Disease Dilemmas
Key Terms
- Infectious: caused by pathogenic microorganisms such as bacteria, viruses, parasites and
fungi, the diseases can be spread directly (in contact with someone) or indirectly (through
other mediums)
● E.g. common cold
- Non-infectious: diseases that are not transmitted to other people, usually caused by
genetics, lifestyle and environmental factors
● E.g. cardiovascular diseases
- Communicable: an infectious disease which can be transmitted by direct or indirect ways
(effectively the same)
● E.g. flue
- Non-communicable (NCDs): a medical condition or disease that is non-transmissible,
usually of long duration and slow progression (also known as chronic diseases), currently
the leading cause of death worldwide
● E.g. dementia
- Contagious: an infectious disease with is very easily transmissible by direct contact with
someone who has it or with the bodily fluids of a patient (or if they touched an object
recently)
● E.g. Covid19
- Non-contagious: an infectious disease that is not able to be caught by touching people or
things that are infected by it, usually requires a vector (e.g. mosquitoes) or by non casual
transfer of bodily fluids (e.g. blood transfusion)
● E.g. malaria
- Epidemic: an increase, often suddenly, in the number of cases of a disease above what is
normally expected in the population of that geographical area, an outbreak may occur on a
restricted area or could extend across countries
● E.g. ebola, SARS
- Endemic: a disease that exists permanently in a geographical area or human group
denoting a spatial or temporal pattern of disease occurrence
● E.g. chicken pox is endemic to toddlers
- Pandemic: defined as an epidemic occurring worldwide or over a very wide area, crossing
international boundaries and usually affecting a large number of people
● E.g. Covid19
- Pestilence: a contagious or infectious epidemic disease that is virulent and devastating
● E.g. Plague
- In developed countries, non-communicable diseases account for a much higher proportion
of deaths than in LIDCs, as poorer countries lack the education and resources to deal with
highly preventable and treated infectious disease
1
, Disease Dilemmas
Global Distribution of Disease
- Epidemiology is the study of how often diseases occur in different groups of people and
why they do so
Malaria
- Concentrated near the equator, largely in Africa
centred in hot humid areas
- Anopheles mosquitoes can only survive in
specific conditions and need pools of stagnant
water to reproduce
- Less developed countries around the equator
may not have the resources to manage stagnant
water or the preventative knowledge and funding
to reduce transmission
HIV
- Concentrated in Africa and the southern
hemisphere
- Less effective knowledge and use of protective
contraception (e.g. condoms) meaning transmission
occurs to a greater extent
- Countries will civil unrest that interrupts education
programs also see higher prevalence
Tuberculosis
- Concentrated in southern Africa, south Asia and
Russia
- Developing countries are likely to have overcrowded
houses and slum settlements that provide optimal
conditions for transmission
- LIDCs also may not have the resources to control
and treat the spread of tuberculosis or build new
houses that reduce the overcrowding
Diabetes
- More prevalent in more developed countries
e.g. China, Russia and USA
- Access to processed food and the
movement to sedentary lifestyles as tertiary sector
jobs take over promote an inactive lifestyle and
increase Type 2 diabetes cases
- Largely non fatal, the majority of fatal cases
come in countries without sufficient healthcare to
treat the patients with regular insulin jabs
- Increasing cases in the developing world as
fast food TNCs spread into new countries
2
, Disease Dilemmas
Cardiovascular Disease
- Highest mortality rate is Eastern
Europe and North Asia with
increasing rates in Africa
- Cardiovascular diseases are more
based on lifestyle choices, often
through use of addictive substances
like cigarettes and alcohol that
increase risk massively
- Some countries may not have
treatments readily available as they
can place huge cost on the healthcare system
Disease Diffusion
- We follow the Hagerstrand Model of Diffusion when thinking about the diffusion of disease
- 4 main types of diffusion in the model: expansion, relocation, hierarchical, contagious
- Expansion:
● In expansion diffusion the disease has a source and spreads outwards into new
areas directly from the source whilst the carriers in the original location remain
infected e.g. tuberculosis
- Relocation:
● A disease leaves its area of origin and moves into a new area, e.g. 2010 cholera in
Haiti epidemic showed the movement of cholera from Nepal several thousand miles
away into Haiti through aid workers
- Hierarchical:
● A disease that spreads through an ordered sequence of places usually starting with
hub cities in larger countries and moving into smaller isolated areas later
- Contagious
● Describes the spread of disease through direct contact with a carrier, strongly
influenced by distance e.g. ebola epidemic in West Africa
- The Hagerstrand model also considers the neighbourhood effect
- This refers to the probability of contact between a carrier and a non-carrier and can be
calculated by the number of people in a 5x5km square area
- The S shaped curve model refers to the 4 stages of diffusion: primary step, expansionary
step, condensation step and saturation step
- At first the curve begins slowly and then accelerates during peak transmission before
slowing and plateauing at the point where the majority of the susceptible population have
been infected and therefore new cases decrease
