CIC Epidemiology

Question 1

Epidemiological triangle

Answer 1

host
                            / \
                          /     \
                        /         \
                      /             \
           agent -----------environment

Question 2

Resevoir

Answer 2

-place where infectious agent can survive, but might not multiply

Question 3

Herd Immunity

Answer 3

-high proportion of group resistant to infectious agent

Question 4

Qualitative research

Answer 4

• understanding human experience

- interpretative approach to subject and context

Question 5

Fomite

Answer 5

inanimate object where organisms can reside; transmission risk

Question 6

Quantitative research

Answer 6

-causative relationship suggested by numerical data, at least two variables

Question 7

Cross-sectional study

Answer 7

• prevalence, correlation or survey study
• population’s risk factors and outcomes reviewed at given point of time
• incidence rates cannot be determined

Question 8

Case-control study

Answer 8

• population with and without chosen outcome studied for exposure to one or more risk factors
• quick, inexpensive

Question 9

Clinical Trial

Answer 9

-interventions randomly assigned to participants
usually double blinded (participants and investigator not aware of who is assigned to intervention or control group)
-considered gold standard for casual relationship
-expensive, time consuming
-random assignment results in variable participant characteristics

Question 10

Attack rate

Answer 10

• (number of new cases with disease or condition/population at risk) x 100
• expressed as a percentage, e.g., 5% of population, or cases per 100 population

Question 11

Cohort study

Answer 11

-prospective or longitudinal study
population sample with and without exposure to select risk factors studies for outcomes incidence
-stronger casual relationship

Question 12

Incidence rate

Answer 12

-(number of new cases/population at risk) x constant

constant = multiples of 10 to achieve whole number

Question 13

Incidence density

Answer 13

-(number of new cases/exposure time, e.g., device days) x constant

Question 14

Prevalence rate

Answer 14

-(number of existing cases at given moment in time/population at risk at same moment in time) x 100

Question 15

Sensitivity

Answer 15

-percentage of persons with true POSITIVE results when persons WITH disease tested

Question 16

specificity

Answer 16

-percentage of persons with true NEGATIVE results when persons WITHOUT disease tested

Question 17

Nominal scale

Answer 17

• words used to describe groups or categories
• one category is not considered to be higher or lower than another
  e. g., nurses, physicians, EVS, etc

Question 18

Mortality rate

Answer 18

-(number of deaths/population at risk) x 100

Question 19

Outbreak Investigation

Answer 19

1. suspect
2. outbreak exists
3. collaborate with key persons
   a. case definition
   b. investigation period
   c. case finding methods
4. formulate hypothesis
5. implement and evaluate
6. prepare and send reports

Question 20

Ordinal scale

Answer 20

-numbers used to rank classifications
-relationship between classifications
e.g., likert scale
first, second, third
cancer staging, etc

Question 21

Range

Answer 21

• difference between largest and smallest number in data set
  e. g., data set: 2,3,7,8,21
  range: 21-2=19

Question 22

“Out of Control” data

Answer 22

• data point above UCL or below LCL
• nine consecutive points on one side of mean
• six consecutive points increasing or decreasing
• 14 consecutive points alternating up and down
• 15 consecutive points 1 SD above or below mean
• 2 of 3 consecutive points within 2 to 3 SD
• 4 of 5 consecutive points within 1 to 2 SD

Question 23

Interval scale

Answer 23

-original data with difference between any two observations
e.g., 1-3, 4-6, 7-9
age, BP, weight, temperature, etc.

Question 24

Deviation

Answer 24

-actual difference between data point and mean

Question 25

Prospective study

Answer 25

• usually require long follow up period

- looks forward

Question 26

Chi square test

Answer 26

• evaluated effect of variable on outcomes
• calculates odds ratio or relative risk
• data in each cell needs to be greater than 5

Question 27

Surveillance

Answer 27

• includes data collection, data analysis & correlation

- does not include causation

Question 28

Mean
Mode
Median

Answer 28

• average
• most frequent number in data set
• middle

Question 29

Epidemiology

Answer 29

• study of distribution & determinants of disease
• studies frequency, types and factors that influence illness and injury in groups
• body of knowledge
• method of study

Question 30

Fisher’s Exact test

Answer 30

-used when numbers are small

Question 31

Normal distribution (graphed)

Answer 31

• continuous, symmetrical distribution, both tails extend to infinity
• shape of curve determined by mean and SD
• 95.5% data lies between mean & +/- 2 SD

Question 32

Casual association

Answer 32

• one factor increases probability of occurrence

- determined by strength of identification, consistency & biological plausibility

Question 33

Positive predictive value

Answer 33

-percentage of POSITIVE tests when disease PRESENT

Question 34

Epidemic curve

Answer 34

• Helps determine if source of infection common, and/or continuing
• identify probable exposure to source
• identify probable incubation period
• determine if problem is ongoing

Question 35

Standard deviation

Answer 35

-measure of dispersion that reflects data variability around mean

Question 36

Negative predictive value

Answer 36

-percentage of NEGATIVE tests when DISEASE IS NOT PRESENT