Download Fighting Infectious Disease

LESSON 35.3
Fighting Infectious
Disease
Getting Started
Objectives
35.3.1 Distinguish between active immunity and
passive immunity.
35.3.2 Describe how public health measures and
medications fight disease.
35.3.3 Describe why patterns of infectious disease
have changed.
Student Resources
Study Workbooks A and B, 35.3 Worksheets
Spanish Study Workbook, 35.3 Worksheets
Lab Manual B, 35.3 Hands-On Activity Worksheet
Lesson Overview • Lesson Notes
• Activity: Data Analysis • Assessment: SelfTest, ­Lesson Assessment
F or corresponding lesson in the
Foundation Edition, see pages 846–848.
Key Questions
How do vaccines and
externally produced antibodies
fight disease?
How do public health
measures and medications
fight disease?
Why have patterns of infectious diseases changed?
Vocabulary
vaccination
active immunity
passive immunity
Taking Notes
Venn Diagram Make a Venn
diagram that compares and
contrasts active and passive
immunity.
Figure 35–14 Jenner
Vaccinating James Phipps
Activate Prior Knowledge Find on the Internet or obtain from the health
department a schedule of recommended vaccinations for children and teens. Show students the
schedule, and ask them how they think vaccinations
help develop immunity. Also, discuss how a community increases its protection against epidemics
of serious infectious diseases as more people in the
community are vaccinated against those diseases.
After the discussion, post the schedule on a classroom bulletin board.
THINK ABOUT IT More than 200 years ago, English physician Edward
Jenner noted that milkmaids who contracted a mild disease called cowpox didn’t develop smallpox. At the time, smallpox was a widespread
disease that killed many people. Jenner wondered, could people be protected from smallpox by deliberately infecting them with cowpox?
Acquired Immunity
How do vaccines and externally produced antibodies
fight disease?
Jenner performed a bold experiment. He put fluid from a cowpox
patient’s sore into a small cut he made on the arm of a young boy
named James Phipps. As expected, James developed mild cowpox.
Two months later, Jenner injected James with fluid from a smallpox
infection. Fortunately for James (and Jenner!), the boy didn’t develop
smallpox. His cowpox infection had protected him from smallpox
infection. Ever since that time, the injection of a weakened form of
a pathogen, or of a similar but less dangerous pathogen, to produce
immunity has been known as a vaccination. The term comes from the
Latin word vacca, meaning “cow,” as a reminder of Jenner’s work.
Active Immunity Today, we understand how vaccination works.
Vaccination stimulates the immune system with an antigen.
The immune system produces memory B cells and memory T cells
that quicken and strengthen the body’s response to repeated infection.
This kind of immunity, called active immunity, may develop as a
result of natural exposure to an antigen (fighting an infection) or from
deliberate exposure to the antigen (through a vaccine).
Passive Immunity Disease can be prevented in another way.
Antibodies produced against a pathogen by other individuals
or animals can be used to produce temporary immunity. If externally produced antibodies are introduced into a person’s blood, the
result is passive immunity. Passive immunity lasts only a short time
because the immune system eventually destroys the foreign antibodies.
Passive immunity can also occur naturally or by deliberate exposure.
Natural passive immunity occurs when antibodies are passed from a pregnant woman to the fetus (across the placenta), or to an infant through
breast milk. For some diseases, antibodies from humans or animals can be
injected into an individual. For example, people who have been bitten by
rabid animals are injected with antibodies for the rabies virus.
national science education standards
1020
Lesson 35.3
• Lesson Overview
• Lesson Notes
UNIFYING CONCEPTS AND PROCESSES
II, IV
1020_Bio10_se_Ch35_S3_1020 1020
CONTENT
C.1.a, C.3.a, C.4.e, F.1, F.5, F.6, G.3
Teach for Understanding
3/26/11 9:37 AM
ENDURING UNDERSTANDING The human body is a complex system. The coordinated
functions of its many structures support life processes and maintain homeostasis.
INQUIRY
A.1.b, A.2.a, A.2.b
GUIDING QUESTION How do humans prevent and fight the spread of disease?
EVIDENCE OF UNDERSTANDING After completing the lesson, this assessment should
show student understanding of how humans prevent the spread of infectious
disease. Ask each student to create an information sheet that could inform the
public about why acquired immunity is important to the prevention of infectious
disease. The sheet can have a combination of words and illustrations. Have
volunteers present their information sheets to the class.
1020 Chapter 35 • Lesson 3
1008_mlbio10_Ch35_1020 1020
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1020_Bio10_se_C
How Do Diseases Spread?
2 Exchange results with your classmates to determine
how the “virus” spread through the classroom. Wash
your hands with soap and warm water.
