Download Lesson Plans for Infectious Diseases

The Health Science Module of the
Science & Technology Curriculum
Learning and Teaching Resources
Theme:
Diseases and Community Health
Topic:
Infectious Diseases &
Causes and Prevention of Infectious Diseases
The purpose of this set of teaching resources is to provide teachers with
some teaching ideas and updated information on individual themes. The
content of the topics is built on those in the S1-3 Science Curriculum. It
is not expected that every detail in this set of materials is to be covered
in class teaching, as some of the materials only serve as
references/enrichment for teachers. To enhance the effectiveness of
learning and teaching, teachers may need to modify the resources to suit
the needs, abilities and interests of their students. Teachers also have to
note that the materials included are by no means exhaustive, and should
feel free to employ other resources if appropriate.
Table of Contents
Page
Introduction
1
Learning Objectives
1
Scheme of Work
2-6
Lesson Plans
7-13
Teacher/Student Notes




Period 1
Period 2
Period 3
Period 4

What are infectious diseases

Common diseases
transmission routes
their
14-15

Why antibiotics should not be used
in viral infection
16

Photos of pathogens

Microorganisms
industry

Pasteurization
19

Ultrahigh temperature treatment
19

Lab session
20

Food poisoning and preservation
21

Control infectious diseases
21

Food poisoning
22

The principles of food preservation
22

Entry and defense of infectious
agents
23

Transmission of infectious agents
23

Non-specific
mechanism
of
defense against infectious agents
23

Physical barriers
and
and
14
17-18
the
food
19
23-24



Period 5
Period 6
Period 7

Chemical barriers

Microbial antagonism

The immune system and immunity
26

Steps of immune responses
27

How is immunity developed
28

Vaccines and Vaccination
29

What are vaccines
29

Why do we need vaccines
30

How vaccines work
30

Why multiple vaccine doses
31

Examples of how a vaccine works

Control of infectious diseases
33

International Organization
33

Local Organization
34

Roles of health and community
workers
34

Implementation of the vaccination
program
35

What are advantages and risks of
vaccination programs
36
Suggested Activities
Lab Safety Precautions
Culturing Bacteria
Alternative Method of Culturing Bacteria
Bacterial Count between Washed and Unwashed Hands
Review Questions/quizzes/food for thought
Supplementary Resources
24
24-25
31-32
37-40
41
42-43
44
45-46
47

References for Teachers
48

References for Students
48
Causes and Prevention of Infectious Disease
Introduction
Although our treatment of disease has made much progress in the past
decade, our battles against infectious diseases are a never-ending one.
New viruses or bacterial outbreaks occur each year. Many of these
pathogens are emerging from our technological advanced society. Recent
outbreak of West Nile flu in the U.S. is an example of bringing a microbe from
one part of the globe to another with the convenience of air traffic.
Learning Objectives:
After these series of classes, the students will be able to
1. State the difference between bacteria and virus
2. Describe the pasteurization process and identify some food items
required microbes for production
3. Recognize the importance of maintaining personal and environmental
hygiene
1
Scheme of work for Causes and Prevention of Infectious Diseases
Scheme of work for Infectious Diseases (Diseases and Community Health theme ~ Health Science Module)
Topic
Time
I. Infectious
Diseases
Period 1
Learning Objectives
Suggested Activities
1 State the difference between bacteria 1. Video Session
. and viruses.
Watch the videotape “Louis
Resources
Teaching Materials
1. Laboratory manual &
safety precaution
Pasteur’s legacy of hope” from the
distributor Barr Media Group,
Irwindale, CA, USA
2 Describe some common infectious
. diseases and the causative agent.
2. Laboratory Session
will be prepared and
provided by
Biochemistry
Department, CUHK
2.
Carry out a feasible lab
experiment from the suggested
topics
3. Discussion Questions
 How does Dengue fever
spread?
 What is “mad cow” disease?

