Communicable Diseases
Communicable Diseases

Definition
Caused by direct or indirect
spread of pathogens from one
person to another.
Pathogens

Definition
-Tiny living creatures that cause
disease.
Types of pathogens




Bacteria
Virus
Fungi
Protozoan
Bacteria
 (100
million will fit in a grain of
sand.)
 Most common of all pathogens.
 Most DO NOT cause disease.
 Reproduces through cell
division.
 Ex. Strep throat , lyme disease
Strep Throat
Bacteria Video
http://webcast.mediaondemand.com/library_video/20000901/27_bacteria_300.asx
Virus
All viruses are considered Parasites
 Smallest and simplest of
microorganisms.


Can only live on living cells-
tricks human cells to reproduce
more viruses.
 Reproduce until “cell burst”
 Examples- chicken pox, cold, flu,
measles, rabies, HIV/AIDS
Virus cont.
Highly
specific in types of cells they
invade.
Polio- nervous system
Common cold –respiratory system
Small pox, chicken pox, shinglesSkin cells.
Antibiotic drugs do not have an
affect on viruses.
Cell Burst
http://www.whfreeman.com/kuby/content/anm
/kb03an01.htm


Video
http://www.libraryvideo.com/streaming.asp?ms
cssid=GQ2BQAMMHCT78JEXX6WWGAQ4
EC2M3584&sku=N6639
How a virus reproduces

Cell Burst
Protozoan
Most are harmless.
 One celled organism
 Grows in water
 Multiples quickly in moist places
 Ex. Malaria

Fungi

Live off non-living things.

Molds, yeast, and mushrooms

Live in warm moist places.
 Ex. Locker room or mats

ex. Ring worm / athletes foot
Fungi
Athlete’s Foot
Ring Worm
A. Immune system- Body’s Primary
Defenses Against Diseases
(nonspecific resistance = will react the same
EVERY time a pathogen enters the body)
 Skin
 Mucus
Membrane
 Cilia
 Chemical
barriers – tears and saliva
 Reflexes- Blinking, coughing, and
sneezing.
Body’s Defense Against Communicable
 Skin
Disease
Most
important –
keeps out
harmful germs
Produces sweat
that kills some
types of
pathogens.
Body’s Defense Against Communicable
Disease
 Mucus
Membrane
Cells that line nose, mouth and
throat.
Produce mucus to trap germs
Body’s Defense Against Communicable
Disease
 Cilia
Wavelike
hairs that sweep out germs
Body’s Secondary Defenses
•Specific Resistance- more detailed then the primary
defense. Kills and keeps record of pathogens.
•Fever
•White Blood Cells
Body’s Defense Against Communicable
Disease
 Fever
Norm
temp. 98.6
When microorganisms multiply body
temp increases.
Temp. increase slows multiplying
Body’s Defense Against Communicable
Disease
 White
blood cells
Special cells that fight infection
Kill pathogens by surrounding and
swallowing
1. Lymphocytes = WBC’s (4 types)
Lymphocytes
4
types
 Killer T - attack
Are
sent to destroy or attack antigens
 Helper
T – control the strength and
quality of immune response
 B Cells –produce antibodies
 Macrophage- pac man like- take bite
of pathogen and sends back info. to
T-cells
How white blood cells work
Virus enters body system- indirect or direct
contact
 Macrophage- Bite virus and send antigen to Tcells
 Helper T cells – act as messenger calling B cells
 B Cells – create antibody to help kill pathogens
and remove pathogens (interlocking parts)
Virus can no longer invade body’s cells
Kept on file – body has immunity
 Killer T Cells – destroy virus

White Blood Cells
 Macrophage
–
 Pac-Man like garbage
collectors.
 Take bites of invaders
Antigens and Antibodies
 Antigens-
chemical code of pathogens.
Contains critical info. about the
pathogen
 Antibodies
1. Are created by B-Cells
2. Antibodies latch to pathogen. Fits
together like a lock and key. This
prevents the virus from entering cells
 Active
Immunity
 2 types
Natural – body gets disease & recovers
Recall immune response from
previous illness
Vaccination
Dead or weakened strain of virus
injected into you body.
Body then destroys virus and creates
antibodies against it.
Ways Disease Enter Body
Mouth
Break in skin
Eyes
Genitals
Nose

How diseases are spread
Direct contact –touching infected area
of person

Indirect contact-sneezing, coughing,
sharing personal items

Contact with animals and insects - bites
Other contact- eating contaminated
foods

Prevention for communicable
diseases
 Wash hand often!!!
 Cover mouth when sneezing or
coughing.
 Proper care of food
 Eat healthy and exercise
 Shower daily
 Avoid tobacco and drugs
White blood cells defend against germs
The immune system is made up of many different kinds
of white blood cells. White blood cells work together to
protect us against disease-causing germs.
Macrophages identify germs
When a germ invades our bodies, macrophages gobble up
the germ and display its surface shape, or antigen, for other
immune cells to see.
Helper T cells direct the defense
Helper T cells spot the foreign antigen on the
macrophage and begin to multiply. They alert other white
blood cells and direct the body's defense.
B cells make antibodies
B cells start to make chemicals called antibodies.
Antibodies lock onto foreign antigens making it easier
for other immune cells to destroy them.
Killer T cells destroy germs
Alerted by helper T cells, killer T cells multiply and
destroy the invading germs. Working together, our
white blood cells can usually destroy invading germs.
Problems with Immune System
 Immunodeficiency-
 System
not present or working
properly
 Some may be caused by medicines (
Chemotherapy)
 May be caused by infections (HIV,
AIDS)
Problems with Immune System
 Autoimmune
disorders
 Immune system mistakenly attacks
body’s healthy organs.
 Allergic Disorders
 System overreacts to exposure to
antigens in environment.
Common communicable diseases
 Common
cold –see handout
 Hepatitis-see
handout
 Mononucleosis-see
handout
REVIEW GAME

RULES1. two teams
 2. three strikes and your out
 3. Must get the question COMPLETELY right in
order to earn the points
 4. Two student compete to answer a non-related
health question. The winning student asks his team
if the want to play or pass……
 5. Object is the accumulate the most points

What are communicable disease?

Diseases that are passed from person to person
and caused by a pathogen.
Name the pathogen that causes the
following diseases?



HIV
Lyme disease
Ringworm
How does the following defense
work to help protects us from getting
sick




SkinMucus memberCiliaReflexes-
Answer to previous ?




Keeps out most pathogens, and produced sweat
to kill some pathogens
Produces mucus to trap pathogens
Wave-like hairs that sweep out germs
Blinking, coughing, sneezing
Name the four types of pathogens
that cause people to become ill?




Bacteria
Virus
Fungi
protozoa
Give three examples of how diseases
are passed through indirect contact?





Sneezing
Coughing
Sharing personal item, i.e. lip gloss, drinking
glass
Person to object
Animal to person, i.e. – deer tick
List three characteristics of a virus?





Smallest and simplest of all pathogens
Can only live and reproduce in a living cell
They will only attack specific parts of the body
Will eventually destroy the cell they invade
Tricks human cell to clone the virus
Name three ways pathogens can
enter the body?






Mouth
Eyes
Nose
Break in the skin
Genitals
ears
Name four types of white blood
cells?

Lymphocytes
A.
 B.
 C.
 D.

Killer T-Cells
Helper T-Cells
B- Cells
Macrophage (pac-man)
Name fours ways to prevent
communicable disease from
spreading?





Wash hands often
Cover mouth when sneezing or coughing
Proper food care- cook food thoroughly
Eat healthy and exercise
Shower daily