1
Your teacher has placed a fluorescent
material in the classroom to simulate a virus.
Keep track of the people and objects you
touch. Then, use a UV lamp to check for the
“virus” on your hands, objects, and people you
have touched since entering the classroom.
CAUTION: Do not look directly at the UV light.
Analyze and Conclude
1. Infer What can you infer about how the “virus”
spread through the classroom?
2. Apply Concepts How does thorough hand
washing help prevent the spread of diseases?
Public Health and Medications
How do public health measures and medications fight disease?
In 1900, more than 30 percent of deaths in the United States were
caused by infectious disease. In 2005, less than 5 percent of deaths were
caused by infectious disease. Two factors that contributed to this change
are public health measures and the development of medications.
Public Health Measures When humans live in large groups, behavior,
cleanliness of food and water supplies, and sanitation all influence the
spread of disease. The field of public health offers services and advice
Public health measures help
that help provide healthy conditions.
prevent disease by monitoring and regulating food and water supplies,
promoting vaccination, and promoting behaviors that avoid infection.
Promoting childhood vaccinations and providing clean drinking water
are two important public health activities that have greatly reduced the
spread of many diseases that once killed many people.
Medications Prevention of infectious disease is not always possible.
Medications, such as antibiotics and antiviral drugs, are other weapons
Antibiotics can kill bacteria, and some
that can fight pathogens.
antiviral medications can slow down viral activity.
The term antibiotic refers to a compound that kills bacteria without
harming its host. In 1928, Alexander Fleming was the first scientist to
discover an antibiotic. Fleming noticed that a mold, Penicillium notatum, seemed to produce something that inhibited bacterial growth.
Research determined that this “something” was a compound Fleming
named penicillin. Researchers learned to mass-produce penicillin just in
time for it to save thousands of World War II soldiers. Since then, dozens
of antibiotics have saved countless numbers of lives.
Antibiotics have no effect on viruses. However, antiviral drugs
have been developed to fight certain viral infections. These drugs
generally inhibit the ability of viruses to invade cells or to multiply
once inside cells.
In Your Notebook How does your school promote public health?
Lesson 35.3
P #1710
#1710
Broad
B
Br
roa
ad St
S
Street
re
eet P
Pump
u p
um
FIGURE 35–15 Broad Street Pump
In 1854, through investigation that
included interviewing residents and
mapping, Dr. John Snow learned
that the source of a London cholera
outbreak was a water pump like this
replica. This is a major event in the
history of public health.
If Steere’s patients were
helped by antibiotics,
what clue would this
have given him about
the disease’s pathogen?
• Data Analysis
LPR Less Proficient Readers Give students five minutes to write a response to this common saying: An
ounce of prevention is worth a pound of cure. Ask
them to explain what the saying means and whether
they agree or not with its meaning.
Suggest students review the text to find
out which pathogens are affected by
antibiotics. Students can go online to
Biology.com to gather their evidence.
Address Misconceptions
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PURPOSE Students infer how an
infectious disease can spread.
ANALYZE AND CONCLUDE
MATERIALS ultraviolet lamp, fluorescent
1. Sample answer: The “virus” was
PLANNING Place a fluorescent
material on a doorknob or other place
students are sure to touch no more
Ask How do inspectors and other government
employees in the community help to prevent the
spread of disease? (Sample answer: Inspectors of
restaurants help prevent diseases spread in food.
The water department makes sure diseases are not
spread in drinking water.)
Have students investigate why a
“germ-free” society can be both good and
bad for human immunity using Data Analysis: Society and Immunity.
than 10 minutes before students arrive.
Station a UV lamp where students can
check to see if they have “contracted
the virus.”
SAFETY Warn students not to look
directly at the UV light. Make sure they
wash their hands after the lab.
Discuss the story of John Snow and the Broad Street
pump introduced in Figure 35–15. Then, talk about
public health measures in the students’ own community that prevent similar outbreaks of serious
diseases. Review with students what they learned
in Lesson 35.1 about the ways infectious diseases
spread.
DIFFERENTIATED INSTRUCTION
0001_Bio10_se_Ch35_S3.indd 2
substance such as Glo Germ™ oil or
dilute fluorescein solution
Lead a Discussion
spread through the classroom by students as they contaminated objects
with their hands.
2. Sample answer: Thorough hand
washing washes viruses off hands.
Therefore, frequent hand washing
would help prevent spread of diseases.
Vaccine Effectiveness Some students may have the
common misconception that vaccines are not effective because the majority of people who get diseases
have been vaccinated. Point out that vaccines are
not 100 percent effective, and a small percentage
of those vaccinated against a disease will become
infected. Routine childhood vaccines, for example,
are 85 to 95 percent effective. That gives a vaccinated person a much greater chance of avoiding a
disease than one who is not vaccinated.