The organization of
epidemiological services in
Hong Kong. How does Hong
2
(40 mins)
Electron microscopic
images of bacteria,
virus, and fungi will
be supplied by
Biology Department
of CUHK
3.
Freeze-fried
bacterial culture and
other supply can be
ordered from
commercial source
Scheme of work for Causes and Prevention of Infectious Diseases
Kong deal with disease
outbreak?
4. Homework
(beginning at the end of second
period and bring completed to
third period)
Examine the food, environmental,
and personal hygiene at home,
and try to point out the possible
improvements.
3
Scheme of work for Causes and Prevention of Infectious Diseases
Scheme of work for Infectious Diseases (Diseases and Community Health theme ~ Health Science Module)
Topic
I. Infectious
Diseases
Time
Learning Objectives
Suggested Activities
(40 mins)
Resources
Period 2 . 1. Explain the process of pasteurization
of UHT
2. Identify the use of microorganisms in
food manufacturing
Scheme of work for Infectious Diseases (Diseases and Community Health theme ~ Health Science Module)
Topic
Time
Learning Objectives
Suggested Activities
I. Infectious
Diseases
Period 3
. 1. Understand the importance of personal
and environmental hygiene
2. Know the way to avoid food poisoning
3. Know the principles of food
preservation
4
(40 mins)
Resources
Scheme of work for Causes and Prevention of Infectious Diseases
Scheme of work for Infectious Diseases (Diseases and Community Health theme ~ Health Science Module)
Topic
Time
II. Infectious Period 4
Diseases
Learning Objectives
Suggested Activities
(40 mins)
Resources
1. Explain the mode of entry of
infectious agents
2. State the non-specific mechanisms of
defense against infectious agents.
Scheme of work for Infectious Diseases (Diseases and Community Health theme ~ Health Science Module)
Topic
Time
II. Infectious Period 5
Diseases
Learning Objectives
Suggested Activities
1. State the function and components of
the immune system
2. State what is an immune system
3. Explain what immunity is and how it is
developed
5
(40 mins)
Resources
Scheme of work for Causes and Prevention of Infectious Diseases
Scheme of work for Infectious Diseases (Diseases and Community Health theme ~ Health Science Module)
Topic
Time
II. Infectious Period 6
Diseases
Learning Objectives
Suggested Activities
(40 mins)
Resources
1. State what vaccines are
2. Describe how vaccines work
3. Explain why booster shots may be
necessary for some vaccines
Scheme of work for Infectious Diseases (Diseases and Community Health theme ~ Health Science Module)
Topic
Time
II. Infectious Period 7
Diseases
Learning Objectives
Suggested Activities
1. Identify the international and local
organizations involved in the control
of infectious diseases
2. Describe how the local immunization
is implemented.
3. State the advantages and risks of
vaccination programs
6
(40 mins)
Resources
Lesson Plan for Causes and Prevention of Infectious Diseases
Lesson Plans for Infectious Diseases (Diseases and Community Health theme - Health Science Module)
Suggestions for teaching and activity sequence with time allocation
Lesson 1:
What are infectious diseases?
Sequence
(40 mins)
Content and Activity
Resources
Time
Motivation
Start by questioning the difference between viral and bacterial
infection
Teaching notes.
<5’
Theme Teaching
Illustrate the morphological differences among virus, bacteria, and
fungi.
Discuss their features according to the following questions below.
PowerPoint slides.
15’

What are the common diseases caused by these three
microorganisms?