3
Key Terms
- Infectious: caused by pathogenic microorganisms such as bacteria, viruses, parasites and
fungi, the diseases can be spread directly (in contact with someone) or indirectly (through
other mediums)
● E.g. common cold
- Non-infectious: diseases that are not transmitted to other people, usually caused by
genetics, lifestyle and environmental factors
● E.g. cardiovascular diseases
- Communicable: an infectious disease which can be transmitted by direct or indirect ways
(effectively the same)
● E.g. flue
- Non-communicable (NCDs): a medical condition or disease that is non-transmissible,
usually of long duration and slow progression (also known as chronic diseases), currently
the leading cause of death worldwide
● E.g. dementia
- Contagious: an infectious disease with is very easily transmissible by direct contact with
someone who has it or with the bodily fluids of a patient (or if they touched an object
recently)
● E.g. Covid19
- Non-contagious: an infectious disease that is not able to be caught by touching people or
things that are infected by it, usually requires a vector (e.g. mosquitoes) or by non casual
transfer of bodily fluids (e.g. blood transfusion)
● E.g. malaria
- Epidemic: an increase, often suddenly, in the number of cases of a disease above what is
normally expected in the population of that geographical area, an outbreak may occur on a
restricted area or could extend across countries
● E.g. ebola, SARS
- Endemic: a disease that exists permanently in a geographical area or human group
denoting a spatial or temporal pattern of disease occurrence
● E.g. chicken pox is endemic to toddlers
- Pandemic: defined as an epidemic occurring worldwide or over a very wide area, crossing
international boundaries and usually affecting a large number of people
● E.g. Covid19
- Pestilence: a contagious or infectious epidemic disease that is virulent and devastating
● E.g. Plague
- In developed countries, non-communicable diseases account for a much higher proportion
of deaths than in LIDCs, as poorer countries lack the education and resources to deal with
highly preventable and treated infectious disease
1
, Disease Dilemmas
Global Distribution of Disease
- Epidemiology is the study of how often diseases occur in different groups of people and
why they do so
Malaria
- Concentrated near the equator, largely in Africa
centred in hot humid areas
- Anopheles mosquitoes can only survive in
specific conditions and need pools of stagnant
water to reproduce
- Less developed countries around the equator
may not have the resources to manage stagnant
water or the preventative knowledge and funding
to reduce transmission
HIV
- Concentrated in Africa and the southern
hemisphere
- Less effective knowledge and use of protective
contraception (e.g. condoms) meaning transmission
occurs to a greater extent
- Countries will civil unrest that interrupts education
programs also see higher prevalence
Tuberculosis
- Concentrated in southern Africa, south Asia and
Russia
- Developing countries are likely to have overcrowded
houses and slum settlements that provide optimal
conditions for transmission
- LIDCs also may not have the resources to control
and treat the spread of tuberculosis or build new
houses that reduce the overcrowding
Diabetes
- More prevalent in more developed countries
e.g. China, Russia and USA
- Access to processed food and the
movement to sedentary lifestyles as tertiary sector
jobs take over promote an inactive lifestyle and
increase Type 2 diabetes cases
- Largely non fatal, the majority of fatal cases
come in countries without sufficient healthcare to
treat the patients with regular insulin jabs
- Increasing cases in the developing world as
fast food TNCs spread into new countries
2
, Disease Dilemmas
Cardiovascular Disease
- Highest mortality rate is Eastern
Europe and North Asia with
increasing rates in Africa
- Cardiovascular diseases are more
based on lifestyle choices, often
through use of addictive substances
like cigarettes and alcohol that
increase risk massively
- Some countries may not have
treatments readily available as they
can place huge cost on the healthcare system
Disease Diffusion
- We follow the Hagerstrand Model of Diffusion when thinking about the diffusion of disease
- 4 main types of diffusion in the model: expansion, relocation, hierarchical, contagious
- Expansion:
● In expansion diffusion the disease has a source and spreads outwards into new
areas directly from the source whilst the carriers in the original location remain
infected e.g. tuberculosis
- Relocation:
● A disease leaves its area of origin and moves into a new area, e.g. 2010 cholera in
Haiti epidemic showed the movement of cholera from Nepal several thousand miles
away into Haiti through aid workers
- Hierarchical:
● A disease that spreads through an ordered sequence of places usually starting with
hub cities in larger countries and moving into smaller isolated areas later
- Contagious
● Describes the spread of disease through direct contact with a carrier, strongly
influenced by distance e.g. ebola epidemic in West Africa
- The Hagerstrand model also considers the neighbourhood effect
- This refers to the probability of contact between a carrier and a non-carrier and can be
calculated by the number of people in a 5x5km square area
- The S shaped curve model refers to the 4 stages of diffusion: primary step, expansionary
step, condensation step and saturation step
- At first the curve begins slowly and then accelerates during peak transmission before
slowing and plateauing at the point where the majority of the susceptible population have
been infected and therefore new cases decrease
3
