UNIT 2

Question 1

• branch of medical science that studies the distribution of disease in human population

Answer 1

EPIDEMIOLOGY

Question 2

It developed out of the search for causes of human disease in the 19th century

Answer 2

Epidemiology

Question 3

It is used to characterize the distribution of disease within a population. It describes the person, place, and time characteristics of disease occurrence.

Answer 3

Descriptive epidemiology

Question 4

It is used to test hypotheses to determine whether statistical associations exist between suspected causal factors and disease occurrence. It also is used to test the effectiveness and safety of therapeutic and medical interventions.

Answer 4

Analytical epidemiology

Question 5

These are used to explore associations of disease with variables of interest.

Answer 5

Cross-sectional studies

Question 6

It is defined as the usual occurrence of a disease within a population.

Small numbers of people affected example influenza

Answer 6

Endemic

Question 7

It is a sudden and great increase in the occurrence of a disease within a population. It may also be the first occurrence of an entirely new disease.

Answer 7

epidemic

Question 8

It is a rapidly emerging outbreak of a disease that affects populations across a wide geographical area. Pandemics often are worldwide in scope.

Answer 8

pandemic

Question 9

It refers to a disease that occurs infrequently and irregularly.

Answer 9

Sporadic

Question 10

It refers to persistent, high levels of disease occurrence.

Answer 10

Hyperendemic

Question 11

Epidemics can be classified according to their manner of spread through a population:

Answer 11

 Common-source
o Point
o Continuous
o Intermittent
 Propagated
 Mixed
 Other

Question 12

It is one in which a group of persons are all exposed to an infectious agent or a toxin from the same source.

Answer 12

common-source outbreak

Question 13

If the group is exposed over a relatively brief period, so that everyone who becomes ill does so within one incubation period, then the common-source outbreak is further classified as a:

Answer 13

point-source outbreak.

Question 14

In some common-source outbreaks, case-patients may have been exposed over a period of days, weeks, or longer.

In a continuous common-source outbreak. The epidemic curve of anintermittent common-source outbreakoften has a pattern reflecting the intermittent nature of the exposure.

Question 15

It results from transmission from one person to another. Usually, transmission is by direct person-to-person contact, as with syphilis.

Answer 15

propagated outbreak

Question 16

Some epidemics have features of both common-source epidemics and propagated epidemics. The pattern of a common-source outbreak followed by secondary person-to- person spread is not uncommon.

Answer 16

Mixed Epidemics

Question 17

Finally, some epidemics are neither common-source in its usual sense nor propagated from person to person.

Outbreaks of zoonotic or vectorborne disease may result from sufficient prevalence of infection in host species, sufficient presence of vectors, and sufficient human-vector interaction

Question 18

use the total number of disease cases and the entire population in their calculations

Answer 18

Crude rates

Question 19

differentiate cases and populations by cause, age, sex, race, or other factors

Answer 19

Specific rates

Question 20

allow for the comparison of populations with different characteristics.

Answer 20

Adjusted rates

Question 21

It represents the illness, symptoms, or impairments produced by a disease,

Answer 21

Morbidity

Question 22

It is death caused by a disease.

Answer 22

Mortality

Question 23

Acute diseases are those that strike and disappear quickly, within a month or so (e.g., chickenpox and influenza).

Chronic diseases are those that are long-term; chronic diseases often are incurable (e.g., many forms of cancer and diabetes mellitus).

Question 24

It is a special type of proportion that includes a specification of time, and the numerator of the proportion is included in the denominator.

Answer 24

Rate

Question 25

Rates can be expressed in any form that is convenient (e.g., per 1,000, per 10,000, or per 100,000). Infant mortality rates, for example, are typically expressed per 1,000 live births, whereas cancer rates are expressed per 100,000 population.

Question 26

It measures the occurrence of new cases of a disease in a population over a period of time. It is an important measure for evaluating disease-control programs and has implications for the future problems of medical care.

Answer 26

incidence rate

Question 27

It measures the total number of existing cases of a disease in a population at a given point in time or over a period of time. It is a useful indicator of the burden of a disease on the medical and social systems of a geographic region.

Answer 27

prevalence rate

Question 28

It measures the proportion of individuals in a defined population that have a disease or other health outcomes of interest at a specified point in time (point prevalence) or during a specified period of time (period prevalence).

Answer 28

Prevalence

Question 29

It is a measure of the number of new cases of a disease (or other health outcome of interest) that develops in a population at risk during a specified time period.

Answer 29

incidence

Question 30

Is related to the population at risk at the beginning of the study period

Answer 30

Risk (or cumulative incidence)

Question 31

Is related to a more precise measure of the population at risk during the study period and is measured in person-time units.

Answer 31

Rate

Question 32

It assumes that the entire population at risk at the beginning of the study period has been followed for the specified time period for the development of the outcome under investigation. However, in a cohort study participants may be lost during follow-up.

Answer 32

incidence risk

Question 33

Incidence rates also measure the frequency of new cases of disease in a population. However, incidence rates take into account the sum of the time that each person remained under observation and at risk of developing the outcome under investigation.

Question 34

It is a measure of the frequency of occurrence of death in a defined population during a specified interval.

Answer 34

Mortality Rate

Question 35

It is the number of resident live births for a specified geographic area (nation, state, county, etc.) during a specified period (usually a calendar year) divided by the total population (usually mid-year) for that area and multiplied by 1,000.

Answer 35

Crude Birth Rate

Question 36

It is the number of resident live births for a specified geographic area (nation )

Answer 36

Fertility Rate

Question 37

It is the probability of a child born in a specific year or period dying before reaching the age of one, if subject to age-specific mortality rates of that period.

Answer 37

Infant Mortality Rate

Question 38

Infant Mortality Rate is strictly speaking not a rate (i.e. the number of deaths divided by the number of population at risk during a certain period of time) but a probability of death derived from a life table and expressed as rate per 1000 live births.