Why antibiotics should not be used in viral infection?
Why “mad cow” (Bovine Spongiform Encephalopathy, or BSE)
disease is different from illness caused by the other
microbes?
Homework
assignment
Examine food, environmental, and personal hygiene at home, and
try to point out possible improvements.
Teaching notes.
5’
Consolidation
Discuss the causes of “chicken flu” (H5N1 virus or Avian Influenza)
Review
10’
and measures to control its spread.
Q&A
7
Lesson Plan for Causes and Prevention of Infectious Diseases
Lesson Plans for Infectious Diseases (Diseases and Community Health theme - Health Science Module)
Suggestions for teaching and activity sequence with time allocation
Lesson 2:
Microorganisms and Food – Video and Lab session (40 mins)
Sequence
Content and Activity
Resources
Time
Motivation
Start with providing a yogurt drink (e.g. Yakult) to every student, and Teaching notes.
discuss:
Yogurt drink
 What are the microorganisms used in the food industry (e.g.
soy sauce, cheese, wine, fermented tofu, etc.)?
 How the food industry applies pasteurization with the example
of fresh milk processing?
<10’
Video watching
Watch the videotape “Louis Pasteur’s legacy of hope” from the
Video tape, Video Player
20’
distributor Barr Media Group, Irwindale, CA, U.S.A.
and TV
Explain the laboratory safety precautions in the lab and the
sequence of the experiment that will be performed
Lab manual.
Lab session
preparation
8
10’
Lesson Plan for Causes and Prevention of Infectious Diseases
Lesson Plans for Infectious Diseases (Diseases and Community Health theme - Health Science Module)
Suggestions for teaching and activity sequence with time allocation
Lesson 3:
Food poisoning and preservation
Sequence
(40 mins)
Content and Activity
Resources
Time
10’
Follow-up
Homework and lab discussion (extra time after class is needed for
the students to interpret the experiment results under the
technician’s supervision)
Motivation
Ask the students about their experiences of food poisoning
Teaching notes.
<5’
Theme Teaching
Discuss various techniques for food preservation
 Introduce the principles of food preservation against
microorganism growth
PowerPoint slides,
newspaper
20’
Review and internet
10’

Consolidation
How does food poisoning happen?
Discuss the food and water supply of HK, and critique its safety
monitoring system.
Q&A
9
Lesson Plan for Causes and Prevention of Infectious Diseases
Lesson Plans for Infectious Diseases (Diseases and Community Health theme - Health Science Module)
Suggestions for teaching and activity sequence with time allocation
Lesson 4:
Pathogens and Defense Against Pathogens
Sequence
Motivation
Theme Teaching
(40 mins)
Content and Activity
Resources
5’
Ask students questions:
 What infectious diseases you have you had?
 What infectious diseases do you know?



What are the modes of transmission of infectious diseases?
What are the physical barriers our body uses to defend
against infection?
What are the chemical barriers our body uses to defend
Time
PowerPoint lecture
30’
against infection?
Consolidation
5’
Summary
Q&A
10
Lesson Plan for Causes and Prevention of Infectious Diseases
Lesson Plans for Infectious Diseases (Diseases and Community Health theme - Health Science Module)
Suggestions for teaching and activity sequence with time allocation
Lesson 5:
Immune System and Immunity (40 mins)
Sequence
Motivation
Theme Teaching
Consolidation
Content and Activity
Resources
3’
Ask students question:
 Do you think physical and chemical defense of our body
sufficient to protect us from infectious diseases? Why?




What is the immune system?
What are the components of the immune system?
What are immune response?
How is immunity against a disease developed?
CD Rom video of immune system and immune response
Q&A
11
Time
PowerPoint lecture
22’
About Immune System,
Corel Medical Series, 1997
15’
Lesson Plan for Causes and Prevention of Infectious Diseases
Lesson Plans for Infectious Diseases (Diseases and Community Health theme - Health Science Module)
Suggestions for teaching and activity sequence with time allocation
Lesson 6:
Vaccines and Vaccination
Sequence
Motivation
Theme Teaching
Consolidation
(40 mins)
Content and Activity
Resources
5’
Ask students question:
 What do you remember about your vaccine shots?




