Disease and dilemmas
Classification of diseases:
- Diseases can be classified in numerous ways; infectious or non-infectious, contagious
and non-contagious communicable or non-communicable, as epidemics, pandemics
and endemics or as degenerative
Infectious diseases- spread by pathogens (bacteria, viruses, parasites etc), not all can be
transmitted from one person to another. An example of an infectious disease that is non-
contagious= Malaria, as its spread by mosquitos but can’t be passed from human to human.
- Zoonotic diseases- infectious diseases transmitted from animal to human, eg; rabies
or the plague
Non-infectious diseases- come about from lifestyle choices eg; smoking causing lung cancer,
can’t be spread (also called non-communicable diseases
Contagious diseases- a category of infectious diseases that are spread by humans through
direct/ indirect contact, eg; Typhoid, ebola (also called communicable diseases)
Non-contagious- diseases that cannot be passed from human to human
Communicable disease- those that are spread by an infectious agent eg; bacteria, viruses,
fungi, parasites etc (can be spread directly or indirectly from one person to another)
- Can be sub-divided into animal-borne, water-borne and food-borne
Non-communicable= those than are not spread by an infectious agent (this means they are
not directly transferrable from one person to another)
Endemic= exist permanently in a geographical area or population group, eg; sleeping
sickness transferred by the Tsete fly in rural Sub-Saharan Africa or Chagas which is also
transmitted by tiny parasites known as ‘’kissing bugs’’, effecting 7.6 million people in Central
and South America (can also be transferred between humans eg; through blood
transplants). Long term.
Epidemic= an outbreak of disease that attack many people at the same time, spreading
through a population in a restricted geographical area, eg; 2014 Ebola outbreak in Sierra
Leone, Guinea and Liberia effecting 25,000 people and causing 10,500 deaths. Temporary.
Pandemic= an epidemic that has spread world-wide, eg; the black death (mid 14th century)
killing between 75- 200 million and possibly half of Europe’s population in just four years
and the Spanish flu (1918-1919) effecting one third of the world’s population, one in 5
people died (more than 50 million)
Degenerative diseases= are the result of a continuous process based on degenerative cell
changes, affecting tissues or organs, which will increasingly deteriorate over time. 60% of
deaths globally are caused by degenerative
,Non- Communicable diseases (Degenerative and lifestyle diseases) = those than are not
spread by an infectious agent (this means they are not directly transferrable from one person
to another)
- Currently 60% of deaths globally are due to degenerative diseases
- The number of deaths by degenerative diseases is increasing due to;
- An ageing global population eg; nearly 20% of the UK pop is over 65 and it is
estimated there will be an additional 8.6 million people entering the 65+ age bracket
within the next 50 years
- As well as increasing unhealthy lifestyles eg; a Health Survey for England showed
nearly nine in 10 had at least one unhealthy trait, additionally as LICs develop and
move away from subsistence their citizens are more able to access unhealthy
products such as processed food
- Examples include; CVD, cancers, chronic respiratory disease
- Due to lifestyle influencing these diseases (not only age) they also effect younger
people eg; in 2013 16 million people worldwide under the age of 70 died from
degenerative diseases, 82% of these were in low and middle income
Diabetes
- Non communicable
- Type 1 is caused by the pancreas’s failure to produce insulin and is genetic, Type 2 is
caused by the body’s resistance to insulin and is caused by poor diet and lack of
exercise
- The number of people with diabetes has risen from 108 million in 1980 to 422
million in 2014
- Causes 4 million deaths a year
- The global prevalence of diabetes* among adults over 18 years of age has risen from
4.7% in 1980 to 8.5% in 2014
- It is responsible for around 4 million deaths annually
- Burdens high income countries hugely, eg; diabetes costs the NHS 10% of their total
budget (£1.5 million an hour or £25,000 every minute)
Distribution
- Widespread throughout the world however is strongly concentrated in North
America, East and South Asia
- Was previously a disease of HIC’s however is now spreading to middle income
countries, thought to be due to the influx of Western high fat diets eg; the
introduction of MacDonald’s to India in 1996
, CVD (cardiovascular disease)
- Covers a range of illnesses including coronary heart disease, stroke, hypertension
(high blood pressure) and angina
- CVD is responsible for 17 million deaths a year
- CVD is a disease of longevity, linked to tobacco consumption, unhealthy diet and
physical inactivity
Distribution
- Major cause of death in HIC’s with ageing populations
- However, when standardized by age the highest CVD mortality rates are found in
Russia, Sub-Saharan Africa and the Arab Peninsular
- 80% of all deaths occur in low and middle income countries