What Are Communicable
Diseases?
WHAT IS THE BEST WAY TO PREVENT
SPREADING COMMUNICABLE DISEASES
 Communicable disease:
A disease that is spread from one living thing to another or
through the environment.
Causes of Communicable Diseases
 Pathogen An organism that causes a disease
 Common pathogens….

viruses, bacteria, fungi, protozoans, and rickettsias
 Infectioncondition that occurs when pathogens enter the body, multiply,
and damage body cells
 Disease develops
Viruses
 Pieces of genetic material surrounded by a protein
coating
 The nuclear (chromosomal) and cytoplasmic
(mitochondrial and chloroplast) material that plays a
fundamental role in determining the nature of all cell
substances, cell structures, and cell effects; the genes have
properties of self-propagation and variation.
 Alone they are inactive
 Need living cells to produce
 Includes all forms of life
 Once inside a host cell virus makes more viruses
 Viruses usually kill the host cell and take over other
cells
 Usually “run their course”
 Antibiotics do not work
 Common viruses
 Common cold, flu, AIDs, chicken pox, measles
Bacteria
 Single-celled microorganisms- are everywhere!
 Some harmless
 Some helpful- in digestive system they help digestive
food and certain vitamins
 When inside your body they multiply- cell division
 Some bacteria produce toxin- kills cells or interferes
with their functions

Tetanus- Infection generally occurs through wound
contamination and often involves a cut or deep puncture
wound
 Bacteria and viruses can be killed by immune system
 Most bacterial infections are treated with antibiotics
 Common:
 Strep throat, lyme disease, tuberculosis,
Fungi
 Plantlike organisms
 Molds and yeast
 Disease of skin, mucosal membrane, or lungs
 Athlete’s foot
Protozoans
 Single-celled organisms larger and more complex
than bacteria
 Most are harmless
 Some can cause disease especially in people with
weakened immune systems
Rickettsias
 Similar to bacteria
 Often from insect bites (fleas and lice)
 Rocky Mountain Fever most common
How They are Transmitted
Direct Contact
 Touching, biting, kissing, and sexual contact
 Sneezing or coughing- sprays infected saliva or
mucus
 Mother transmits infections to unborn child
Indirect Contact
 Contaminated object



germs move onto an object- someone touches the object and
picks up the germs
Examples..
Wash hands to prevent picking up infections
 Vectors
 An organism that carries and transmits pathogens to humans
or other animals
 Examples..
 Mosquitoes- malaria, Ticks- Lyme disease
 Water and Food
 Carless handling, cooking, and storage of food
 Water contaminate with pathogens
Airborne Transmission
 Pathogens travel in the air from a sneeze or cough
 Long distances
 Chicken pox, influenza, tuberculosis
Preventing the Spread of Disease
Washing Hands
 Most effective way to prevent spread of disease
 When….
 Before preparing food and eating
 After the bathroom
 Before contacts
 After touching animals
 When around an infected person
Handle food properly
 Cook properly
 Chill leftover to proper temp
 Separate raw meat from other foods
Other Measures
 Eat balanced diet
 Avoid use of drugs
 Avoid eating and drinking after people
 Avoid contact with infected people
 Keep vaccines up to date
 Manage stress