What are vaccines?
How vaccines produced?
How do vaccines work?
Why are multiple doses of vaccines sometimes needed?
Tell the story of Jenner or Salk in the development of vaccination
Q&A
12
Time
PowerPoint lecture
25’
Printed materials
10’
Lesson Plan for Causes and Prevention of Infectious Diseases
Lesson Plans for Infectious Diseases (Diseases and Community Health theme - Health Science Module)
Suggestions for teaching and activity sequence with time allocation
Lesson 7:
Control of Infectious Diseases
Sequence
Motivation
Theme Teaching
Content and Activity
Resources


What are the major international organizations in the control
of infectious diseases
What are the major local organizations in the control of
infectious diseases?
What is the value of vaccination in disease control?

What are the risks of vaccination?
Discussion: Pros and Cons of Vaccination-the lesson from the
Whooping cough vaccine
13
Time
5’
Ask students question:
 Name some of the recent outbreaks of infectious diseases

Consolidation
(40 mins)
PowerPoint lecture
20’
Printed materials
Internet
15’
Teacher/Student Notes for Infectious Diseases
PERIOD ONE
What Are Infectious Diseases?
Infectious diseases can be described as a parasitic relationship between
microbes and human. The pathogens find the suitable places and conditions in
human body to grow, reproduce, and cause damages to the host. Reservoirs
of infection are sites where pathogens can reproduce or stay alive until
transferring to hosts. The reservoirs can be humans, animals, insects, or
arachnids.
Humans may contract infection diseases by direct contact, inhalation,
ingestion, or injection of the pathogen. Some common diseases in the U.S. are
anthrax, rabies, ringworm, salmonellosis, etc. People contract an infectious
disease and are capable to transmit the disease to other humans. These
people are carriers of the disease, and they may or may not show any
symptoms at all. Inanimate reservoirs of infection can be air, soil, food, water,
fomites, etc.
Common diseases and their transmission routes
Transmission Routes
Examples
Remarks
Skin  Air  Respiratory tract Chickenpox, measles
Skin  Skin
Syphilis, Warts
Respiratory tract  Respiratory Colds. Influenza
tract
Shaking hands with a
carrier right after his
handling of a nose
discharge may also
contract the pathogen
Mouth
Gastroenteritis,
Hepatitis
14
Consuming food or
water contaminated with
fecal or soil matters
would contract the
diseases, and is
common in areas hit with
natural disasters like
flooding.
Genital Contact
AIDS, Gonorrhea
Blood Transfusion
AIDS, Hepatitis B
Vectors (insects, animal bites) Dengue fever,
Rabies
Some common infectious diseases in Hong Kong are listed in Table 1.
Teacher/Student Notes for Infectious Diseases
15
Teacher/Student Notes for Infectious Diseases
Why antibiotics should not be used in viral infection?
Antibiotics are designed to control bacteria, but it cannot deter the growth of
virus. Antibiotics are designed to attack or inhibit the bacterial structure or
enzymes that are absence in viruses.
Prescribing antibiotics to viral infection would encourage the growth of
antibiotic-resistant bacteria. This resistant strain may be disease causing,
and will be hard to contain. Over-prescription of antibiotics has been a major
concern lately, because antibiotic-resistant strain of bacteria emerges and
antibiotics can no longer contain these bacteria.
16
Teacher/Student Notes for Infectious Diseases
ADDITIONAL NOTES FOR TEACHERS
Photos of Pathogens
Disease causing:
Symptoms:
Disease causing:
Food Poisoning
Diarrhea
Stomach Ulcer
Disease causing:
17
Hepatitis B
18
Teacher/Student Notes for Infectious Diseases
Disease causing:
Disease causing:
Symptoms:
Sinusitis
Amebiasis
Chronic, mild diarrhea
with blood and mucus
Disease causing:
19
Ascariasis
20
PERIOD TWO
Microorganisms And The Food Industry
Microbes being used in food production
Microorganisms are also used for food production. Lactobacillus is used for
sour milk production (e.g. Yakult). The bacteria can partially digest the protein
and sugar in milk, so some lactose intolerant individuals may take the
pre-treated milk. Bacteria or fungi are also used for cheese flavoring. Yeasts
are fungi, and some are being used in food production, such as fermented
