Transcript The Sociology of Infectious Disease: Using Middle School

The
Epidemiologic
Triangle
Contagion
Epidemiology
• Epi – means “on, upon, befall” (ex: epidermis)
• Demo – means “people” (ex: demographics,
the study of populations)
• -ology – means “the study of”(ex: biology,
geology)
• So, epidemiology is literally defined as “the
study of that which befalls people”
Epidemiology
• Epidemiology – learning how diseases are
distributed in a certain place and time
• Your homework this week is an epidemiological
study
• How?
– You will look at most common diseases amongst your
age group (you)
– You will look at most diseases other members of your
family might have gotten
– From this information, we should be able to draw
conclusions as a class about why certain diseases
appear in certain populations at particular times
Epidemiology
• The Center for Disease Control (CDC) uses a
model called the Epidemiologic Triangle to
pinpoint outbreaks of infectious diseases
The triangle has three vertices:
• Agent, or microbe that
causes the disease (the
“What” of the triangle
• Host, or organism harboring
the disease (the “who” of
the triangle)
• Environment, or those
external factors that cause
or allow disease
transmission (the “where”)
AGENT
HOST
The center of the
triangle is TIME –
this is what
epidemiologists are
working against
TIME
ENVIRONMENT
Outbreaks, Epidemic vs. Endemic
• An outbreak or epidemic exists when there are
more cases of a particular disease than
expected in a given area, or among a specific
group of people, over a particular time.
– Example: Seasonal flu
• Endemic means a population has a high level
of disease all the time.
– Example: Malaria is endemic in Africa
Example Case Study: Varicella zoster
(chickenpox)
People under 15 most at risk
Anyone who hasn’t had it is
susceptible
Can remain in the body and
cause shingles (painful blisters)
in adults
Varicella
zoster, a
virus
AGENT
HOST
Transmitted from
an infected
person through
coughs or
sneezes, or from
contact with the
fluid from
chickenpox
blisters
Most commonly
transmitted in
the early winter
or spring, when
temperatures are
moderate
ENVIRONMENT
Mystery Disease
• Watch the following clip: Mystery Disease
• While watching, look for the following
epidemiological clues:
– How might it be spreading? (Agent)
– Who/what is getting disease? (Host)
– Where is it happening? (Environment)
Mystery Solved!
• Let’s see if you were right… Mystery Solved
Public Service Announcement Skits
• Working in your table groups, use the information
from the case study provided to create a Public
Service Announcement skit about your disease.
• It can be a radio broadcast, TV commercial, talk
show interview, etc… be creative!
HOST
• In your skit, include…
– The epidemiological triangle for
how your disease is transmitted,
including time
-What people should do
AGENT
avoid getting disease
TIME
ENVIRONMENT
Common Infectious Diseases (HW or
Classroom Activity)
I’ve Had
Family Members Have
Had
Heard About
Compare the diseases you’ve had, and diseases your family
has had with your table. What diseases do you have in
common? What diseases did your family have that you
haven’t had? Why do you think this is? What are some
diseases you’ve heard about, but don’t know anyone who
has had that disease?