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EPIDEMIOLOGY AND NOSOCOMIAL INFECTIONS
CHAPTER 15
What is Epidemiology?
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Table 33-1
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Epidemiology
What is Epidemiology?
Etiology
Incidence
Prevalence
causation
a/a+b
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Epidemiological Terms
Morbidity
Mortality
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Figure 33-6
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Diseases in Populations
Endemic
Epidemic
Pandemic
Sporadic
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Figure 33-2
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Incidence Types
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Disease Spread
Common Source Outbreak
Propagated Epidemic
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Epidemiologic Studies Descriptive
Analytical
Experimental
The Basic Triad Of Descriptive Epidemiology
THE THREE ESSENTIAL CHARACTERISTICS OF DISEASE WE LOOK FOR IN DESCRIPTIVE EPIDEMIOLOGY:
TIME PLACE PERSON
Time Changing or stable?
Seasonal variation.
Clustered (epidemic) or evenly distributed (endemic)?
Point source or propagated.
Place Geographically restricted or
widespread (pandemic)?
Relation to water or food supply.
Multiple clusters or one?
Person Age
Socio-economic status
Gender
Ethnicity/Race
Behavior
The Basic Triad Of Analytic Epidemiology
THE THREE PHENOMENA ASSESSED IN ANALYTIC EPIDEMIOLOGY ARE:
HOST
ENVIRONMENTAGENT
Agents
Nutrients Poisons Allergens Radiation Physical trauma Microbes Psychological experiences
Host Factors
Genetic endowment
Immunologic state
Age
Personal behavior
Environment Crowding Atmosphere Modes of communication – phenomena in
the environment that bring host and agent together, such as:– Vector– Vehicle– Reservoir
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Infection Reservoirs
Human
Animal
Non-living
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Microbe Spread
Portals of Entry
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Microbe Spread
Portals of Exit
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Modes of Disease Transmission Contact
Vehicles
Vectors
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Problems in Disease Transmission
Disease Cycles Herd Immunity
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Controlling Disease Transmission
Biosafety
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Public Health Organizations
Center for Disease Control (CDC)
World Health Organization (WHO)
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Notifiable Diseases
Definition:
Nationally Notifiable Infectious Diseases
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Nosocomial Infections
Sources
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Nosocomial Infection Risks Susceptibility Transmission Universal Precautions
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Figure 33-9
Other17%
Blood-streaminfections14%
Urinarytractinfections32%Pneumonia
15%
Surgicalsite infections22%
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Risks Equipment/Procedures Sites of Infection
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Bioterrorism
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Anthrax
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Smallpox