Download Lesson Plans - Paw Paw Public Schools

49
40
o5
1
0 -m i n u t e s
es
si
A
Y
-t
on
An Ounce of Prevention
L
ROLE P
ACTIVIT Y OVERVIEW
SUMMARY
Small groups of students participate in a role play. In the first scene, they learn about
how vaccinations work to protect people against viral and bacterial illnesses. In the
second scene, they are introduced to the use and misuse of antibiotics.
KEY CONCEPTS AND PROCESS SKILLS
1.
Making decisions about complex issues often involves trade-offs (i.e. giving up
one thing in favor of another).
2.
Most infectious diseases are caused by microbes.
3.
The category of “microbes” includes microorganisms, such as bacteria and
protists, and also viruses, which are not considered to be alive.
4.
The human body has natural defenses against infectious diseases. These
include barriers such as skin, linings such as mucus, and white blood cells in
the immune system.
5.
Vaccines help the body build immunity against some viral and bacterial
diseases. When a person is later exposed to that disease, he or she is protected
from catching it.
6.
Antibiotics are effective against many bacterial infections, but not against viral
infections.
KEY VOCABULARY
antibiotic
immune system
bacteria
microbe
cell
trade-offs
disease
virus
evidence
vaccination
Teacher’s Guide
C-243
Activity 49 • An Ounce of Prevention
MATERIALS AND ADVANCE PREPARATION
For the class
*
props, such as a lab coat, hat, set of scrubs/surgical clothes, stethoscope, pale
make-up (for the sick person), etc. (optional)
*
video camera (optional)
*Not supplied in kit
Collect props if you will be using them.
n Teacher’s Note: Decide if you wish all students to perform the role play in groups of
four. Another alternative is to assign the role play to one group to practice and present to the class. This may be a group of students ahead with their work or some students who have trouble with written assignments but excel at performing. Because of
the complexity of the two major ideas contained within the role play (vaccination and
antibiotics), you may wish to introduce, perform, and discuss Scene One during one
class period and then move on to Scene Two in a second session.
TEACHING SUMMARY
Getting Started
1.
Students brainstorm ways to prevent infectious diseases.
Doing the Activity
2.
Students read the role play aloud.
Follow-Up
3.
Review key concepts with the class.
Extension
Students can interview different generations of adults to find out if they can recall
knowing anyone who had polio.
INTEGRATIONS
Language Arts/Drama
Acting out the role play will aid student comprehension of subject matter and allow
individual expression. Interested students can practice and then perform a scene for
the class (either in person or on videotape).
C-244
Science and Life Issues
An Ounce of Prevention • Activity 49
BACKGROUND INFORMATION
Flu
The flu is caused by a variety of related viruses. Flu viruses are highly mutable and each
flu season can produce a new strain of the flu. Each year, the flu causes an average of
20,000 deaths in the U.S., mostly among the elderly. Some flu strains, such as the
Spanish Flu of 1918, are more lethal than others. There have been two other flu epidemics since the 1918 outbreak, one in 1957 and one in 1968. The 1968 epidemic
caused 50,000 deaths in the U.S. Other potentially lethal strains of the flu have been
identified, most recently in 1998 when individuals exposed to chickens in Hong Kong
became seriously ill from a flu that originated in the chickens. All of the chickens in
Hong Kong were destroyed as a result, and the spread of the infection was contained.
Today, a global flu surveillance network monitors the emergence of new flu strains.
Due to advances in treatment and prevention, the death toll in the U.S. from future
flu outbreaks is unlikely to be as high as in 1918 or 1968. However, because the flu
virus is so mutable, there remains a real possibility of a global epidemic.
Today, the flu can often be prevented with a vaccine. The flu vaccine is made from
killed virus and cannot cause the flu. Flu vaccinations reduce the likelihood of catching the flu. Each year, new versions of the flu vaccine are developed, based on which
strains of the flu are predicted to be the most prevalent. Flu vaccinations are inexpensive and have few side effects. (During the late 1970s, the nervous disorder “Guillain Barre” was caused by impurities in the flu vaccine. Since then, better purification
methods have been developed.) People who have received the vaccine and who then
catch the flu usually have a less severe illness. Elderly and immuno-compromised people are considered to be at greater risk of having severe flu infections. These individuals and individuals who may come into contact with them are encouraged to get vaccinated against the flu. The flu vaccine is not recommended for children.