bean curds, bread, alcohol, etc.
Pasteurization
Pasteurization is a process that controls the microbe growth by raising the
temperature at 71oC for 15 seconds or 62 oC for 30 min followed by dropping
the temperature to 4oC in a short period of time. Pasteurization destroys all
yeasts, molds, disease-producing bacteria, and over 95% of the less harmful
strains of bacteria. The process can preserve the flavor of fresh milk and safe
to consume within 2 weeks.
Ultrahigh temperature treatment (UHT)
Ultrahigh temperature-treated milk is heated to 138 oC for 2 seconds, and it
can be stored for a much longer period of time because it is essentially free of
microbes.
21
Teacher Notes for Infectious Diseases
Lab Session
Possible laboratory topics
(Please choose the most feasible one, and the topics can be rotated each
year)
1.
Conducting an experiment on pasteurization using simple equipment
in laboratory. A lab technician inoculates bacteria in a culture flask
and let it grow overnight. The bacterial count is taken for every 10 oC
increase by streaking plates.
2.
Performing an experiment on the bacterial count on the hand surface
after an outing, before and after hand washing with soap. Thumbs are
dipped into a soften agar (beware of the temperature), and incubation
until bacterial colonies appear (at least one day).
22
PERIOD THREE
Teacher Notes for Infectious Diseases
Food Poisoning And Preservation
Control infectious diseases
Personal hygiene
Airborne contamination can be prevented by: covering the mouth and nose
when coughing or sneezing, dusting the floor and furniture with a damp cloth,
opening the room to fresh air (diluting the pathogen concentration in the air)
and sunlight (uv light – killing germs) when somebody has gotten infectious
disease.
Food hygiene
1. Keeping a clean kitchen (using detergent to clean utensils and
kitchen countertops),
2. Avoiding cross-contamination (keeping raw meat or any utensils
used for raw meat and cooked food in separate vicinities),
3. Keeping hot foods hot (cooked food always be kept at high
temperature), and cold foods cold (avoiding temperature abuse in
transport),
4. Washing hands before preparing or eating food.
5. Tap water coming from a contaminated source should be boiled to
rid the bacterial spores.
The mishandling of food by a caterer may cause food poisoning to a number
of people. Thousands of people were affected by food poisoning outbreaks
as shown in figure reported by the Department of Health in the years
between 1996-2000. Mishandling food in the caterers’ kitchen or in the
delivery route may cause these outbreaks. Raw food contamination may
23
also be a factor, such as salmonellosis (caused by salmonella, a
disease-causing bacteria, commonly found in eggs). This mishandling may
occur in a family setting as well, but the effect is not as noticeable.
Environment hygiene
Flies and mosquitoes are reservoirs of many common infectious diseases.
Keeping the environment clean would eradicate these vectors of disease.
24
Teacher Notes for Infectious Diseases
Food poisoning
Food poisoning is the diseases caused by the ingestion of contaminants,
mostly coming from microbes. The causative agents can be algae (ciguar
poison in fish), bacteria, fungi and protozoa. The symptoms can be vomiting
and diarrhea, and the incubation period (time from ingestion to the diseased
symptom occurred) can be ranged from 1 hour to 4 weeks depending on the
type of organism ingested.
The principles of food preservation
Food preservation uses physical or chemical means to control the growth of
microorganisms. Brines are salt solutions with high osmotic pressure that tie up the
water availability (example: salted fish). Sugar can be used instead of salt, but the
amount required is much greater for a comparable solute concentration in molarity
(example: condensed milk). Freezing can preserve some perishable food items;
however, it cannot kill the bacterial spores. Acidity (low pH) can be used to control
microbe growth (example: pickles). Some chemicals are added for preservation
(example: nitrite in ham, bacon, and lunch meat). Other techniques like canning – a
process that puts heat sterilized food item in an airtight compartment. Irradiation is a
new sterilizing technique that controls the growth of microbes by radiation.
25