Download Medical Geography

Epidemiology
The study of
the distribution of diseases
Medical Geography
The study of health from a spatial perspective
Medical geography includes:
The study of overall health and nutrition patterns
Locational analysis (where hospitals should be
built, emergency planning, GPS systems)
Epidemiology
"Health is a state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity."
--The World Health Organization
Epidemiology
epi = upon
dem = people
ology = the study of
The Greek “god” of medicine was Asclepius and
his staff, the caduceus , is now known as a symbol
for medicine. Hippocrates, a member of the Guild
of Asclepius, is known as the “Father of Medicine.”
Types of epidemics
An epidemic is when a disease strikes
many people in a population at the
same time
An endemic is an epidemic limited to a
certain region
A pandemic is a worldwide epidemic
Epidemiology is the study of
the distribution of diseases in
an attempt to:
Determine the cause of the disease
Determine how the disease spreads
Halt the spread of disease
John Snow
1854 London
Cholera Epidemic
How Diseases Spread
Infectious diseases are spread by agents,
disease-causing organisms
Infected people or animals are called hosts
If a population contains many hosts, it becomes a
reservoir for the disease
When a disease is spread through an intermediate
host, it is called a vectored disease
Non-biological vectors are called vehicles
Diseases spread directly from host to host are
non-vectored diseases
Cholera
Bacterial disease (mapped by John Snow)
Water and food are the vehicles
Originally endemic to India until early 1800s
The main reservoir for this disease is marine
shellfish and plankton
Causes diarrhea and dehydration
Re-emerging disease that can be halted through
proper sewage treatment, safe food handling, and
clean water supplies
250,000+ cases in 1999 with 9,000+ deaths
Epidemiology is the study of
the distribution of diseases in
an attempt to:
Determine the cause of the disease
Determine how the disease spreads
Halt the spread of disease
Environmental Impact on Disease
Many diseases live only part of life-cycle
within humans
These diseases must be able to survive
outside the human body
Warm, humid environments are more
conducive to disease survival
As people push into tropics, they
increase their risk of encountering
diseases
Human Habits
Many disease organisms spread through
fecal-oral mode of transmission
Sexually transmitted diseases (STDs)
can be reduced or eliminated
Person-to-Person contact is often
transmitted through coughing or
sneezing
E. coli
Bacterium found in human and cattle
excrement (and deer, goats, and sheep)
Early E. coli outbreaks associated with
contaminated ground meat
Now associated with farm workers not
having adequate bathroom facilities
60,000 yearly infections in the U.S. with
a death rate of 1/1,000
Reduce Diffusion of Disease
Cover your mouth when you cough or sneeze
Wash your hands regularly when ill
Human Habits for Health
Eat right
Get exercise
Avoid smoking
Get enough sleep
Take time to relax
The Bubonic Plague
The Plague is a contagious disease caused by
the agent bacillus, a rod-shaped bacteria,
that resides in the intestines of fleas.
The Plague’s Hosts
The primary hosts of the plague are fleas,
but rodents, cats, dogs, and humans
can also become intermediary hosts.
The Plague
The plague is a vectored disease because it is
spread through intermediate hosts, such as rats.
The plague can become a non-vectored
disease when the plague gets into the lungs.
Symptoms of the Plague
Headaches
Weakness
Chills
Pustules
Swollen lymph nodes
Bleeding under skin
Plague Pandemics
There have been 3 pandemics, or global
epidemics, during historical times.
The First Pandemic
Resulted in people flocking to the Church
Church gained power
The Second Pandemic
Killed 1/3- 1/2 of Europe’s population, and
about that same amount in the Middle East
People became disenchanted with the
church’s inability to halt the plague
Survivors could ask for, and receive, high
wages, thus ending the feudal manorial
economic system
The Third Pandemic
Began in 1855
Truly global
Plague bacillus identified in 1894
Discovered in 1898 that fleas transmitted
disease
Cure found in the 1930s
Reservoirs established in the Americas
World Distribution of Plague