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Flashcards in Reporting Disease Occurence Deck (40)
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1

What 3 things make up the Epidemiologic Triangle?

 

  • Host
  • Environment
  • Agent

2

What does the Epidemiologic Triangle represent?

  • Traditional model of causation for dz.
  • whether or not a dz will occur in an individual

3

What 3 things determine the level of DZ in a population?

  • Individual factors
  • Spatial factors
  • Temporal factors

(who, when, where!)

4

 

How may we report the occurence of a DZ & it's frequency? (4)

  • Onset in time
  • By time series analysis
  • Host related factors
  • Geographical location
  • Combo of above

5

Temporal Dimensions of Dz focus on what?

Whether or not a DZ is endemic, sporadic, epidemic or pandemic

6

How does an Endemic DZ occur?

(3)

  • occurs at expected frequency
  • present at all times
  • usually low & predictable levels

7

How does an Epidemic Dz occur?

(2)

  • occurs at greater than expected frequency
  • can be depicted graphically as epidemic curves

8

When does a Sporadic DZ occur?

(3)

  • single case or small cluster of cases
  • infrequently
  • irregular & unpredicatable

9

List the 3 basic Epidemic Curves.

  • Point Source Epidemic
  • Continous, Common Source Epidemic
  • Propagating Epidemic

10

What type of Epidemic Curve is this?

Point Source

11

List the characteristics of a

Point Source Epidemic Curve

  • Population is subjected to the same BRIEF exposure over a defined period of time (usually 1 intubation period)
  • Shape: rises rapidly, definite peak, followed by a decline
  • No new cases occur once the point source is removed

12

What type of Epidemic curve is this?

 

Continous, Common Source Epidemic

13

List the characteristics of a

Continous, Common Source Epidemic.

  • Prolonged exposure to the source over an extended period of time ( >1 intubation time)
  • Sharp down slope= common source removed
  • Gradual down slope= outbreak exhausts itself

14

What type of Epidemic curve is this?

 

Propagating Epidemic

15

______ epidemic occurs when a DZ is introduced through a single source and subsequently transmitted to others (2O cases)

Propagating Epidemic

16

What form of analysis uses information of patterns of DZ occurence obtained form temporal occurence?

Time Series Analysis

17

Purpose of Time Series Anaylsis?

ID persons of high or low risk so causal assocations can be explored

18

3 trends that influence patterns of DZ occurence?

  • Short-term
  • Cyclical (+ seasonal)
  • Secular (long term)

19

Trend Characteristics:

  • Rise & fall of a DZ over > 1 yr.
  • Regular, periodic fluctations in level of DZ occurence

Cyclical trends

20

Trend Characteristics:

  • Special case of cyclical trend
  • periodic fluctuations in DZ incidence related to particular seasons

 

Seasonal Trends

21

4 things that cause fluctuations in

Seasonal Trends?

  • host density
  • management practices
  • vectors
  • infectious agent survival

22

Overall rise or decline in incidence occuring gradually over long periods of time

Secular Trend

23

  • Describes the proportion of a population, initially free of the DZ of interest, that develops the DZ over a given period of time.
  • Refers to NEW cases of dz.

 

Incidence

24

How do you calculate Incidence?

Per # of individuals

(unit of population expressed as whole #s & in smallest multiples of 10)

 

25

  • Proportion of the population at a given time that have the factor of interest.
  • Expressed either as a proportion btwn 0-1, as a %, or as a # per unit of population at risk

Prevalence

26

How do you calculate Prevalence?

27

Which measure takes into account the duration of disease?

Incidence

28

An important measure of the burden of DZ in the population & is useful in developing health policies

Prevalence

29

What is the relationship between

Incidence & Prevalence?

Prevalence (P) = Incidence (I) x Duration of DZ (D)

P = I x D

30

What can cause a change in Prevalence?

(3)

Changes in:

  • Incidence
  • Avg. Duration of DZ
  • Both Indicence & Duration of DZ