Transcript Disease Transmission

Unit 2
Disease
Transmission
Disease Transmission
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INFECTIOUS DISEASE:
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An infectious disease occurs when a
microorganism in the body multiplies and
causes damage to the tissues.
Disease Transmission
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Differences between pathogenic &
nonpathogenic
Pathogenic: disease causing
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Nonpathogenic: non-disease causing
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Microorganisms that cause disease are
PATHOGENS
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Disease transmission
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Opportunistic pathogens:
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Cause diseases only when given a special
opportunity to enter deeper tissues of the body
or to accumulate to levels that can harm the
body
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They wait for the opportunity to cause disease.
Types of Infectious Diseases:
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ENDOGENOUS: caused by microbes
normally present on or in the body without
causing harm
But something happens that allows them to
express this disease-producing potential
Examples: dental caries, periodontal disease
Opportunistic- endogenous
Types of Infectious Diseases:
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EXOGENOUS: caused by microbes that are
not normally present on or in the body
But contaminate the body from the outside
Examples: Strep Throat, Measles,
“Common” Cold, Hepatitis (various forms),
HIV-Human immunodeficiency virus
Steps in development of
Infectious Disease:
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Source of Microorganism
Escape of microorganism from the source
Spread of microorganisms to new person
Entry of microorganism into new person
Infection (survival & growth of microorganism)
Damage to body
Chain of Infection
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HAREM entry
Steps in development of
Infectious Disease:
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1) Source of microbe: major source of disease
agents in the dental office are the mouths of
the dental patients.
Since we can’t tell who may harbor these
pathogens,
All patients must be treated the same
As if they are contagious/infectious
Steps in development of
Infectious Disease:
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2) Escape of the microbe from the source
During a variety of natural mechanisms such
as coughing, sneezing, talking
Anything removed from patient’s mouth can
carry microbes (instruments, film holders, etc)
Air/water spray can aerosolize microbes—
microbes can attach to water in spatter
Steps in development of
Infectious Disease:
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3) Spread of the microbe to another person
Transmission can be:
– DIRECT CONTACT
– INDIRECT CONTACT
– AEROSOL/DROPLET
Steps in development of
Infectious Disease:
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4) Entry of the microbe into new person: the
microbes are introduced into a new host
5) Infection (survival and growth of microbe) –
the multiplication and survival of
microorganisms on or in the body
6) Damage to the body – infecting
microorganism usually must multiply to a
harmful level for disease to occur
Universal Precautions
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ALL PATIENTS SHOULD BE TREATED AS IF
THEY HAVE A COMMUNICABLE DISEASE
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OR AS IF THEY ARE INFECTIOUS
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WHY?
Universal Precautions:
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Why?
We can’t tell by looking at a person if they are
carrying an infectious microorganism.
We must treat everyone the same.
Some patients may not know they are carrying
infectious microorganisms.
Some patients may not tell us.
CDC on Standard Precautions
CDC
Disease Transmission
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ASYMPTOMATIC CARRIER
Asymptomatic – having no symptoms of
disease (or at least none that are obvious)
Carrier – a person who may harbor pathogenic
agents and not get the disease but who may
pass it on to others
Disease Transmission
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Asymptomatic carrier
Could be someone who has had a disease and
recovered from it and may be a potential
carrier of the pathogenic microorganism.
Carrier transmitted: Tuberculosis,
Hepatitis B, Human immunodeficiency virus
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Stages of an infectious disease:
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Incubation stage
Prodromal stage
Acute stage
Convalescent stage
Stages of infectious disease:
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Incubation stage – period from the initial
entrance of the infectious disease agent into
the body until the first signs and symptoms of
the disease appear.
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Can range from a few hours to years,
depending on the potential of the microbe
Stages of infectious diseases:
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Incubation: the entering microorganism must
multiply to sufficient numbers to cause
symptoms (e.g., fever, swelling, skin
discoloration, ulceration, pain, bleeding, watery
eyes, “running nose”, etc)
Influenza & Respiratory – 2-3 days
Others can be weeks or even years
Stages of infectious diseases:
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Prodromal stage: appearance of early
symptoms
Means “running before”
First symptoms commonly called Malaise (not
feeling well)
Can be a slight fever and headache
Can be an upset stomach
Stages of infectious diseases:
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Acute stage: Symptoms of disease are
maximal.
PERSON IS OBVIOUSLY ILL.
Usually these patients are not likely to come to
the dental office except in an emergency
It would be better for these patients to delay
dental treatment.
Stages of infectious diseases:
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Convalescent stage: Recovery phase
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Numbers of microorganisms may be declining
but infectious agents (pathogens) are present
and may be spread during this stage
Modes of Disease Transmission
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Direct contact – contact with microbe at the
source such as in the patient’s mouth
Indirect contact – contact with items
contaminated with patient’s microorganisms
such as instruments, film holders
Droplet/Aerosol /Airborn– contact with sprays,
splashes, aerosols, or spatter containing
microorganisms
Routes of Entry:
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Inhalation
Ingestion
Mucous Membrane
Breaks in skin
Pathogenic Properties of Microbes
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Enhance Infection
Interfere with host defenses
Damage cell or tissue
Host Defense mechanisms
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Physical Barriers
Mechanical Barriers
Antimicrobial barriers
Cellular barriers
Immunity
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The state of being resistant to the harmful
effects of a microbe. Activated by ANTIGENS.
Body produces antibodies
Natural or Acquired ( Artificial)
active or passive
Active
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Survive disease (natural)
Immunize (acquired)
Passive
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These are LONG TERM
Breastfeed
Take antibiotics
Terms
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Allergen
Histamine
Antihistamine
Antigen
Urticaria
anaphylaxis