Although the flu is a viral disease, antibiotics have helped reduce the death rate when
complications occur and a bacterial infection sets in. A lung infection or pneumonia
is the major cause of death from the flu. The flu strips the lining of the bronchi and
makes the lungs vulnerable to attack by bacteria. Bacterial pneumonia can be treated
with antibiotics.
Vaccines
Since vaccines are made of either weakened whole viruses or parts of the virus, the
development and sale of vaccines require the approval of the U.S. Food and Drug
Teacher’s Guide
C-245
Activity 49 • An Ounce of Prevention
Administration. The weakened viruses are made by exposing the viruses to chemicals or heat and then purifying the weakened viruses and putting them into a
non-toxic solution. Vaccines such as live, weakened polio vaccine tend to be
more effective at stimulating the immune response but have a very slightly higher risk of side effects. (For this reason, the Centers for Disease Control and Prevention recommended a return to the killed polio vaccine as of January 1999.)
Vaccines are available for many infectious diseases caused by both bacteria and
viruses. In the United States, recommended childhood immunizations include
diphtheria, tetanus, pertussis, hepatitis B, polio, haemophilus influenzae type
b, measles, mumps, rubella, and varicella (chicken pox). Hepatitis A vaccine is
recommended for children and adolescents at high risk for hepatitis A infection. Pneumococcal vaccine and annual influenza vaccine are recommended
for children and adolescents at high risk. International travelers often need additional vaccinations, such as for yellow fever and cholera, depending on where
they are going.
Vaccinations are not available for all contagious illnesses—the common cold,
AIDS, Ebola, Hanta, and other emerging diseases do not yet have vaccines developed against them. Diseases caused by protists, such as malaria, and diseases
caused by worms, such as river blindness, cannot be prevented by vaccination.
Although a vaccine for the flu does exist, it is not currently 100% effective
because of the ability of the flu virus to mutate quickly.
Vaccination programs for children in the United States, along with an increase
in the standard of living and improved sanitation, have been responsible for a
tremendous reduction in childhood death and disability. However, vaccination
has not replaced the need for good hygiene and sanitation.
In the U.S., growing public resistance to getting required vaccinations is becoming a public health issue. Possible reasons for this are that people no longer
remember how serious vaccine-preventable diseases once were and they perceive the risk of vaccination as greater than the risk of infection. This perception
may be due to some serious side effects of vaccines in the past. Current vaccines
are closely monitored over millions of doses. The very small risk of side effects
is generally considered to be outweighed by the risk of catching the disease.
C-246
Science and Life Issues
An Ounce of Prevention • Activity 49
TEACHING SUGGESTIONS
GETTING STARTED
1.
Students brainstorm ways to prevent
infectious diseases.
otics, and introduces the use and misuse of antibiotics. The importance of antibiotic use and misuse is
further developed in activities later in the unit.
Have students read Scene One in their groups of
four. Students can choose or be assigned a specific
role within their group. If you provide each student
Ask students to work in groups of four to brainstorm
with a photocopy of the student pages, each student
answers to the question, How can infectious dis-
can pencil in the appropriate names where required
eases be prevented? Circulate and listen to group
as well as highlight their lines. Provide any props
discussions. Students are likely to raise concepts of
that you have available.
hygiene, sanitation, and vector control.
Allow time for students to complete Scene One.
Ask the class, What diseases have you been vacci-
Then invite one or two groups to present their ren-
nated against? Students are likely to remember vac-
dition of the role play to the class.
cines such as polio, rubella, measles, whooping
cough, diphtheria, etc.
Repeat these steps for Scene Two.
FOLLOW-UP
Have students read the Introduction on page C-90
in the Student Book. Help them relate the role of the
immune system, as presented in Activity 46, “Dis-
3.
Review key concepts with the class.
ease Fighters,” to how vaccines might work. The
Spend time reviewing with the class the difference
role play will reinforce this idea.
between an antibiotic and a vaccination. Student
responses should include that a vaccination is a way
DOING THE ACTIVIT Y
2.
Students read the role play aloud.
to prevent some bacterial or viral illnesses and an
antibiotic is a way to treat bacterial infections only.
Antibiotics are not effective against viral illnesses.
The first scene in the role play teaches students more
You may wish to use a table to summarize these
about vaccination. The second scene addresses the
points, as shown below.
common confusion between vaccination and antibi-
Prevention or Treatment?
Effective Against
Can Help Treat
Vaccination
prevention
viruses, bacteria
flu, measles, tetanus,
diphtheria, polio, etc.
