1. Infection Control Lesson 1:34
Infection Control
Lesson 1:

2. Lesson Objectives
Upon completion of this lesson, students should be able to …
Define and spell the terms to learn for this chapter.
Describe the conditions required for the infection process to occur.

3. Critical Thinking Question
Why is an aseptic environment important?

4. The History of Asepsis
Methods for controlling the spread of infection were used before the infection process was understood
About 500 years ago, microorganisms known as germs were suspected to be the cause of diseases
About 100 years ago Semmelweiss, Lister, and Pasteur contributed solid research to our understanding of germ theory

5. The History of Asepsis
Today, there is a better understanding of germs and bacteria with the aid of high-powered microscopes and more specific laboratory procedures

6. Microorganisms: A Definition
Microorganisms (also called microbes) are living organisms that can only be seen with a microscope
Harmless microorganisms can be found on your skin, in your digestive tract, and in your respiratory tract
Microorganisms include protozoa, viruses, fungi, and bacteria

7. Scientific Fields of the Study of Microorganisms
Bacteriology
Study of bacteria
Mycology
Study of fungi
Protozoology
Study of protozoa
Virology
Study of viruses

8. Pathogens Harmful microorganisms are referred to as pathogens
E. Coli is a common example of a pathogen
Basic types of pathogens are listed below
Rickettsia
Virus
Protozoa
Bacteria
Fungi
Parasitic worms

9. How Microorganisms Grow
What is needed for a microorganism to grow?
Food
Moisture (e.g. mucous membranes)
Darkness
Appropriate temperature
Aerobic vs. anaerobic bacteria (those which need oxygen vs. those that do not)

10. Critical Thinking Question
What temperature is ideal for disease-producing pathogens?

11. How Pathogens are Transmitted
The chain of infection:
The reservoir host is the one which is first infected with and transfers the pathogen
The portal of exit is the means by which the pathogen exits the host (e.g. respiratory, gastrointestinal, urinary, and reproductive tracts, or an open wound)
The means of transmission is the way the pathogen moves between persons – Examples are a sneeze or touching a contaminated object

12. How Pathogens are Transmitted
The chain of infection:
The portal of entry is the means by which the pathogen enters the new host (e.g. respiratory, urinary, and reproductive tracts, skin and mucous membranes, or blood)
Finally, a susceptible host–like a person who cannot fight off the pathogen–is needed for infection to take place

13. Chain of Infection

14. Stages of the Infection Process
Invasion–pathogen enters body
Multiplication–pathogen multiplies
Incubation period–disease develops, but symptoms are not present
Prodromal period–mild symptoms appear; disease is very contagious
Acute period–symptoms are most severe
Recovery period–symptoms begin to subside

15. Critical Thinking Question
During which stage does a person stop being contagious?

16. Preventing the Spread of Infection
Natural defense mechanisms:
A healthy diet
Age (young children and elderly persons are most susceptible)
Sleep/rest
Natural barriers to infection:
Skin
Mucous membranes
Gastrointestinal tract
Lymphatic and blood systems

17. The Body’s Defense Mechanisms
The following help prevent the spread of infection:
Dietary intake of sufficient nutrients to promote health
Immune system–age can be a factor
Rest–getting adequate amounts sleep promotes health

18. The Body’s Defense Mechanisms
On the other hand, the mechanisms that promote the spread of infection are:
Other diseases in the body (e.g. diabetes, pneumonia)
Genetic inheritance of a disease that leaves the body more susceptible (e.g. cystic fibrosis)

19. Preventing the Spread of Infection
There are two ways to prevent the spread of infection:
Prevent the spread of causative microorganisms
Destroy the microorganisms

20. The Body’s Barriers to Infection
Skin
Mucous membranes–in the respiratory, urinary, digestive, and reproductive tracts
Gastrointestinal tract
Lymphatic system and blood system–both are involved with phagocytosis

21. Critical Thinking Question
How can these barriers be compromised?

22. Phagocytosis Phagocytosis What are leukocytes?
The process in which leukocytes actively fight pathogens
What are leukocytes?
For a video on phagocytosis go to MyHealthProfessionsKit.com or insert the DVD-Rom found in the back of your book.

23. The Antigen-Antibody Reaction and Immunity
What are antibodies?
The antigen-antibody reaction–occurs in response to the invasion of antigens
Immunity–the body’s natural defense mechanism includes:
Active acquired natural immunity
Active acquired artificial immunity
Passive acquired natural immunity
Passive acquired artificial immunity

24. Genetic and Acquired Immunity
Genetic immunity does not involve antibodies
Species immunity is passed on genetically and protects humans from certain animal diseases
Also protects animals from certain human diseases such as measles and influenza
Acquired immunity
Does involve the development of antibodies
May be acquired through active or passive means

25. Two Types of Active Immunity
Natural immunity
Person is born with this immunity
Artificial immunity
From an immunization or having had the disease such as with measles
Active immunity provides long-term immunity because the body produces its own antibodies

26. Active and Passive Immunity
Passive immunity develops when antibodies are artificially introduced into the body, and provides only temporary immunity
Active and passive immunity can be produced by both natural and acquired methods

27. Natural Active and Artificial Active Immunity
Natural active immunity develops as a result of having recovered from a disease such as measles, or being exposed to disease and becoming a carrier
Artificial active immunity is the result of receiving vaccinations with inactivated (dead) or attenuated (weakened) organisms

28. Types of Acquired Immunity
Active acquired natural
Acquired by having the disease, which results in production of antibodies and “memory cells” that respond when the antigen reappears again
Active acquired artificial
Acquired by administration of a vaccine that stimulates production of antibodies and “memory cells” to prevent that disease from occurring

29. Types of Acquired Immunity
Passive acquired natural
Acquired from someone else’s antibodies, such as from the mother to the fetus through the placenta or through breast milk
Passive acquired artificial
Produced by injecting a commercially prepared product to produce antibodies
Temporary protection is acquired from gamma globulin (examples: tetanus immune globulin, rabies antiserum)

30. The Inflammatory Process
The Acute inflammatory process:
Produces dilation of blood vessels due to:
Increased blood flow
Production of exudates
Invasion of monocytes and neutrophils
Symptoms of the process may be:
Local
Systemic

31. Critical Thinking Question
How is phagocytosis involved in the inflammatory process?

32. Cardinal Signs of Inflammation
Redness
Heat
Swelling
Pain

33. Questions? 33