Warm-Up

Write about the last time you had a cold.
Include the list of symptoms you experienced.
Explain how you think you caught the cold
and what you did to treat in.
Communicable
Disease Prevention
Lesson 31
Objectives
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Examine the effects of health behaviors on skin
Examine the relationship between health behaviors and the ways
that communicable diseases are spread
Develop and analyze strategies related to the prevention of
communicable and non-communicable diseases
Identify available health related services in the community that
provide vaccines and information related to disease prevention
Identify the causes, transmission, symptoms and treatment of
several communicable diseases
Discuss how public health policies and government regulations
influence health promotion and disease prevention
Communicable Diseases
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Disease that is spread from one living thing to
another or through the environment
Causes:
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Pathogen: organism that causes disease
 Viruses
 Bacteria
 Fungi
 Protozoans
 Rickettsias
Infection: condition that occurs when pathogens
enter the body, multiply and damage body cell
Viruses
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Pieces of genetic material surrounded by a
protein coat
Need living cells to reproduce
Invade all known forms of life
After the virus penetrates a it takes control of
the cell to manufacture more viruses
Antibiotics do not work against viruses
Bacteria
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Single celled microorganisms
Live almost everywhere on earth
Most are harmless
Multiply through cell division in the body
Some produce a toxin
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Substance that kills cells or interferes with their
functions
Can be treated with antibiotics
Other Types of Pathogens
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Fungi
 Plantlike organisms
 Molds
 Yeasts
 Some can cause diseases of the skin, mucous membranes or the
lungs
Protozoans
 Single-celled organisms that are larger and more complex than
bacteria
Rickettsias
 Pathogens that resemble bacteria
 Multiply by invading the cells of another life form
 Often enter humans through the bites of insects, such as fleas or
lice
Figure 24.1 Pg 623 Diseases
by Type of Pathogen
How Communicable Diseases
are Transmitted
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Direct Contact: spread by contact with an infected person, animal, or
something in the environment
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Touching
Biting
Kissing
Sexual contact
Sneezing
Coughing
Indirect Contact: spread indirectly, without being close to an infected
person
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Contaminated objects: objects that have infectious discharges or secretions,
such as a table that someone ahs sneezed on
Vectors: organism, usually an arthropod, such as a tick, that carries and
transmits pathogens to humans or other animals
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common vectors include flies, mosquitoes and ticks
Water and Food
Airborne Transmission
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Pathogens from a sneeze or cough may float in the air for a long time over
long distances
Chicken pox, tuberculosis, influenza and anthrax can be spread this way
Preventing Communicable
Diseases
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Physical and
chemical
barriers
make up
your body’s
first line of
defense
Figure 24.1
Pg 628
Skin
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Epidermis: outer, thinner layer of skin that is
composed of living and dead cells
Dermis: thicker layer of skin beneath the epidermis
made up of connective tissue and containing blood
vessels and nerves
The skin is the first line of defense against many
pathogens, however it can be compromised by
various actions
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Exposure to sun
Body piercing
tattooing
Protecting Your Skin
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Always wear sunscreen on exposed areas
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Use a SPF that is 15 or higher
Use a sunscreen that protects against both UVA
and UVB rays
Apply 15 to 30 minutes before going outside
Use even on cloudy days and when participating
in winter sports
Body Piercing and Tattooing
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Result in the physical barrier of the skin being
broken
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Possibility of bacteria or viruses entering the body
increases
Transfer of blood borne pathogens through the use of nonsterile needles
 Hepatitis B
 Hepatitis C
 HIV
If considering getting a piercing or a tattoo consider
long term consequences. Make sure you go to a
reputable and clean place to decrease chances of
disease or infection
Remember, your skin protects you, so harming your
skin can harm your entire body…
The Immune System
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Network of cells, tissues, organs and
chemicals that fights off pathogens
2 major defense strategies
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Inflammatory response: reaction to tissue damage
caused by injury or infection (general response)
Specific defenses: work against particular
pathogens
Inflammatory Response
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In response to invasion by microorganisms and to tissue damage
Blood vessels near the site expand, allowing more blood flow to
the area
Fluid and cells from the bloodstream leak into the area
Collection of fluid and white blood cells causes swelling and pain
because of pressure on nerve endings
 Phagocyte: white blood cell that attacks invading pathogens
 Phagocytes engulf pathogens and then destroy them with
chemicals
 Pus may collect at the site
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Collection of dead white blood cells and damaged tissues
Specific defenses are activated in an effort to prevent this same
infection from occurring again
Specific Defenses
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React to invasion as a result of the body’s
ability to recognize certain pathogens and
destroy them
Antigen: substance that is capable of
triggering an immune response
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During the immune response certain types of
white blood cells react to these antigens
Lymphocytes
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Specialized white blood cell that coordinates and performs many
of the functions of specific immunity
 T Cells
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Helper T Cells
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Killer T Cells
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Attack and destroy infected body cells
Don’t attack the pathogen, only the infected cells
Suppressor T Cells
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Trigger the production of B cells and killer T cells
Coordinate the activities of other T cells
“turn off” helper T cells when infection has been cleared
B Cells
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Produce antibodies
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Proteins that act against specific antigens
Attach to foreign antigens to mark them for destruction
Destroy invading pathogens
Block viruses from entering body cells
