Disease Transmission and Infection Control Medical
Foundations
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Objectives Introduce microorganisms Become familiar with
infections and control measures Introduce the need for standards
and precautions Become familiar with sterile environments
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Introduction to Microorganisms Pathogenic microorganisms: cause
illness, infection, or disease Nonpathogenic microorganisms: help
keep a balance in the environment and in the body
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Microorganism Survival Most microorganisms that cause disease
Thrive in warm temperatures How warm is the human body? Need
moisture How much of the human body is made up of water? Prefer a
dark area to grow in Need food Some live on dead tissue
(saprophytes), some live on live tissue Some need oxygen (aerobic),
some do not need oxygen (anaerobic)
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Nonpathogenic Microorganisms Good microorganisms are used in a
variety of ways: examples? (P. 489) Buttermilk, fermenting alcohol,
making bread rise Where do nonpathogenic microorganisms live in
your body and what do they do?
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Types of Pathogens Bacteria One celled plants Classified by
shape and arrangement Causes strep throat, staph infections,
syphilis
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Protozoa One celled animals Found in water and soil
environments decayed material and contaminated water Cause amebic
dysentery and malaria Types of Pathogens
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Fungi Simple, low form of plant life May live on dead matter
Yeasts, molds Causes athletes foot, thrush, vaginitis, and serious
lung diseases Types of Pathogens
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Rickettsiae Parasitic microorganism Transmitted to humans
through the bite of lice, fleas, ticks, and mites Responsible for
some of the worlds worst epidemics Rocky Mountain spotted fever
Typhus
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Types of Pathogens Viruses Smallest microorganism, smaller than
bacteria Can only reproduce inside humans cells Causes common cold,
upper respiratory infections, smallpox, chickenpox, measles, mumps,
influenza, fever blisters Also cause HIV which can lead to
AIDS
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Additional Classifications Endogenous Originates inside the
body Exogenous Originates outside the body Nonsocomial An infection
acquired inside the hospital Opportunistic Infections that occur
when the bodys immune system is weak
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How Microorganisms Affect the Body Production of toxins
Staphylococcus produces enterotoxin that causes food poisoning =
fatigue, diarrhea, vomiting Tetanus bacilli produces a toxin that
attacks the central nervous system = damage, possible death Cell
invasion A protist can enter red blood cells, making them rupture =
chills and fever Allergic reactions Allergies = runny nose, watery
eyes, sneezing
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Chain of Infection
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How Microorganisms and Viruses Spread Direct Contact Indirect
Contact Airborne Oral Route Insects and Pests (Pg. 493)
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Disease Prevention Standard Precautions and Transmission-Based
Precautions were created to provide guidelines that prevent the
spread of microorganisms. Signs and SymptomsWhich is which?
Infections can be generalized or localized Affecting all of the
body Affecting one area of the body Give signs and symptoms of
each
