Chapter 24
Communicable Diseases
Lesson 1 – What Are Communicable Diseases?
1. What is a communicable disease?
• A disease that is spread from one living thing to
another or through the environment.
2. Why is it important to know how
communicable diseases are spread?
• To reduce your risk of getting them.
Lesson 1 -continued
3. Provide a brief description of and name 2 diseases caused
by each of the following pathogens.
Viruses
• Pieces of genetic material surrounded by a protein coat.
• Common cold and influenza (flu).
Bacteria
• Single-celled microorganisms that live almost anywhere on
earth.
• Strep throat and Lyme disease.
Lesson 1 - continued
Protozoans
• Single-celled organisms that are larger and more
complex than bacteria.
• Malaria and amoebic dysentery.
Fungi
• Plant-like organisms such as molds and yeast.
• Athlete’s foot and ringworm.
Lesson 1 - continued
Rickettsias
•Pathogens that resemble bacteria. Often
enter humans through the bite of an insect.
•Typhus and Rocky Mountain Spotted Fever.
Examples
Lesson 1 - continued
4. Describe 3 ways a communicable disease can
be transmitted by INDIRECT CONTACT.
• Contaminated objects – door handles, desks,
and computer keyboards.
• Vectors – tick or mosquito.
• Water and food – undercooked food and
contaminated water supply.
Lesson 1 - continued
5. How is airborne transmission of pathogens
different from transmission by direct contact?
• DIRECT CONTACT – Touching, biting, and kissing.
Also, sneezing and coughing can spray a nearby
person.
• Airborne transmission – Pathogens don’t settle
quickly on surfaces/may travel long distances.
Lesson 1 - continued
6. What is the most effective way to prevent
the spread of communicable disease?
•Washing hands.
•Handling food properly.
Lesson 1 - continued
7. List 5 measures that will help prevent the spread of
foodborne illness.
• Always wash hands before handling food.
• Use paper towels in place of dish cloths/sponges.
• Keep surfaces and equipment clean.
• Separate raw meat and other food.
• Chill cold and leftover food quickly.
Lesson 1 - continued
8. How does a balanced diet and regular
exercise help prevent the spread of
disease?
•Reduces your risk of getting/spreading
diseases.
9. What is the role of stress in the spread of
disease?
•Makes you vulnerable to illness.
Lesson 2 – Preventing Communicable Diseases
1. What is the immune system?
• Network of cells, tissues, organs, and chemicals that fights
off pathogens.
2. How do physical barriers protect the body from
pathogens? How do chemical barriers protect the body
from pathogens?
Physical barriers
• Block pathogens from invading your body.
Chemical barriers
• Destroy pathogens.
Lesson 2 - continued
3. How does the inflammatory response involved
in fighting pathogens?
• Prevent further tissue injury and halt invading
pathogens.
4. Complete the following outline of the body’s
specific defenses.
Lymphocytes
A. T cells
Lesson 2 - continued
1. Helper T cells – trigger the production of B cells and
killer T cells.
2. Killer T cells - attack and destroy infected body cells.
3. Suppressor T cells - coordinate T cell activity, turn off
helper T cells.
B. B cells – produce antibodies.
C. Memory Lymphocytes – circulate in the blood
stream for years, provide long-term immunity.
Lesson 2 - continued
5. What is the difference between active and passive
immunity?
• Active immunity – body produces its own antibodies,
exposed to invading pathogens or a vaccine.
• Passive immunity – when a person receives antibodies
from another person. For example, mother passes to
child during pregnancy.
Lesson 2 - continued
6. List 5 behaviors that will help you maintain a healthy
immune system.
• Eat nutritious meals/drink 6 to 8 glasses of water each day.
• Get plenty of rest.
• Get plenty of physical activity /avoid sharing personal items.
• Avoid tobacco, other drugs, and sexual contact.
• Keep immunizations up to date.
Lesson 2 - continued
7. List the 4 types of vaccines mentioned in the lesson.
• Live-virus vaccines.
• Killed-virus vaccines.
• Toxoids.
• New and second – generation vaccines.
8. How do vaccines benefit people other than those who received
vaccination? Does this benefit exist for all communicable diseases?
• You cannot get a disease if you have been vaccinated……you cannot
spread the disease to other people.
• Only true for diseases that are spread person to person.
Lesson 2 - continued
8. How do vaccines benefit people other than those who
received vaccination? Does this benefit exist for all
communicable diseases?
• You cannot get a disease if you have been vaccinated……you
cannot spread the disease to other people.
• Only true for diseases that are spread person to person.
9. In what way do toxoids prevent disease?
• Use inactivated toxins from pathogens to stimulate the
production of antibodies.
Lesson 3 – Common Communicable Diseases
1. Write a brief summary of the symptoms and treatments for each of the
following respiratory infections.
Common cold (viral infection)
• Running nose, sneezing and sore throat.
• Treatment is for relief of symptoms, use ibuprofen instead of aspirin.
Influenza (viral infection)
• High fever, fatigue, head ache, muscle aches, and cough.
• Anti-viral drugs are available but must be as soon as 1st symptoms arise.
Pneumonia (viral and bacterial)
• Similar to those of the flu.
• If bacterial, can be treated with antibiotics. If viral, anti-viral drugs can be
used.
Lesson 3 - continued
Strep Throat (bacterial infection)
• Sore throat, fever, and enlarged lymph nodes in the neck.
• Treated with antibiotics.
Tuberculosis
• Fatigue, coughing (sometimes bloody), fever, night sweats, and
weight loss.
• Some strains of TB are drug resistant, so doctors use different
antibiotics.
2. What is hepatitis?
• It is an inflammation of the liver.
Lesson 3 - continued
3. What is the mode of transportation for the hepatitis A virus? The
hepatitis B virus? The hepatitis C virus?
Hepatitis A
• Most commonly spread through contact with feces of an infected
person.
Hepatitis B
• Found in most bodily fluids of an infected person.
Hepatitis C
• Direct contact with infected blood through dirty needles shared by
drug users.
Lesson 3 - continued
4. Describe 3 factors that contribute to emerging infections.
• Transport across borders.
• Population movement.
• Resistance to antibiotics.
• Changes in food technology.
• Agents of bioterrorism.