandemics

  Post industrial societies the rate of mortality slackens.

  The branch of medicine which deals with the incidence, distributions and possible control of diseases and other factors relating to health.
• describes relation of evolution to type of disease.

  A)

  
• Malaria is an infectious, communicable disease transmitted by the anopheles mosquito between dusk and dawn. The distribution of the disease is in sub-Saharan Africa and where there are large bodies of stagnant water.
• HIV is a infectious, contagious communicable disease. It is distributed in mainly sub-southern Africa and by south east Asia e.g. Eswatini. People who do drugs and share needles or have intercourse without protection can increase the spread of HIV. The disease attacks cells in the immune system.
• Tuberculosis is an infectious communicable disease that is spread worldwide but mainly concentrated in the africa and south east Asia. Once a person is infected, they can spread the disease to others through the air, it can also survive on a surface for several hours. It can be transmitted by close contact with those who already have it
• Diabetes is a non communicable disease that is mainly in ACs and EDCs as they have more access to food that is high in sugar/fat. As more people consume processed food and live a sedentary lifestyle it increases the chance of getting type 2 Diabetes. The amount of sugar in the blood controlled by insulin it can no longer break down glucose into energy.
• CVD is a non communicable disease that is caused by a lack of oxygen in the blood,
• disease diffusion is the spatial spread outwards from its origin
• factors that increase the rate of spread for zoonotic disease