2. Chapter 12 Infectious Diseases
Lesson 12.1 Infectious Diseases: What You Should Know Lesson 12.2 Transmission, Treatment, and Prevention of Infectious Diseases Lesson 12.3 Immunity to Infection

3. Monday, Jan 9

4. Infectious Diseases: What You Should Know
Lesson 12.1
Infectious Diseases: What You Should Know

6. Warm-Up Infectious Diseases
What are some causes of infectious diseases?
How are infectious diseases transmitted?
What are some ways of treating infectious diseases?
Courtesy of the Centers for Disease Control and Prevention

7. VIDEO
VIDEO: Protection from Infection

8. Infectious Disease Vocabulary
Germ Theory: a scientific concept stating that specific microorganisms cause specific diseases.
Infectious Diseases: are caused by microorganisms living in or on humans, animals, or plants.
Pathogens: Microorganisms that cause disease.

9. Infectious Diseases
Caused by microorganisms (pathogens) living in or on humans, animals, or plants
Also called communicable diseases because they can be transmitted from one living thing to another
shutterstock.com/wavebreakmedia

11. Signs and Symptoms of Disease
Signs are evidence of disease that can be outwardly observed or measured
Fever
An abnormal pulse
Symptoms are evidence of disease sensed by the sick person
Pain
Shortness of breath
shutterstock.com/bikeriderlondon

12. Lesson 12.1 Signs and Symptoms
For each medical scenario presented on the handout, differentiate between the signs and symptoms for each patient. If a patient does not exhibit either signs or symptoms, write “N/A” in the appropriate column.
Work individually to complete the worksheet.
We will discuss the answers in 10 minutes!

13. 1st Period

14. 6th Period

15. Tuesday, January 10 “A” Day

16. How Do Infections Cause Illness?
After pathogens enter the body, they grow, reproduce, and produce toxins
Toxins cause the familiar symptoms and signs of illness
Pain
Inflammation
Headache
shutterstock.com/S_L

17. Infections often follow stages in a recognizable pattern
Infections often follow stages in a recognizable pattern. What are the three common stages of an infection?
The incubation period is the time between the pathogen’s entrance into the body and the first appearance of symptoms.
In the clinical stage, signs and symptoms of a disease arise and are most prominent.
In the convalescent stage, signs and symptoms of a disease fade and a person is no longer contagious.

18. Profile of an Infection: Strep Throat

19. Microorganisms Include bacteria, viruses, fungi, and parasites
Are found everywhere and are typically invisible to the naked eye
Are diverse, specialized, and sophisticated
shutterstock.com/kurhan

20. Bacteria Single-celled organisms
Most are helpful and few of them cause disease
Most bacteria can grow independently outside of your cells
shutterstock.com/science photo

21. Viruses Pathogens that infect cells
Cannot reproduce or grow on their own
Very small, cannot be seen with ordinary microscopes
Cause the common cold and other illnesses
Ebola Virus
shutterstock.com/Subbotina Anna

22. Critical Thinking Viruses
Everyone knows about the common cold and influenza, which are notorious viral diseases.
What are some lesser known but important viral diseases?
Chickenpox.
Flu (influenza)
Herpes.
Human immunodeficiency virus (HIV/AIDS)
Human papillomavirus (HPV)
Infectious mononucleosis.
Mumps, measles and rubella.
Shingles.
Chickenpox.
Flu (influenza)
Herpes.
Human immunodeficiency virus (HIV/AIDS)
Human papillomavirus (HPV)
Infectious mononucleosis.
Mumps, measles and rubella.
Shingles.

23. Fungi Fungi include mushrooms, molds, and yeast
Few fungi cause disease and many are beneficial
A fungal infection, such as athlete’s foot, is called a mycosis
shutterstock.com/pedalist

24. Parasites: Protozoa and Worms
Parasites are organisms that must live inside or on another living thing
They cause damage and disease
Parasitic worms and protozoa infect a great number of people
shutterstock.com/PathDoc

25. Mosquitoes play a part in transmitting malaria.
Protozoa
Protozoa are single-celled organisms
Certain protozoa cause diseases
Malaria
Dysentery
Diarrhea
Mosquitoes play a part in transmitting malaria.
Courtesy of the Centers for Disease Control and Prevention

26. Worms
Parasitic worms are multicellular organisms with specialized tissues and organs
Methods of transmission
In water or food that has been contaminated with human waste
In undercooked meat and fish
shutterstock.com/moreimages

27. Transmission, Treatment, and Prevention of Infectious Diseases
Lesson 12.2
Transmission, Treatment, and Prevention of Infectious Diseases

28. Methods of Transmission
A method of transmission is simply the way a disease gets from one organism to another
Methods of transmission are classified as either direct or indirect
shutterstock.com/Siberia-Video and Photo

29. Direct Transmission
The exchange of infectious material from its origin to a susceptible individual
Direct contact
Sexually transmitted infections
Skin infections
Droplet spread
Sneezing
Coughing
shutterstock.com/JPC-PROD

30. Infected People
Many infectious diseases are spread through some form of contact with a person who has the disease.
The contact may be direct physical contact.
Infectious diseases can also spread through indirect contact.