Answers
IN YOUR NOTEBOOK Answers will vary. Students
might mention the school’s nurse, daily cleaning of
the school, a school dietician, and any special efforts
made by school staff to promote healthy behaviors.
Immune System and Disease
1021
LESSON 35.3
Teach
LESSON 35.3
Figure35–16 Causes of Emerging
Teach
continued
Lead a Discussion
Talk about the threat of emerging diseases causing
epidemics in the United States and elsewhere. Point
out that for most of these emerging diseases, either
there is no vaccine, or the vaccines are not available
for wide distribution to a large population.
Disease Illegally imported animals can
lead to the spread of emerging disease.
A. In 2003, dormice and other rodents
from Africa spread monkeypox to
prairie dogs in the United States, which
then infected humans. B. The spread of
SARS also has been associated with the
wild animal trade.
DIFFERENTIATED INSTRUCTION
Advanced Students Ask pairs of students with
a firm understanding of the principles of evolution
to prepare a presentation to the class about how the
misuse of medications results in pathogens that are
resistant to antibiotics and other medications.
l3 A. Dormouse
Assess and Remediate
EVALUATE UNDERSTANDING
Read aloud the lesson’s Key Concepts and the sentences defining new vocabulary terms. In each case,
leave out the most significant term in the sentence.
Call on students to fill in the blanks. Then, have
them complete the 35.3 Assessment.
REMEDIATION SUGGESTION
B. Students wearing masks
to protect them from
diseases such as SARS
New and Re-Emerging Diseases
Why have patterns of infectious diseases changed?
By 1980, many people thought that medicine had conquered infectious disease. Vaccination and other public health measures had wiped
out polio in the United States and had eliminated smallpox globally.
Antibiotics seemed to have bacterial diseases under control. Some
exotic diseases remained in the tropics, but researchers were confident
that epidemics would soon be history. Unfortunately, they were wrong.
In recent decades, a host of new diseases have appeared, including AIDS, SARS, hantavirus, monkeypox, West Nile virus, Ebola, and
avian influenza (“bird flu”). Other diseases that people thought were
under control are re-emerging as a threat and spreading to new areas.
What’s going on?
Changing Interactions With Animals
Two major reasons for
the emergence of new diseases are the ongoing merging of human
and animal habitats and the increase in the exotic animal trade. As
people clear new areas of land and as environments change, people
come in contact with different animals and different pathogens. Exotic
animal trade, for pets and food, has also given pathogens new opportunities to jump from animals to humans. Both monkeypox and SARS
are thought to have started this way. Pathogens are also evolving in
ways that enable them to infect different hosts.
Misuse of Medications
Misuse of medications has led to the
re-emergence of diseases that many people thought were under control.
For example, many strains of the pathogens that cause tuberculosis and
malaria are evolving resistance to a wide variety of antibiotics and other
medications. In addition, diseases such as measles are making a comeback
because some people fail to follow vaccination recommendations.
Review Key Concepts
Struggling Students If students have trouble
answering Question 2b, review the consequences
of misusing medications.
l1 Students can check their understanding of lesson concepts with the SelfTest assessment. They can then take an online
version of the Lesson Assessment.
1.a. Review Explain how vaccinations and externally produced antibodies help the immune system fight disease.
b. Compare and Contrast Describe the difference between
active and passive immunity.
2.a. Review What are the goals of public health measures?
b. Relate Cause and Effect Why is it important to discern if
a sickness is caused by a bacterium or a virus?
3.a. Review Describe two major contributing factors involved
in the spread of new and re-emerging diseases.
b. Infer How do you think the ease of global travel has
affected the spread of emerging diseases? Explain.
Lesson 35.3
Assessment Answers
1a. Vaccination stimulates the immune system
with an antigen. The immune system produces memory B cells and memory T cells
that quicken and strengthen the body’s
response to repeated infection. Externally
produced antibodies, which are antibodies produced against a pathogen by other
individuals or animals, can be used to produce temporary immunity.
1b. Active immunity may develop as a result
of natural exposure to an antigen or
from deliberate exposure to the antigen.
Passive immunity occurs when externally
produced antibodies are introduced into a
person’s blood.
1022 Chapter 35 • Lesson 3
• Self-Test
Science as a Way of Knowing
4.Getting vaccinated is much safer
than getting the disease that the
vaccine prevents. However, like
any drug, vaccines are capable
of causing side effects. As a class,
arrange a debate that addresses
both the benefits and risks of
vaccinations. Debaters on both
sides should use reliable sources
to support their arguments.
