Do Now:
 If your town was being evacuated and
you could only take 3 items with you,
what would it be?
 How much money do you spend in one
day? (Think about lunch, coffee,
movies, clothes, etc.)
Why Do Some Regions Face Health Threats?
What is Epidemiology?
 This is the branch of medical science
concerned with the frequency,
distribution, and control of diseases
that are prevalent among a population
at a special time and are produced by
some special causes not generally
present in the affected locality.
Epidemiologic Transition
 This transition focuses on distinctive
health threats in each stage of the
demographic transition.
 There are 4 stages, with a possible 5th
stage.
 This concept was created by Abdel
Omran in 1971.
Stage 1: Pestilence & Famine
(High CDR)
 In this stage infectious and parasitic diseases
were principal causes of human deaths, along
with accidents and attacks by animals and
humans.
 Malthus called these causes of deaths “natural
checks” on the growth of the population in
stage 1 of the demographic transition.
 Ex. Black (Bubonic) Plague 1347-1350 ½ of the
European human population died– about 25
million.
Stage 2: Stage of Receding
Pandemics (Rapidly Declining CDR)
 Pandemic: disease that occurs over a wide
geographic area and affects a very high
proportion of the population.
 What has reduced the spread of
infectious diseases?
 Improved sanitation, medicine and better
nutrition – this can be seen during the
Industrial Revolution.
Stage 3: Degenerative Diseases
(Moderately Declining CDR)
 This stage is characterized by a
decrease in deaths from infectious
diseases and in increase in chronic
disorders associated with aging.
 Ex. Cardiovascular Diseases (heart
attacks) and various forms of cancer.
Map of Male Cancer Rate
Question: Why is cancer more widespread in
developed areas versus developing ones?
Stage 4: Delayed Degenerative
Diseases (Low but Increasing CDR)
 This transition was extended by S. Jay
Olshansky & Brian Ault.
 Though the degenerative causes of death still
exist, life is extended through medical
advances.
 Improved health changes such as better diet
and decrease in tobacco and alcohol use, also
lead to a longer lifespan.
 However, there as been recent consumption of
non-nutritious foods and less exercise which
has resulted in obesity in many areas.
Possible Stage 5: Reemergence of
Infectious & Parasitic Diseases
 There are 3 reasons for the possible
stage 5: evolution, poverty and
increased connections.
 Evolution:
 Infectious disease microbes have
continuously evolved in response to
environmental pressures by developing
resistance to drugs and insecticides.
Stage 5 Continued
 Poverty:
 In poorer nations they are unable to
afford the drugs needed to fight disease
and they have unsanitary conditions,
therefore infectious diseases are more
prevalent in these areas.
Stage 5 Continued
 Increased Connections:
 As people travel, they carry diseases
with them and are exposed to the
diseases of others.
 Ex. AIDS diffused from Sub-Saharan
Africa through relocation diffusion,
both by Africans and visitors to Africa
returning to their home countries.
Health Care
 Two important indicators of health in a
country are the infant mortality rate
and life expectancy.
 Infant Mortality Rate (IMR): the
annual number of deaths of infants
under one year of age, compared with
total live births. This is usually
expressed as the number of deaths
among infants per 1,000 births.
Health Care Continued
 Generally, the IMR reflects a country’s
health-care system. Lower IMRs are found
in countries with well-trained doctors,
modern hospitals and large supplies of
medicine.
 Life Expectancy: at birth measures the
average number of years a newborn infant
can expect to live at current mortality
levels.
Provision of Health Care
 Children still remain at risk in
developing countries because many lack
the resources to immunize their
children.
 Expenditures on health care exceed 15%
of total government expenditures in
Europe and North America, compared to
less than 5% in sub-Saharan Africa and
South Asia.
Medical Services
 The high expenditure on health care in
developed countries is reflected in medical
facilities.
 Ex. Most countries in Europe have more
than 50 hospital beds per 10,000 people,
compared to fewer than 20 in sub-Saharan
Africa and South and Southwest Asia.
 Europe has more than 30 doctors per 10,000
people and sub-Saharan Africa has fewer
than 5 doctors per 10,000 people.
Hans Rosling “The Good News of
the Decade?”