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Epidemiology Quiz 1 2017

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moonlup's version from 2017-01-26 03:54

Section 1

Question Answer
CDCCenters for Disease Control and Prevention
OIEWorld Organization for Animal Health
USDAUS Department of Agriculture
APHISAnimal and Plant Health Inspection Service
FSISFood Safety and Inspection Service
AVMAAmerican Veterinary Medical Association
Epidemiologystudy of what is upon the population
Populationtotality of individuals that share common attributes
EBMEvidence Based Medicine: use of current best evidence in making care decisions
Epidemiologic ProcessID risk factors, Determine frequency in population, Strategic planning
Endemic/EnzooticUsual, constant frequency of disease in a population
Epidemic/EpizooticDisease that rapidly spreads to many individuals over a short period; outbreak
Pandemic/Panzooticwidespread epidemic involving more than one country
WHO PandemicNew disease caused by infections that spreads easily and causes high morbidity and mortality
SporadicNot new disease that occurs infrequently in a population, not rapidly spread
SurveillanceOngoing, Systemic collection, analysis, interpretation, and dissemination of data re: health events
Hostindividual that harbors or is exposed to an infectious agent
Demographicpersonal characteristics of an individual or group
Case (a case of)Diseased individuals that meet selected criteria stated by the case definition
Causal factor/Determinant/Risk factor/Exposure Factorfactor that directly influences occurrence of disease
Infectionencounter of potentially pathogenic agent with susceptible host that shows immunologic response
Diseaseclinically apparent infection
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Section 2

Question Answer
Epidemiologic TriangleWho (Host), What (Agent), Where (Environment). Determines if Disease occurs.
How can disease occurrence be reported?Time, Host Distribution, or Space
What's an epidemic curve?histogram of new cases over time
What are the types of epidemic curve?Point, Continuous, or Propagating
What is a Point Source Epidemic Curve?Large number of cases in population exposed in a SHORT time period, contains a definite peak
What is a Continuous Epidemic?Source exposure is prolonged and may occur over more than one incubation period, down slope may be sharp or gradual
What is Propagating Epidemic?Disease introduced by single infected animal and then transmitted, curve has secondary points
What are the types of Time Series Analysis?Short term, Cyclical/Seasonal, Secular (Long term)
IncidenceFrequency of new cases of disease in a population over a set period of time
PrevalenceNumber of cases in a given population
Attack rateProportion of population that develop disease after exposure in an outbreak
Incidence formulaNew cases/individuals exposed x 1000* *whatever gives you a whole number
Prevalence formulaDiseased individuals/individuals exposed (can be single point or over time)
How are incidence and prevalence related?Prevalence = Incidence x Disease Duration
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Section 3

Question Answer
Causeevent, condition, or characteristic that without the disease would not occur
Types of Causal FactorsAgent factors, Environmental influences, Host factors
Agent FactorsInfection, Pathogenicity, Virulence
Infectionability to establish itself in host
Pathogenicability to produce disease
Virulenceseverity of disease
Cause and strength of associationassociation is not causation, Non-statistical, Statistical, Risk Factors. Use confidence intervals.
Types of risk factorsgenetic, behavioral, environmental
Cause and temporal precedenceevidence reflects that cause preceded disease
Dose-response relationship and causecertain level required to cause disease
Biological plausibility and causecause makes biological sense
Consistency and causerelationship IDed by multiple researchers
Elimination and causelab test to differentiate causes
Reversible association and causefactor removal results in decreased frequency of disease
Strength of study designs and causesome studies provide better evidence than others
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Section 4

Question Answer
Biassystematic error that results in incorrect estimate of the association between exposure and disease risk
Types of biasselection and information
Selection biasdistortion in way subjects are selected for study
Types of selection biassurveillance, non-response, inappropriate comparison group
Types of information biasInterviewer, Recall, Inaccurate/Incomplete Data, Misclassification, Observer
Types of random samplingSimple, systematic, stratified, cluster
Simple random samplingeach subject has an equal chance of being selected
Systematic random samplingsampling has a known and equal predefined interval (every 4th animal)
Stratified random samplingsamples are divided into strata and random samples are taken from each strata
Cluster samplingselection of samples in space and time
Types of Non-random samplingConvenience, Purposive, Haphazard
When is non-random sampling used?clinical research, but has biased population estimates
Convenience samplingthe most accessible samples are collected
Purposive samplingmost desired samples are selected
Haphazard samplingsamples selected without any method in mind
Confoundingdistortion or masking of an association between exposure and disease by a third factor (age, sex, etc)
How can you control confounding?randomisation, matching, restriction, stratification, multivariate
Matching for confoundingonly works for known confounders and can no longer assess what you matched (age, sex, etc)
Restriction for confoundinglimit the study to a subgroup homogenous for the confounder (risks bias)
Stratification for confoundingevaluate association within subgroups of the confounder (works best if only one)
Multivariate for confoundingtakes into account many variables that may confound
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Section 5

Question Answer
Descriptive studiesearliest studies done to observe occurrence and distribution, where, who, when. Used to generate hypotheses
Analytical studiesused to ID and explain causes of disease, attempts to quatify risk factors
Case Reportcan lead to new hypothesis as often describes new disease
Case SeriesMinimum of 5 cases with common features
Cross-sectional studiesaka Prevalence study, snapshot of health at a point in time (opinion polls)
What's a 2x2 table for?measure association between exposure factor and occurrence or absence of disease
Independent variablescharacteristic being observed or measured that is hypothesized to affect the occurrence of disease
Dependent variablesdisease manifestation whose variation we seek to explain by the influence of independent variables
Ecologic studiesaka Aggregate level study, data used on populations instead of individuals, ideal for finding geographical correlations. Can't be used to determine cause of disease.
Ecological Fallacyassumption that association found at population level is true on the individual level
memorize