1.a. Diseases can be classified and their patterns mapped. The spread of diseases is complex and influenced by a number of factors. Flashcards

1
Q

What is an infectious disease?

A

Spread by pathogens (bacteria, fungi, viruses and parasites).

Most but not all can be transmitted from one to another.

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2
Q

What is a non-infectious disease?

A

A disease that cannot be spread.

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3
Q

What is a communicable disease?

A

Spreads from host to host, but does not require quarantine.

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4
Q

What is a non-communicable disease?

A

A disease that cannot be spread.

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5
Q

What is a contagious disease?

A

Spreads through direct or indirect contact between people.

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6
Q

What is a non-contagious disease?

A

A disease spread by disease vectors.

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7
Q

What is a zoonotic disease?

A

An infectious disease spread from animals to humans.

60% of infectious diseases originate in animals.

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8
Q

State 3 of the top 10 causes of death worldwide within ACs.

A
  • Lung cancer. (NC)
  • Kidney disease. (NC)
  • Breast cancer. (NC)
  • Respiratory infections. (I)
  • Diabetes. (NC)
  • Colon cancer. (NC)
  • Pulmonary disease. (NC)
  • Alzheimer’s/ dementia. (NC)
  • Strokes. (NC)
  • Coronary heart disease. (NC)
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9
Q

State 3 of the top 10 causes of death worldwide within LIDCs.

A
  • Malaria. (I)
  • Tuberculosis. (I)
  • AIDS/ HIV. (I)
  • Birth trauma. (NC)
  • Traffic accidents. (O)
  • Pre-term birth complications. (NC)
  • Strokes. (NC)
  • Coronary heart disease. (NC)
  • Respiratory infections. (I)
  • Diarrhoeal disease. (I)
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10
Q

What is an endemic? Give an example.

A

Exist permanently in a geographical area or population group.

E.g. Sleeping sickness within Sub-Saharan Africa, spread from a parasite, tsetse fly, affects more than 9 million a year.

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11
Q

What is an epidemic? Give an example.

A

An outbreak of a disease that attacks many people at the same time, and spreads through population in a restricted geographical area.

E.g. Ebola from 2013 to 2014 - confined to Western Africa (Guinea, Liberia and Sierra Leone); 10,500 deaths confirmed, but there are most likely a lot more.

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12
Q

What is a pandemic? Give an example.

A

An epidemic that has spread worldwide.

E.g. COVID-19.

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13
Q

What type of disease is malaria? Where is it located?

(Global distribution of malaria)

A

Malaria is an infectious but not-contagious tropical disease.

It is connected in Africa, Latin America, South Asia and Southeast Asia.

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14
Q

In 2018, how many people were infected with malaria?

(Global distribution of malaria)

A

220 million people.

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15
Q

In total how many people are at risk of malaria? In how many countries?

(Global distribution of malaria)

A

In total around 3.2 billion people are at risk in 97 countries.

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16
Q

Where was malaria originally thought to have been caused by?

(Global distribution of malaria)

A

It was originally thought to have been caused by the poor air quality found in marshy areas, hence ‘mal’ (bad) air.

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17
Q

Why transmits malaria? Where do these thrives?

(Global distribution of malaria)

A

A parasite, the Anopheles mosquitoes.

These thrive in warm, humid environments.

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18
Q

Where is malaria absent?

(Global distribution of malaria)

A

Large urban areas in the tropics.

In the US states bordering the Gulf of Mexico, and in Northern Australia, effective public health measures have eliminated the disease.

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19
Q

Outline the global distribution, prevalence, and location of malaria.

(Global distribution of malaria)

A
  • Distribution is widely common in LIDCs.
  • Most prevalent in sub-Saharan Africa.
  • Located across the equator.
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20
Q

What type of disease is HIV/AIDS?

(Global distribution of HIV/AIDS)

A

HIV/AIDS is an infectious and contagious disease.

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21
Q

How is HIV/AIDS spread?

(Global distribution of HIV/AIDS)

A

By human body fluids such as blood and semen.

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22
Q

In 2020, how many people were infected by HIV/AIDS worldwide?

(Global distribution of HIV/AIDS)

A

38 million people.

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23
Q

Where is HIV/AIDS mainly concentrated?

(Global distribution of HIV/AIDS)

A

The main concentration of infection is in sub-Saharan Africa, South Africa and Nigeria have the largest numbers of HIV/AIDS cases, while in Swaziland and Lesotho more than a quarter of the population carry the disease.

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24
Q

Outline the global distribution, prevalence, and location of HIV/AIDS.

(Global distribution of HIV/AIDS)

A
  • Distribution is sparse and highly uneven.
  • Most prevalent in Southern Africa.
  • Commonly located in Sub-Saharan Africa.
25
Q

In 2018, how many cases of TB were there globally? How many deaths?

(Global distribution of TB)

A

Over 10 million cases of TB worldwide and 1.5 million deaths.

25
Q

What type of disease is TB?

(Global distribution of TB)

A

TB is an infectious and highly contagious disease associated with poverty and overcrowded living conditions.

26
Q

What region has the highest number of TB deaths?

(Global distribution of TB)

A

Africa, (a large proportion also are HIV/AIDS sufferers).

26
Q

In 2018, what were mortality rates from TB in Nigeria? Mozambique?

(Global distribution of TB)

A

64/100,000 in Nigeria.

72/100,000 in Mozambique.

26
Q

What percentage of TB deaths occurred in LIDCs and EDCs?

(Global distribution of TB)

A

95% of deaths.

27
Q

Outline the global distribution, prevalence, and location of TB.

(Global distribution of TB)

A
  • Distribution is large, some can be found in every continent.
  • Most common in places, such as South Africa.
  • Prevalent largely in central and Southern Africa; and Islands in Asia like Indonesia.
27
Q

Outside Africa, where are TB rates high? What countries?