• Lesson Assessment
1022 Chapter 35 • Lesson 3
1020_Bio10_se_Ch35_S3_1022 1022
2a. to prevent disease by monitoring food and
water supplies, to promote vaccination, and
to recommend ways to avoid infection
2b. Antibiotics can kill bacteria, but they have
no effect on viruses.
3a. One factor is changing interactions with
animals. As people clear new land and environments change, people come in contact
with new pathogens. Exotic animal trade
has given pathogens new opportunities to
jump from animals to humans. Another factor is the misuse of medicines. Some pathogens are developing resistance to a variety
of antibiotics and other medications.
3b. Sample answer: Global travel has increased
the spread of emerging diseases because
infected people who show no symptoms
can travel around the world very quickly,
spreading the disease more widely than
possible in earlier times.
4. Debate arguments will vary
depending on research results.
Students should find information
in library sources or on the Internet that
describes the fear of death and sickness
caused by vaccines as well as assurances
that vaccines are safe.
12/3/11 9:09 PM
Lead a Discussion
Have students relate the diseases included in the
time line with what they learned in the subsection
New and Re-Emerging Diseases, in Lesson 35.3.
Emerging Diseases Due to factors such as changing interactions with animals and
misuse of medications, the problem of infectious disease is far from solved.
1965
1971
1977
1967
Surgeon General
William H. Stewart
announces, “It is time
to close the book on
infectious diseases.”
1975
Lyme disease is first
documented in the
United States.
1983
1983
HIV is identified as
the cause of AIDS.
1995
2001
2007
2002
2003
DIFFERENTIATED INSTRUCTION
The United States reports its
first case of mad cow disease
in Washington State.
L3 Advanced Students Ask students to report on
one of the emerging diseases on the time line. Tell
them that to find up-to-date information on a disease, they should search reliable sources on the Internet, such as the World Health Organization (WHO)
and the Centers for Disease Control and Prevention
(CDC). Ask students to give a brief presentation to
the class about the disease they researched.
CDC reports cases of monkeypox in people who handled infected prairie dogs.
1996
The British government
admits that humans
can contract BSE from
eating infected beef.
Ask What is an example on the time line of a disease
that emerged as a result of the misuse of medications? (tuberculosis cases in the United States)
Ask How might an American tourist in Asia contribute to the global spread of avian influenza?
(The tourist could come in contact with the virus
and bring it back to America when he or she
returns home.)
First SARS outbreak
occurs in China’s
Guangdong province.
1986
Researchers discover
bovine spongiform
encephalopathy (BSE),
commonly called mad
cow disease, in
cattle in Britain.
1976
First outbreak of Ebola
occurs in the Democratic
Republic of the Congo.
1989
Avian Influenza A strain
H5N1 spreads through
domestic poultry in Asia.
2005
1981
1
First reports surface of
illness later identified as
AIDS in Los Angeles.
FFPO
FP
PO #
#1
#1713
17
71
13
CDC reports that
7.8 percent of tuberculosis cases in the U.S. are
resistant to the first-line
drug used to treat it.
2007
In a short essay, discuss why
Surgeon General Stewart would have been
confident in his 1967 announcement. Then
discuss two factors that have contributed to the
comeback of infectious disease.
Fourteen countries have
reported a total of 351
confirmed human cases of
avian influenza (H5N1) and
219 deaths.
Biology and History 1023
Answers
WRITING Student essays will vary. Students might
0001_Bio10_se_Ch35_BH.indd 1023
6/4/09 2:20:41 PM
Biology In-Depth
THE CASE OF MONKEYPOX
Changing interactions with animals is one factor in the spread of emerging diseases.
An example is monkeypox, a rare viral disease mainly confined to Africa that causes
symptoms in humans similar to smallpox. The disease is called monkeypox because
it was first discovered in monkeys, though the virus can also infect other animals,
including mice and rabbits. In the United States, this disease was first reported in
2003. Investigations revealed that monkeypox had spread to people from their pet
prairie dogs. How did the prairie dogs get an African virus? The source was a shipment of wild African rodents to Texas. The rodents were kept by a seller in close proximity to prairie dogs, which were eventually sold to people as pets.
suggest the Surgeon General may have been
confident of his statement in 1967 because of the
success of vaccinations and antibiotics in preventing
and treating many diseases, such as polio and
tuberculosis. In the discussion of the comeback
of infectious disease, students should describe
changing interactions with animals and the misuse
of medications.
NATIONAL SCIENCE EDUCATION STANDARDS
CONTENT
F.1, F.5, G.3
INQUIRY A.2.a, A.2.f
Biology and History
1023
BIOLOGY & HISTORY
Teach