Lecture 3-6 - Descriptive Epidemiology & Measures of Disease Frequency

Question 1

What are the different types of surveillance systems?

Answer 1

• passive surveillance
• active surveillance
• syndromic surveillance

Question 2

What is the passive surveillance system?

Answer 2

Regulations requiring the healthcare system to report certain diseases/conditions.

Question 3

What is the active surveillance system?

Answer 3

When public health officials go into communities to search for new cases of disease.

Question 4

What is the syndromic surveillance system?

Answer 4

Looks at pre-defined signs and symptoms which are related to rare but traceable diseases.

Question 5

What is the induction/incubation period of a disease?

Answer 5

The time between exposure and onset of symptoms; subclinical stage

Question 6

What is the latency period of a disease?

Answer 6

The time between onset of symptoms and diagnosis.

Question 7

What is a case definition?

Answer 7

A set of uniform criteria that are used to define a disease/condition so there may be consistency in reporting.

Question 8

What are the categories of case definitions?

Answer 8

• confirmed

- probable

Question 9

Define epidemic.

Answer 9

Increased occurrence of disease form normal.

Question 10

Define outbreak.

Answer 10

Increase occurrence of disease from normal localized to a specific area.

Question 11

Define endemic.

Answer 11

The normal prevalence of a disease in a certain area exceeds what is normal for other areas.

Question 12

Define emergency of international concern.

Answer 12

An epidemic that requires the global community to be on alert; pre-pandemic.

Question 13

Define pandemic.

Answer 13

An epidemic on a global scale

Question 14

What is the Epi curve?

Answer 14

A graphical depiction of number of cases by date in an area during an outbreak or epidemic.

Question 15

What is a proportion?

Answer 15

Division of two related numbers; part-over-whole

Question 16

What is a ratio?

Answer 16

Division of two unrelated numbers; numerator is not part of the denominator.

Question 17

What is a rate?

Answer 17

A proportion with time in the denominator.

Question 18

What factors must be taken into account when comparing measures of disease frequency between different groups?

Answer 18

• number of people affected
• the size of the source population
• duration the population was followed

Question 19

What must be done when comparing measures of disease frequency between groups if the population size or duration the population was followed are not the same?

Answer 19

You must standardize

Question 20

What is incidence and how do you calculate it?

Answer 20

The number of new cases of disease.

-# of new cases of disease / total population at risk

Question 21

What is prevalence and how do you calculate it?

Answer 21

Total case of disease, both existing cases and new cases.

-(# of existing cases + # of new cases) / total population at risk

Question 22

What is crude morbidity rate?

Answer 22

The percentage of people in the population that have any disease over a period of time.

-# of people with disease / total population

Question 23

What is crude mortality rate?

Answer 23

The percentage the population that dies within a period of time.

of deaths / total population

Question 24

What is cause-specific morbidity rate?

Answer 24

The percentage of people with a specific disease in a population over a period of time.

-# of people with specific disease / total population

Question 25

What is cause-specific mortality rate?

Answer 25

The percentage of people who die from a certain disease in the population over a period of time.

-# of deaths due to a specific disease / total population

Question 26

What is case-fatality rate?

Answer 26

Percentage of people with a specific disease that die from their disease.

-# of deaths due to a specific disease / the number of people with the disease

Question 27

What is cause-specific survival rate?

Answer 27

The percentage of people with a certain disease still alive over a period of time.

-# of people alive with a specific disease / total of people who have the disease

Question 28

What is proportional mortality rate?

Answer 28

The percentage of deaths due to a certain disease over a period of time.

-# of deaths due to a specific disease / # of deaths

Question 29

What is live birth rate?

Answer 29

of live births / 1,000 population

Question 30

What is fertility rate?

Answer 30

of live births / 1,000 women of child bearing age (15-44)

Question 31

What is neonatal mortality rate?

Answer 31

of deaths <28 days of age / 1,000 live births

Question 32

What is postnatal mortality rate?

Answer 32

of deaths >28 days of age but <1 year of age / 1,000 live births

Question 33

What is infant mortality rate?

Answer 33

of deaths <1 of age / 1,000 live births

Question 34

What is maternal mortality ratio?

Answer 34

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

Question 35

What is infectivity?

Answer 35

The ability of an infectious disease to infect a patient.

-# infected / # at risk

Question 36

What is pathogenicity?

Answer 36

The ability of an infectious disease to cause clinical disease.

-# with clinical disease / # infected

Question 37

What is virulence?

Answer 37

The ability of an infection disease to be lethal.

• # of deaths / # with clinical disease
• case-fatality rate