(Global distribution of TB)

A

Asia, especially in Afghanistan, Myanmar and Cambodia.

27
Q

What type of disease is diabetes? What causes it?

(Global distribution of diabetes)

A

A non-communicable disease.

It is caused by a deficiency of insulin, a hormone secreted by the pancreas.

28
Q

Globally, how many people are affected by diabetes? How many are killed annually?

(Global distribution of diabetes)

A

Nearly 250 million people and is responsible for nearly 4 million deaths annually.

29
Q

Where is diabetes most strongly concentrated?

(Global distribution of diabetes)

A

North America, East and South Asia.

30
Q

What is type-1 diabetes?

(Global distribution of diabetes)

A

Diabetes develops in childhood and is genetic.

31
Q

What is type-2 diabetes?

(Global distribution of diabetes)

A

Occurs in adulthood and is often linked to obesity, poor diet and physical inactivity.

32
Q

Outline the global distribution, prevalence, and location of diabetes.

(Global distribution of diabetes)

A
  • Most prevalent in East Asia and Central North America.
  • Distribution is large; but doesn’t dangerously at least Africa.
  • Most common in areas like India, USA, China and Brazil.
33
Q

CVD covers a range of illnesses, including what?

(Global distribution of CVD)

A

Coronary heart disease, stroke, hypertension and angina.

34
Q

CVD incidence rises steeply with age. How does this affect mortality and morbidity rates?

(Global distribution of CVD)

A

Mortality and morbidity rates increases with ageing populations in ACs.

However, when standardised by age, the highest CVD mortality rates are found in Russia, sub-Saharan Africa and the Arabian Peninsula.

35
Q

CVD is responsible for how many deaths each year? How many occur in LIDCs and EDCs?

(Global distribution of CVD)

A

17 million deaths a year, with 80% occurring in LIDCs and EDCs.

36
Q

Premature death from CVD is linked to what?

(Global distribution of CVD)

A

Lifestyle, particularly to tobacco consumption, unhealthy diet and physical inactivity.

37
Q

Outline the global distribution and prevalence of diabetes.

(Global distribution of CVD)

A
  • Prevalent the most within (south-west) Asia and (north-east) Africa.
  • Distribution is wide, but doesn’t critically affect North and South America.
38
Q

What are the types of disease diffusion?

A

Expansion diffusion.

Relocation diffusion.

Contagious diffusion.

Hierarchical diffusion.

39
Q

Outline expansion diffusion.

A

Occurs from a source, disease spreads outwards into new areas, meanwhile carriers in source area remain infected.

E.g. TB.

40
Q

Outline relocation diffusion.

A

From a source disease moves into new areas spatially separate from the source.

E.g. people carrying a disease from one continent to another.

41
Q

Outline contagious diffusion.

A

From a source, disease spreads through direct contact with a carrier.

Strongly influenced by distance, e.g. Ebola.

42
Q

Outline hierarchical diffusion.

A

From a source disease spreads through an ordered sequence of places usually from largest well connected locations eventually to more isolated and smaller centres.

Can also be seen along transport networks.

43
Q

What is disease diffusion?

A

The spatial spread outwards from an origin.

44
Q

What are barriers to diffusion?

(Barriers to diffusion)

A

Ways in which disease diffusion can be limited, by adding a curfew to limit contact between people.

45
Q

State 3 types of human (socioeconomic) barriers to diffusion.

(Human barriers)
(Barriers to diffusion)

A

Wearing masks in public places, and cancelling public events.

Mass vaccination programmes protect populations against diseases like flu.

Health education constitutes additional barriers to the spread of disease.

Political borders check the international movement of infectious diseases.

46
Q

Give a named example of when human (socioeconomic) barriers to diffusion were implemented.

(Human barriers)
(Barriers to diffusion)

A

This happened in Sierra Leone in 2015 to contain the Ebola virus with western aid workers - limiting the risks of it being spread to the UK and surrounding countries.

47
Q

What is the most important physical barrier to diffusion? What are other examples?

(Physical barriers)
(Barriers to diffusion)

A

Distance, although others include mountain ranges, oceans, deserts etc.

48
Q

The probability of a contagious disease spreading to an area is…

(Physical barriers)
(Barriers to diffusion)

A

Inversely proportional to distance from its source.

49
Q

What physical barrier can act as a major factor in the epidemiology and distribution of diseases such as malaria and sleeping sickness.

(Physical barriers)
(Barriers to diffusion)

A

Climate.

50
Q

Who is Hägerstrand? Outline his model.

(Torsten Hägerstrand’s Disease Diffusion Model)

A

Swedish geographer known for researching the distribution of farming subsidies in rural Sweden.

His theory only applies to contagious diffusion.

His theory had 3 concepts.

51
Q

What are the 3 concepts?

(Torsten Hägerstrand’s Disease Diffusion Model)

A

Concept 1: The Neighbourhood Effect.
Concept 2: The Logistic Curve.
Concept 3: Physical Barriers.

52
Q

Outline ‘The Neighbourhood Effect’, within Hägerstrand’s model.

A

The probability of contact with a carrier is determined by 5km x 5km population density.

People living in close proximity have a higher chance of contracting the disease.

53
Q

Outline ‘The Logistic Curve’, within Hägerstrand’s model.

A

Overtime, there is a slow and gradual rise.

It then accelerates rapidly.

It tails off an slows at the end; this is when the most susceptible people have been infected.

54
Q

Outline ‘Physical Barriers’, within Hägerstrand’s model.

A

Diffusion can be blocked or prevented by physical barriers.

These include mountain ranges, oceans, deserts etc.