JOURNAL
12-13-07
Write a brief paragraph describing the
symptoms you experienced the last
time you had a cold, and explain how
you think you caught the cold.
COMMUNICABLE
DISEASES
Health 10
December 13, 2007
Communicable Diseases
A disease that is spread from one living thing to
another or through the environment.
Pathogens – organisms that cause disease.
Common pathogens
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Viruses
Bacteria
Fungi
Protozoans
Ricettsias
Infection – pathogens enter the body, multiply,
and damage body cells.
Viruses
 Pieces of genetic material surrounded by
a protein coat.
 Need living cells to reproduce.
 Penetrates a cell,
then takes control
of the cell to create
more viruses.
 Usually run their course and are
eventually killed by the immune system.
Bacteria
 Single-celled microorganisms that live most
everywhere on earth.
 When bacteria enter the body,
they multiply through cell
division.
 Some produce a toxin.

A substance that kills cells
or interferes with their
functions.
 Destroyed by immune system, but most can be
treated with antibiotics as well.
Other types of Pathogens…
YEAST - plantlike organisms, such as molds and
yeasts. Some types cause diseases of the skin
and diseases of the mucous membranes.
PROTOZOANS – single-celled organisms that
are larger and more complex than bacteria.
RICKETTSIAS – Pathogens that resemble
bacteria. Enter the bodies of humans through
bites of insects.
Diseases by Type of Pathogen
How do they spread?
1. Direct Physical Contact
 Touching, biting, kissing, and sexual contact.
 Sneezing and coughing can spray infectious
droplets of saliva or mucus into a nearby
person’s eyes, nose, or mouth.
 Pregnant woman passing it to the child
 Tetanus from a puncture wound
How do they spread?
2. Indirect contact
 Contact with a contaminated object.

Inanimate objects can become contaminated with
infectious discharges or secretions.
 Contact with animals. Also called vectors.
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Vectors are organisms that carry and transmit pathogens
to humans or other animals.
Flies, mosquitoes, ticks.
 Contact with water and food.

Careless handling and storage of food are major sources
of contamination and illness.
How do they spread?
3. Airborne transmission
 Different from direct contact because the
pathogens do not settle quickly on surfaces.
 Examples:
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Chicken pox
Influenza
Preventing Communicable Diseases
Hand-washing is the single most
effective strategy for preventing the spread of
disease.
Wash your hands…
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Before you prepare food,
Before you eat, and,
After you use the bathroom.
Handle Food Properly
Food borne illness occurs in places where food
is handled improperly.
Always wash your hands before you handle
food.
Use paper towels, not dishcloths or sponges, to
keep surfaces clean.
Separate raw meat from other foods.
Cook food to it’s proper temperature.
Chill cold and leftover foods quickly.
Other prevention strategies:
Eat a balanced diet; participate in regular exercise;
avoid tobacco, alcohol, and other drugs.
Avoid sharing eating utensils.
Avoid unnecessary contact with people who are ill.
Cover your mouth when you cough or sneeze.
Use mosquito repellent when outdoors.
Get proper vaccinations.
Learn to manage stress.