Epi, Surveillance, and Outbreaks Flashcards
study of the frequency, distribution, cause, and control of disease in populations- forms the basis of all health-related studies. Provides the background for interventions to reduce transmission of infecting organisms, reduce the number of healthcare ass infections, and protect hc providers from infection
epidemiology
Main components of epi definition
frequency
distribution
cause
control
Ds of epi
Distribution
Determinants
Deterrents
How we describe determinants
Person
Place
Time
epi triangle
Host
Agent
Env
As one variable changes, there is a concomitant or resultant change in the quantity or quality of another variable
Association
3 types of associations
- artifactual (spurious)
- Indirect or noncausal
- causal
This type of association may be caused by errors in study design or analysis, bias, errors in analysis, or failure to control for confounding variables
Artificial or spurious association
this type of association may be caused by mixing of effects between the exposure, disease, and confounding variable that may be associated with the exposure and independently affect the outcome of interest
Indirect or noncausal
This type of association occurs when evidence indicates that one factor is clearly shown to increase the probability of the occurrence of a disease
Causal
The stronger the relation between a risk factor and the effect, the less likely it is that the relation is due to a third or extraneous factor
Strength of assocition
Multiple studies in a range of settings report similar results
Consistency
Ideally, the effect has only one cause
Specificity
the purported cause should be present before the effect occurs
temporality
A dose-response relation between the risk factor and the effect
Biological gradient
there should be a rational the theoretical basis explaining how or why the risk factor led to the effect
Biological plausabiity
The association should not conflict with known facts
Coherence
Is there any supportive research based on experiment; if preventative action is taken, does the effect dissipate?
Experimental evidence
A previously accepted phenomenon in one area can be applied to another
Analogy
- strength of association
- consistency
- specificity
- temporality
- biological gradient
- biological plausibility
- coherence
- experimental evidence
- analogy
Bradford Hill’s Criteria for Causation
Level of prevention with the goal to complete prevention of diseases before any manifestation of that disease occurs
Primary
Early dx and treatment and preventing further deterioration by intervention as early in the disease course as possible
secondary
Reducing complications
Tertiary
Examples secondary prevention
Screening
skin testing for TB
Mammograms
Examples Primary prevention
Wellness programs
Immunizations
Folic Acid
Exercise
Seat Belts
Examples of tertiary prevention
Rehab
Organ transplantation
the number of existent cases of a given disease at a given time
prevalence
An excess over the expected incidence of disease within a given geographical area during a specified time period
Epidemic
An epidemic spread over a wide geographical area, across countries or continents
Pandemic
The usual incidence of a given disease within a geographical area during a specified time period
Endemic
Is a sudden increase in occurrences of a disease in a particular time and place
Outbreak
The number of new cases of a given disease in a given time periods
incidence
The probability or likelihood of an event occurring
RIsk
A place in which an infectious agent can survive but may or may not multiple
Reservoir
A characteristic, behavior, or experience that increases the probability of developing a negative health status
Risk factor
An inanimate object on which organisms may exist for some period of time
Fomite
The resistance of a group to invasion and to spread of an infectious gent, based on the immunity of a high proportion of individual members of the group
herd immunity
Infection that is not present at the time of admission to the hospital, but are temporally associated with the admission to or a procedure performed in a healthcare faciity
Healthcare associated infection
Infection present on admission with no association to a recent hospitalization
Community acquired infection
Reasons for OBs (often multifactorial)
- lapses in IP
- Colonization or infection for HCP
- Defects or contamination of product or device
When should outbreaks in healthcare be suspected?
HAIs or adverse events occur above the baseline rate or when an unusual microbe or adverse event is recognized
Can 1 case of an unusual disease be an outbreak?
Yes
Outbreak investigation: confirm
confirm presence of an outbreak
Outbreak investigation: alert
alert key partners about the investigation
Outbreak investigation: research
Perform a literature review
Outbreak investigation: define
Establish a preliminary case definition
Outbreak investigation: finding cases
Develop methodology for finding cases
Outbreak investigation: line list
Prep line list and epi curve
Outbreak investigation: observation
observe and review potentially implicated patient care activities
Outbreak investigation: sampling
consider whether env sampling should be performed
Outbreak investigation: control
implement control measures
Follow up investigation components
- refine the case def
- continue case finding and surveillance
- review regulatory control measures
- consider whether an analytic study should be performed
Organism response tier:
- contains resistance mechanisms novel to the U.S.
- Pan-resistant
- needs more extensive evaluation to better define risk for transmission
Tier 1
Example of Tier 1
Pan-R OXA-23 Acinetobacter baumanni
Organism response tier:
- primarily found if hc settings but not believe to be found regularly in the region
- information is available about how transmission occurs and groups primarily at risk
Tier 2
Examples of Tier 2
-Cabapenem resistant enterobacteriaceae with novel mechanisms
- VIM producing Pseudomonas aeruginosa
- NDM-producing CRE
- OXA-48 type producing CRE
Organism response tier:
- already established in U.S. and have been identified in the region before
- not endemic
- info is available about transmission
Tier 3
Example of tier 3
-carbapenem-resistant Enterobacteriaceae producing Klebsiella pneumoniae carbapenemase in regions where organism more commonly identified
What shows facilities with need for improvement?
TAP- targeted assessment prevention
What is CAD?
Cumulative attributable dif
(# of infections to prevent to meet goals)
Elements of a successful surveillance program : methods
Select methodology
