Lec 2-4. Descriptive Epi & measures of disease frequency

Question 1

Define case definitions

Answer 1

a set of uniform criteria used to define a disease/condition for public health surveillance

Question 2

What is the most critical element that must be defined before any of the ‘Who’ of descriptive epi can be acquired?

Answer 2

Case definition.

Question 3

What does a cluster mean?

Answer 3

Occurrence of disease in a very small population. Smaller than outbreak.

Question 4

Define Endemic

Answer 4

location that already has a higher than normal frequency of disease but that is their baseline.

Question 5

Define epidemic

Answer 5

Occurrence of disease clearly in excess of normal. Population is bigger than outbreak.

Question 6

What is the NNDSS?

Answer 6

CDC’s National Notifiable Diseases Surveillance System

Question 7

What is the Incubation period?

Answer 7

Time between exposure & onset of disease. Basically pt exposed and disease process starts. Doesn’t know if pt feels it or not.

Question 8

What is the Induction period?

Answer 8

Time between exposure & onset of disease. Basically pt exposed and disease process starts. Doesn’t know if pt feels it or not.

Question 9

What is the Latency period?

Answer 9

Time between onset & disease detection. Basically how long does it take for someone to find it out.

Question 10

Define Outbreak

Answer 10

Epidemic limited to a localized increase in occurrence of disease. Bigger than cluster, smaller than epidemic.

Question 11

Define Pandemic

Answer 11

Epidemic spread world-wide.

Question 12

Define epidemic curve

Answer 12

Graphical representation incorporating all 3 elements of descriptive epi. Person place time.

Question 13

What things do epidemic curves visually demonstrate?

Answer 13

Magnitude & timing, and pattern of disease occurrence.

Question 14

what does Magnitude and timing of disease occurrence mean pertaining to an epi curve?

Answer 14

Magnitude: numerical, we can see numbers. The bar gets taller more cases are being counted. Time: hours, days, months on the speed or aggressiveness of an illness.

Question 15

Define a sentinel or index case

Answer 15

The first case.

Question 16

What are two sub categories of Pattern of disease pertaining to an epi curve.

Answer 16

Common/point source (continuous & intermittent) and propagated source.

Question 17

Define common/ point source (continuous & intermittent)

Answer 17

Not person-to-person spread, by a point source.

Question 18

Define propagated source

Answer 18

person-to-person spread

Question 19

What three hypotheses can the epi curve form?

Answer 19

Routes of transmission, probable exposure period, and incubation period.

Question 20

Why can a disease be categorized as intermittent?

Answer 20

Disease is short lived

Question 21

What are the 3 basic types of relative measures of disease frequencies?

Answer 21

Proportions, ratios and rates

Question 22

Define proportions

Answer 22

Simple percentage, part over whole. Division of 2 RELATED numbers. Numerator is a subset of the denominator.

Question 23

Define ratios

Answer 23

Division of 2 unrelated numbers. Numerator is not part of the denominator.

Question 24

Define rates

Answer 24

A proportion (%) with TIME incorporated into the denominator.

Question 25

What are 3 key factors in comparing measures of Disease frequency BETWEEN groups

Answer 25

How many people affected, size of the source population population, and the length of time following that population for that disease to occur.

Question 26

What do you do when the size of the source population and length of time the population is followed are not the same between populations?

Answer 26

Standardize

Question 27

What two terms describe disease frequency?

Answer 27

Incidence and prevalence

Question 28

Define incidence

Answer 28

New cases of disease.

Question 29

Prevalence

Answer 29

Existing cases of disease + New cases of disease.

Question 30

True or False? Prevalence and incidence are both proportions.

Answer 30

True

Question 31

Answer 31

Continuing source outbreak

Question 32

Answer 32

Common/point source no propogation, no sentinal case.

Question 33

Answer 33

Common/point source with index case and limited spread

Question 34

Answer 34

Common/point source. intermittent outbreak

Question 35

Answer 35

Propagated with index case

Question 36

What are the 5 core functions of the discipline of Epidemiology?

Answer 36

Identify patterns/trends, determine extent, study natural course, identify the causes of or risk factors of health related events, evaluating effectiveness of measures

Question 37

What is the formula for Incidence?

Answer 37

of NEW cases of illness/ # of ppl at RISK of illness

Question 38

What is cumulative incidence?

Answer 38

Summed over multiple time periods. As Incidence goes UP then the denominator goes DOWN

Question 39

What are key words for Incidence questions?

Answer 39

Attack rate or Risk

Question 40

What is the equation for Incidence Rate?

Answer 40

of NEW cases of disease/ Person-TIME at risk for disease

Question 41

What is a fixed population?

Answer 41

Stable not changing population

Question 42

What is a dynamic population?

Answer 42

Constantly changing population

Question 43

What is the equation for prevalence?

Answer 43

of existing cases of disease/ # of ppl in population

Question 44

What is point prevalence?

Answer 44

Prevalence at a given time. Example: specific day

Question 45

What is period prevalence?

Answer 45

Prevalence over a given period time. Example: year, month

Question 46

What is the eq for Case-Fatality rate?

Answer 46

of cause-specific deaths/ # of cases of disease

Question 47

What is the eq for cause-specific survival rate?

Answer 47

of cause specific cases alive/ # of cases of disease

Question 48

What is the eq for proportional Mortality Rate?

Answer 48

of cause specific deaths/ total # of deaths in population

Question 49

What is the eq for Live birth rate?

Answer 49

of live births/ 1,000 population

Question 50

What is the eq for Fertility Rate?

Answer 50

of live births/ 1,000 women of child bearing age

Question 51

What is the eq for Neonatal Mortality Rate?

Answer 51

of deaths in those \<28 days old/1,000 live births

Question 52

What is the eq for Postnatal Mortality Rate?

Answer 52

of deaths in those greater than or equal of 28 days but younger than 1 yr/ 1,000 live births

Question 53

What is the eq for Infant Mortality Rate?

Answer 53

of deaths in those less than 1 yr old/ 1,000 live births

Question 54

What is the eq for Maternal Mortality Ratio?

Answer 54

of female deaths related to pregnancy/ 100,000 live births

Question 55

What is the eq for infectivity?

Answer 55

infected/ # at risk

Question 56

What is the eq for Pathogenicity?

Answer 56

with clinical disease/ # infected

Question 57

What is the eq for Virulence?

Answer 57

of deaths/ with infectious disease

Question 58

Define Morbidity

Answer 58

how many sick

Question 59

Define Mortality

Answer 59

how many died

Question 60

What is the eq for crude morbidity rate?

Answer 60

of ppl with disease/ # of persons in population

Question 61

What is the eq for crude mortality rate?

Answer 61

of all deaths/ # of persons in population

Question 62

What is the eq for cause-specific morbidity rate?

Answer 62

of people with cause specific disease/ # of persons in population

Question 63

What is the eq for cause-specific mortality rate?

Answer 63

of case specific deaths/ # of person in population

Question 64

What does CDC stand for?

Answer 64

Center for Disease Control

Question 65

What does MMWR stand for?

Answer 65

Morbidity and Mortality Weekly Report

Question 66

What does WHO stand for?

Answer 66

World Health Organization

Question 67

What is the eq for survival rate?

Answer 67

those who survived/ all affected

Question 68

What is secondary attack rate?

Answer 68

measure of frequency of new cases of disease among the contacts of known cases