This series of lessons will introduce students to epidemiology
through infectious diseases and the scientific methods epidemiologists
use to investigate those diseases. Although these same methods
are used to investigate other health issues (for example,
chronic disease, environmental problems, behavioral problems,
and injuries), these lessons focus on infectious disease
to provide a clear example of epidemiology that is appropriate
for students at the middle school level. For more information
on the broad applications of epidemiology, see the "What
is Epidemiology?" and "Why Teach Epidemiology?" sections
Each lesson in this module includes one or more activities.
Each activity includes teacher background and student readings,
or age-appropriate Internet links. All lessons align with
national science and health standards, which are noted in
This is a flexible resource package. You may use one or
all of the lessons. However, it is recommended that you
start with Lesson 1, Understanding the Epidemiologic
Triangle through Infectious Diseases. This lesson introduces
the content that students will apply in the remainder of
There are two alternative culminating activities. Lesson
5, Scientific Poster Session, is appropriate for
students of all ages. Lesson 6, Poisoned Picnic,
will work better with older (seventh and eighth grades)
or advanced students.
What is Epidemiology?
Epidemiology is the study of the distribution and determinants
of health problems in specified populations and applying
the learned information to control the health problems.
It is the scientific method of problem solving used by "disease
detectives"—epidemiologists, laboratory scientists, statisticians,
physicians and other health care providers, and public health
professionals—to get to the root of health problems in a
community, whether the problem is a measles outbreak on
a small college campus or a global influenza pandemic, an
increase in homicide in a single community or a national
surge in violence, or a localized or widespread rise in
Like investigators at the scene of a crime, disease detectives
begin by looking for clues. They systematically gather information
about what happened—Who is sick? What are their symptoms?
When did they get sick? Where could they have been exposed
to the illness? Using statistical analysis, investigators
study the answers to these questions to find out how a particular
health problem was introduced into a community.
Disease detectives then use what they have learned to prevent
further illness. For example, when in 1993 more than 200
people in Washington State developed similar gastrointestinal
symptoms, investigators traced the illnesses to undercooked
hamburgers from a fast-food chain. Warnings to cook beef
until it is no longer pink halted the outbreak and prevented
Why Teach Epidemiology?
Epidemiology is an objective, scientific method of problem
solving based on quantitative analysis. Teaching epidemiology
- improves students' reasoning and research skills,
- enhances their ability to analyze and solve complex
- sensitizes them to good health practices.
Ideas and Behaviors Common Among Students
- Students do not understand much about infectious diseases.
In one study of middle and high school students in New
York, over half showed almost no understanding of the
biological concepts of virus, infection, and the immune
system. When they were asked what a virus was, these students
either characterized it as a "sickness," or provided specific
examples (e.g., "stomach virus," "coughing virus") (Keselman
and Patel, 2002).
- A 1953 study that is still cited by many authors showed
that many elementary school students also believe that
germs enter the body through the mouth while eating and
leave the body through the mouth; every illness is caused
by germs; all diseases are caused by the same kind of
germ; the process of infection is automatic; any infection
in the body necessarily makes it ill; and when medicine
is administered, healing takes place immediately (Nagy,
Keselman and Patel. 2002. Sex, Myths, and Adolescents'
Conceptual Understanding of HIV. Laboratory of Decision
Making and Cognition, Department of Medical Informatics,
Nagy, M.H. (1953). The representations of "germs" by children.
Journal of Genetic Psychology, 83, 227-240.