Memory Lymphocytes
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Some T cells and B cells that have been activated by antigens become
memory cells
Recognize a former invader
Attack viruses immediately, protecting you from becoming ill
Active Immunity
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Immunity your body develops to protect you from diseases
Naturally acquired when your body is exposed to antigens from invading
pathogens
Artificially acquired immunity develops in response to a vaccine
Some immunities last a lifetime, but others need to be repeated to maintain
immunity
Passive Immunity
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Receiving antibodies from another person or animal
Short lived immunity, lasting only weeks to months
Natural passive immunity occurs when antibodies pass from mother to child
during pregnancy or while nursing
Artificial passive immunity results fro the injection of antibodies produce by
an animal or a human who is immune to the disease
Lymphatic System: Figure 24.4
pg 632
Care of the Immune System
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Eat healthy, making sure to consume nutrient rich
foods
Get plenty of rest
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Get about an hour of physical activity every day
Avoid sharing personal items
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Towels, toothbrushes, make up
Avoid tobacco, alcohol and other drugs
Avoid sexual contact
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Fatigue reduces the effectiveness of the immune system
Some STDs, such as HIVE actually destroy the immune
system
Keep immunizations up to date
Vaccines to Aid the Body’s
Defenses
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Live-Virus Vaccines
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Killer-Virus Vaccines
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Use inactivated pathogens
Even though they are dead, the organism still stimulate as immune response,
producing antibodies
Vaccines for the flu, polio, hepatitis A, rabies, cholera and the plague are produced in
this way
Toxoids
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Made from pathogens grown under special laboratory condition to make them lose
most of their disease causing properties
The weakened virus can still stimulate the production of antibodies
Vaccines for measles, mumps, rubella and chick pox are produced in this way
Inactivated toxins from pathogens
Used to stimulate the production of antibodies
Many pathogens aren’t harmful themselves, but the toxins they produce are
Tetanus and diptheria immunizations work in this way
New and second generation vaccines
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Being developed by scientist using new technologies
Vaccine for hepatitis B is made from genetically altered yeast cells
Common Communicable
Diseases
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Respiratory Infections
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Can occur anywhere from the nose to the alveoli of the
lungs
Most caused by viruses or bacteria
Common respiratory infections include:
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Common cold
Influenza
Pneumonia
Strep throat
tuberculosis
The Common Cold
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Viral infection
Causes inflammation of the mucous membranes
that line the nose and throat
Symptoms:
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Runny nose
Sneezing
Sore throat
No cure
Treatments may help to relieve symptoms, and most
cold will clear up in a week or so
Influenza
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The flu
Viral infection of the respiratory tract
Most often spread through airborne transmission
Symptoms:
 High fever
 Fatigue
 Headache
 Muscle aches
 Cough
Antiviral drugs for treatment are available, but need to be given
as soon as the illness arises
Flu vaccination is available in a shot or nasal mist
The Flu can lead to pneumona
Pneumonia
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An infection of the lungs in which the air sacs fill with
pus and other liquid
One of the top 10 causes of death in the US along
with the flu
Viral pneumonia is relatively short-lived and
produces symptoms similar to those of the flu
Bacterial pneumonia can be treated with antibiotics
Bacteria that cause pneumonia are often present in
healthy throats, but when the body defenses are
weakened they may get into the lungs and multiply
Strep Throat
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Bacterial infection spread by direct contact
Symptoms
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Sore throat
Fever
Enlarged lymph nodes
Untreated strep throat can lead to serious
complications, including inflammation of the kidneys
and rheumatic fever, which can cause permanent
heart damage
Treated with anitbiotics
Tuberculosis
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“TB”
Bacterial disease that usually attacks the lungs
Spread through the air when a person with the
disease coughs or sneezes
Most people who are infected carry the bacteria in
their lungs but never develop the disease
Some strains have developed resistance to
antibiotics
Hepatitis
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A
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Another one of the top 10 communicable diseases report in the US
Most commonly spread through contact with feces of an infected person
Symptoms
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B
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More serious than hepatitis A
Found in bodily fluids of an infected person
Often transmitted through sexual contact
Most people never experience symptoms, however, serious symptoms can occur
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Fever
Nausea
Vomiting
Fatigue
Abdominal pain
Jaundice: yellowing of the skin and eyes
Severe liver damage including liver failure and cirrhosis (scarring) of the liver
May be responsible for up to 80% of all cases of liver cancer worldwide
C
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Most common chronic blood-borne infection in the US
Transmitted by direct contact with infected blood
Can lead to chronic liver disease, liver cancer and liver failure
Leading reason for liver transplants in the US
No cure
Other Common Communicable
Diseases: Figure 24.5 pg 640
Emerging Infections
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Communicable disease whose incidence in humans has
increased within the past two decades or threatens to increase in
the near future
Factors contributing to the development of emerging infections
include:
 Transport across borders
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Infected people and animals carry pathogens from regions to region
Population movement
Resistance to antibiotics
Changes in food technology
Agents of bioterrorism
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Because of the ease and frequency of travel, a contagious bioterrorist
agent can spread rapidly from country to country
Strategies for Preventing
Communicable Disease
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Wash Hands
Handle Food Properly
Eat a balanced diet
Avoid sharing utensils
Avoid unnecessary contact with people who are ill
Take care of yourself when you are ill
Get vaccinated against particular disease as
recommenced by your physician
Abstain from sexual activity
Learn to manage stress