31. Indirect Transmission
The exchange of infectious material to a susceptible person by a source that acts solely as a carrier
By animals
By contaminated objects
By airborne means
thinkstock.com/iStock/MikeLane45

32. Contaminated Objects
Some pathogens can survive for a period of time outside a person’s body.
These pathogens can be spread from person to person on objects such as
doorknobs
eating utensils
towels
needles used for body piercings and tattoos

33. Contaminated Food, Soil, or Water
Some pathogens are naturally present in food and soil.
Sometimes water and food become contaminated with pathogens from infected people.

34. What are some diseases that could be spread through contaminated water?
E. coli
Hepatitis
Typhoid
Cholera
Other parasitic infections

35. Occurrence of Infectious Disease
Diseases and other infections follow patterns
An epidemic infection occurs in unexpectedly large numbers
A pandemic infection affects an enormous number of people and spreads to much of the world
An endemic infection naturally occurs at low levels in a particular area
Emerging infectious diseases are new or increasing unexpectedly

36. Prevention of Infectious Diseases
Effective preventive measures can reduce the incidence of infectious diseases
Doctors recommend covering your nose and mouth with a tissue when coughing or sneezing
Vaccination can help stop the spread of an infectious disease
How Vaccinations Work
shutterstock.com/MSPhotographic

37. Myth or Fact?
Hand washing is not really important in preventing the spread of infectious diseases.
MYTH
Fact: Hand washing reduces the occurrence of infectious diseases that are transmitted by respiratory droplets, blood, or direct skin contact.
Fact: Alcohol-based hand rubs are very effective when soap and water are unavailable.

38. Food Sanitation
Used to prevent contamination during food processing, storage, and preparation
Avoid nonpasteurized drinks
Refrigerate and freeze perishables
Cook meat thoroughly
Wash vegetables and fruits
Use safe drinking water
shutterstock.com/Olesya Feketa

39. Treating Bacterial Infections
Antibiotics are substances that target and kill many kinds of pathogenic bacteria
Most antibiotics are prescription medications
A few antibiotics can be purchased at drugstores without a doctor’s prescription
shutterstock.com/Sheila Fitzgerald

40. Critical Thinking Antibiotic Resistance
Several strains of bacteria have developed antibiotic resistance and cannot be killed by antibiotics.
What are some steps that can help prevent antibiotic resistance?

41. Treating Viral Infections
There are few treatments for viral infections
Most medications target the symptoms and do not attack the virus
Medications can help keep the virus under control while the body fights the infection
shutterstock.com/Poznyakov

42. Lesson 12.3
Immunity to Infection

43. The First Line of Defense
The immune system continually defends the body against infection
The body’s skin (integumentary system) forms a nearly impenetrable barrier to pathogens
The body’s inner surfaces also have protection in the form of mucous membranes
shutterstock.com/Michaelpuche

44. Other System Defenses The respiratory system is protected by mucus
In the digestive system, mucus coats the throat, esophagus, stomach, intestines, and rectum
The regular flow of urine flushes microorganisms from the urinary system
Helpful bacteria occupy the large intestine and inhibit the growth of pathogens.
shutterstock.com/xrender

45. The Second Line of Defense
A phagocyte is a white blood cell that destroys microorganisms
Inflammation prepares the body to control and remove pathogens
Fever stimulates phagocytes and other white blood cells important for immunity
Click here for the “Events of Phagocytosis” animation
Body Scientific International, LLC.

46. The Third Line of Defense
The third defense system is made up of specialized cells and chemicals
T cells reside in the blood, lymph nodes, and spleen
A T-helper cell coordinates and stimulates the immune response
The T-cytotoxic cell attacks and kills cells in your body that have been infected with viruses
shutterstock.com/docstockmedia

47. Critical Thinking Promoting Resistance to Infection
Resistance to infectious diseases depends on a
healthy immune system and a healthy body.
What are some steps that you can take to promote good health?

48. B Cells and Antibodies
B cells also reside in the blood, lymph nodes, and spleen, where they make special chemicals called antibodies
An antibody sticks to a pathogen, labeling it as foreign to the body
This makes it easier for phagocytes to find and engulf the pathogens
Body Scientific International, LLC.

49. Immune System “Memory”
The B cells and T cells of the immune system remember encounters with pathogens
They can respond quickly to later exposures to these same pathogens
The immune response to later encounters can be so strong that you may not become ill at all
The immune system benefits from good nutrition and exercise
Some lifestyle choices, such as smoking, can suppress immunity

50. Your Immune System: Natural Born Killer

51. Monday, May 4 “C” Day