Antibiotics
treatment
bacteria
diphtheria, some types of
pneumonia
Teacher’s Guide
C-247
Activity 49 • An Ounce of Prevention
To foreshadow Activities 51, “The Full Course,” and
n Teacher’s Note: The theme of prevention vs.
52, “Miracle Drugs—Or Not?” ask students, Why
treatment was first raised in the activities on
might doctors prefer to test for bacteria first,
heart disease in Unit B “Body Works,” of Science
instead of prescribing antibiotics right away?
and Life Issues. The same question is now asked
Responses may include cost and possible side effects
in the context of infectious diseases. Many of
of unnecessary medications. Some students may
the principles are the same.
have ideas about antibiotic resistance, which is
2.
brought up in these later activities.
n Teacher’s Note: Analysis Question 4 could be used
Chemicals or heat are used to inactivate the
virus before it is used in a vaccine. A vaccine is
as a debate question for the class, or a discussion
typically a dead or weakened form of the dis-
question for groups of four. Alternatively, you can
ease-causing microbe or parts of the disease-
assign individual students to write the answer and
causing microbe.
then you can assess with the “Using Evidence to
Make Trade-offs” element of the E V I D E N C E
AND
Why are serious side effects from vaccines very rare?
3.
You go to the doctor and find out that you may have
T R A D E - O F F S (ET) variable. You may want to have
the flu. Would you expect to be prescribed an antibi-
students review the ideas presented earlier in this
otic? Explain your answer.
unit. Analysis Question 5 is identical to a question
The flu and colds are caused by viruses. Antibi-
first posed in Activity 32, “Who Infected Whom?”
otics are not generally prescribed against viral
Extension
infections because they are not effective. Students should not routinely expect antibiotics to
Students can interview different generations of
treat colds or flu. (In some cases, when people
adults to find out if they can recall knowing anyone
have low resistance, antibiotics are prescribed
who had polio.
to prevent a bacterial infection from setting in.
For example, in cases of viral pneumonia,
SUGGESTED ANSWERS
antibiotics are sometimes prescribed, not to
TO ANALYSIS QUESTIONS
1.
cure the existing viral pneumonia, but as a pre-
A vaccine prevents the individual from
ventive measure to ensure that a bacterial infec-
catching an infectious disease; it does not
tion does not start.)
treat the disease after the person has caught it.
What are some advantages of preventing, rather
than treating, infectious diseases?
Advantages to prevention include reduced suffering (e.g., physical, emotional, time lost from
work and family, etc.) and reduced expense
(e.g., hospitalization, medication, etc.).
4.
Do you think that vaccinations against the
flu should be required? Explain. Support
ET
uet
your answer with evidence and identify the tradeoffs of your decision.
Hint: To write a complete answer, first state your
opinion. Provide two or more pieces of evidence that
support your opinion. Then consider all sides of the
issue and identify the trade-offs of your decision.
C-248
Science and Life Issues
An Ounce of Prevention • Activity 49
•
Complete and correct level 3 responses are
that otherwise wouldn’t. But you shouldn’t
shown below:
force people to do things like get a shot
I think vaccinations should be required.
against a disease that isn’t that serious.
Vaccines help your immune system fight
infectious diseases. Giving people vaccines
would reduce the chance that they would
5.
Reflection: Explain whether you would change your
answer to Question 4 if the disease had more severe
symptoms and a greater chance of causing death.
catch the disease. If fewer people had the
•
disease, then fewer people would get sick.
Some students who said no to Question 4 may
Every time I get the flu, I miss almost a whole
say yes to Question 5 due to the greater severi-
week of school, and it’s so hard to make it up.
ty of the symptoms. In fact, most students have
The trade-off is that vaccines do not always
had vaccinations against polio and other seri-
work 100% and you might have to force
ous diseases.
people to get a vaccination against their will.
This question raises some of the criteria used in
People hate to get shots.
making decisions about public health policy.
Vaccines against the flu shouldn’t be required.
The seriousness of the disease and the possibil-
First of all, it’s not a very serious disease for
ity of serious complications are two factors
most people. Second, you can still get the flu
involved in decisions about vaccinations. As
even if you have the vaccination. And there
more vaccinations are developed, students may
might be side effects to the vaccination.
be required to have additional vaccinations in
Unfortunately, some people might get the flu
order to attend school.
Teacher’s Guide
C-249