Notes #9: Infectious
Diseases
Immune System Week 2:
Diseases
Infectious Diseases
Diseases caused by a virus, bacterium, protist
or fungus and are spread from an infected
organism or the environment to another
organism
Biological Vector: disease carrying organism
(rats, birds, dogs, cats, mosquitoes, fleas, flies)
People can be carriers too!
Surgery Through History
Past: bloody aprons, dirty tools
and street clothes were
commonplace
 Present: disinfectants,
sterilized tools, antiseptics and
protective (sterile) clothing.
 Joseph Lister: one of the first
surgeons to promote keeping
things clean during surgery.

Remember from Notes 8…
Elbow Partners:
 Tell your partner: What is a pathogen?
 Have them tell you: 1 example of a
pathogen.

If you have only 3 people at your table,
they can answer either question again, in
their own words.
Continued…
Pathogen: a microscopic organism that causes
communicable diseases.
4 Types of pathogens:
1. Viruses: tiny nonliving particles that invade and
take over healthy cells. THEY CANNOT LIVE
WITHOUT A HOST TO INFECT. Hard to kill
since not alive.
2. Bacteria: extremely small, single-celled
organisms with no cell nucleus. CAN LIVE ON
SURFACES. Easier to kill than viruses.
3. Protozoa: single-celled organisms.
4. Fungi: primitive single- or many-celled
organism that cannot make their own food.
How Pathogens are Spread

6 common ways to spread pathogens:
1. Direct contact (touching)
2. Indirect contact (breathing, clothing/sheets,
door handles, etc.)
3. Contact with someone else’s blood
4. Sexual Contact
5. Eating or Drinking contaminated food or
water
6. Contact with animals or insects
Elbow Partners

Discuss with your neighbor why people
get more sick in winter, when its cold out?
Hint: It has very little to do with the
weather.

Be ready to share- the equity cards will
decide…
Answer
People stay inside more when its cold out,
this means more sick people are around
you all winter!
 Also, scientists just finished a study in
December saying that when its cold, your
nose and throat mucus is thinner so its
less able to stick and grab onto
pathogens, leaving them free to get you
sick! 

Lesson 3: Common Communicable
Diseases
Cold VIRUS
 Influenza (flu) VIRUS: a communicable
disease characterized by fever, chills,
fatigue, headache, muscle aches, and
respiratory symptoms.

Chicken Pox, Measles, and Mumps

Contagious period: the length of time that
a particular disease can be spread from
person to person.
Other Communicable Diseases
Mononucleosis
 Hepatitis
 Tuberculosis
 Pneumonia
 Strep Throat
 STDs (sexually transmitted)

– Bacterial (curable)
 Gonorrhea, Chlamydia, Syphilis
– Viral (have whole life)
 Genital Herpes
Elbow Partners
Tell him/her the 6 ways you now know
that pathogens are spread.
 THEN have him/her tell you what
people can do to prevent the spread.

Lesson 4: Preventing the Spread of
Disease
Hygiene: AKA Cleanliness. Helps limit the
number of pathogens you encounter.
 Protect yourself and others:

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Avoid close contact with someone sick
Don’t share eating utensils
Wash your hands
Keep hands away from mouth, eyes, nose and cuts
Handle food safely
Wipe counters
Empty trash often
Keep Pets clean
Healthful Lifestyle
Eat a balanced diet
 Bathe and shower regularly
 Avoid tobacco use
 Get 8-9 hours of sleep each night
 Rest when you get sick
 Learn to manage stress
 Visit the doctor on a regular routine

Elbow Partners
Tell your partner some ways to keep
your hands clean and what that can do for
you.
 Then have him/her tell you which they
think is better at killing pathogens on your
hands: Washing your hands or using hand
sanitizer? Do you both agree?

TPS: Washing your Hands to
stop the spread of pathogens
How does soap actually work? What does
it do?
 https://www.youtube.com/watch?v=ga2ff
1nO0uo

Pathogen Lab (Bread):
Part A: Does washing your
hands remove pathogens?
Part B: Which removes
pathogens better? Soap or hand
sanitizer?
LAB WS: Make a hypothesis for
Part A and another for Part B

Then make observations on the bread
slices under Day 5.
Lesson 5: Sexually Transmitted
Diseases (STDs)

Sexually Transmitted Diseases: infections
that are spread from person to person
through sexual contact.
STDs
Chlamydia
 Genital Warts
 Genital Herpes
 Trichomoniasis
 Gonorrhea
 Syphilis
 Hepatitis B

WARNING
***Some STDs are curable with strong
medicines from a doctor, while others you
can never get rid of your entire life***
Abstinence from Sexual Activity
Saying no and avoiding sexual activity.
 This is the only 100% effective way of
preventing the spread of STDs.
 That’s right- condoms are only 63-97%
effective.

Lesson 6: HIV and AIDs
HIV or human immunodeficiency virus:
the virus that cause AIDs.
 AIDs or acquired immunodeficiency
syndrome: a disease that interferes with
the body’s ability to fight infection.

How HIV is Spread
Having any form of sexual intercourse
with an infected person
 Using contaminated needles
 Babies can get if from their mother (if
infected)

How HIV is Not Spread

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Swimming in pool with infected person
Sharing eating utensils with infected person
Breathing the air near infected person
Donating blood
Being bitten by mosquito after biting infected
person
Hugging or shaking hands with infected person
Using same shower
Sharing sports equipment
Abstinence and HIV
AIDs has no cure and you can protect
yourself from getting HIV by staying away
from unprotected sexual activity or
abstaining from sex.
 Abstinence is the only 100% sure way to
avoid infections and pregnancy.

Abstinence
is the only 100%
sure way to avoid infections
and pregnancy.
Elbow Partners
You have 20 seconds to:
 In your best doctor voice, tell your partner
why showing abstinence is the safest
choice for avoiding STDs and pregnancy.
Use as many facts as you can- because
doctors love facts.
 Then have your partner try it back to see
whose was better 


Put these in your notes tab- great job
today!
Let’s play a game!

Blank piece of paper: Keep a record of
who you shake hands with in the time
limit. You have 2 minutes to shake hands!
If your name is called, stand up…
Our patient zero is ______________;
stand up. You were sick with a virus the
whole time!
 Read the 5 people you shook hands with...
Because they are infected, too. They
should stand up.
 They will read the 5 people they shook
hands AFTER PATIENT ZERO with who are
also now infected.
 Repeat steps 2 & 3
