Epidemiology Midterm

Front 1

Host

Back 1

An organism that harbors a virus or parasite, typically providing nourishment & shelter.

Example: Cell (Virus), Animal (Parasitic Worm)

Hint 1

Anything Capable of harbouring/housing a diseases.

Front 2

Vector

Back 2

An organism that DOES NOT cause a disease itself, but spreads infection by conveying pathogens from one host to another

Example: Mosquito (Malaria), Flea (Bubonic Plague), Tick (Lyme Disease)

Hint 2

A living carrier that TRANSPORTS a disease

Front 3

Models of Disease Transmission: Direct

Back 3

Person to Person

Front 4

Models of Disease Transmission: Indirect

Back 4

(1) Common Vehicle: Single, Multiple, or Continuous exposure

(2) Vector

Front 5

Single-Exposure, Common Vehicle Outbreak

Back 5

1. Sudden, Rapid Increase in cases of Diseases

2. Few Secondary Cases

3. Log Transformation of a graph will show a bell shaped curve--Normal Distribution

Front 6

Carrier

Back 6

A person or animal that harbors a specific infectious agent in the absence of a discernable clinical disease and serves a potential source of infection.

This Induvidual MAY infect others!! (i.e--Typhoid Mary)

Front 7

Herd Immunity

Back 7

If a large percentage of the population is immune, the entire population is likely to be protected for some person-to-person communicable diseases.

Front 8

Endemic

Back 8

Habitual presence of a disease within a given geographic area

Front 9

Epidemic

Back 9

The occurance in a community or region of a group of illness of similar anture, CLEARLY IN EXCESS OF NORMAL EXPECTANCY, and derived from a common or from a propagated source

Front 10

Outbreaks

Back 10

Explosive. Sudden rapid increase in number of cases of disease.

Front 11

Pandemic

Back 11

A worldwide epidemic

Front 12

Incubation Period

Back 12

The interval between invasion by an infectious agent and apperance of the first sign or symptom of disease.

Front 13

Importance of the Incubation Period

Back 13

1. Infected persons could be able to transmit the diease (even if not showing any signs or symptoms)

2. Quarantine: Isolate induviduals to prevent spread/transmission

3. Determine the length of quarantine.

Front 14

Attack Rate

Back 14

# of People at risk (in whom a certain illness develops) / Total # of people at Risk

Front 15

Food-Specific Attack Rate

Back 15

# of people who ate a certain food and became ill / Total # of people who that that food

Front 16

Primary Case

Back 16

A person who acquires the disease from exposure (i.e- from contaminated food)

Front 17

Secondary Case

Back 17

A person who acquires the disease from a primary case

Front 18

Secondary Attack Rate

Back 18

The attack rate in susceptible people who have been exposed to a primary case

Front 19

Incidence Rate

Back 19

The number of NEW cases of a disease that occur in a population during a specified period of time in a population at risk for developing the disease

(Case Diagnosed previously are NOT included in the numerator or denominator)

Hint 19

# of New Cases of Disease / # of people at risk of developing the disease

Front 20

Cumulative Incidence

Back 20

The porportion of a group of people who experience the onset of a health related event during a specified time interval.

Hint 20

i.e- Age Specific & Cause Specific

"Have your Ever had asthma!?" (Birth to Date)

Front 21

Prevalence

Back 21

The number of events in a given population at a designated time;

Hint 21

# of Cases of a disease / # of persons in the population at risk

"WHO HAS IT RIGHT NOW"

Front 22

Point Prevalance

Back 22

The prevalence at the moment we measure it

Hint 22

i.e- "Do you have Asthma"

Front 23

Period Prevalance

Back 23

How many poeple have had the disease at any time during a certain period.

Hint 23

i.e- During a single calander year

i.e- "Have you had Asthma in the last year!?"

Front 24

Person-Year

Back 24

The unit combining time and population size. (If we compare 2 incidence rates in the same number of person-years, we would be able to compare how strong the force is that caused the disease)

Hint 24

Number of Persons x Observed Years

Front 25

Relationship between Incidence & Prevalence

Back 25

Prevalence = Incidence X Duration

Front 26

Determinants of Prevalence

Back 26

Incidence --->

Pool of Prevalence Cases-->

Death/Cure

Front 27

Passive Surveillance

Back 27

Denotes surveillance in which either available data on reportable diseases are used, or reporting is mandated or requested with the responsibility for the reporting often falling on the health care provider or health officer

Front 28

Active Surveillance

Back 28

Denotes a system in which project staff make periodic field visits to health care facilities to collect data; Most of which is through Surveys

Front 29

Surveillance

Back 29

A fundamental role of Public Health. It may be carried out through monitoring changes in disease frequency or to monitor changes in prevalence risk factors

Front 30

Case-Specific Mortality Rate

Back 30

# of Deaths from this cause in one year / # of persons at risk in the population in the midyear

Front 31

Cause-Fatality Rate (Percent)

Back 31

# of dying persons during a specific period of time after disease onsent or Diagnosis / # of induviduals with this disease

Front 32

Porportionate Mortality

Back 32

# of deaths from a diseae in a population during a period of time / Total number of deaths from all causes in this population

Front 33

YPLL (Years of Potential Life Loss)

Back 33

The statistical measure of premature death and years of potential life lost compared to a target age (65 or 70)

Hint 33

Find the Average Age group & Subtract it from 65. Then Multiple the Average Age X The Number of Deaths = YPLL

Front 34

Age-Adjusted Rate (Equation)

Back 34

Sum of [Age-Specific Rate * WT]

Front 35

Weighted Average

Back 35

In order to calculate WT, we take the population of the subgroup (Age Group) and Divide it by the Total population.

This will give us the weighted average that the particular group has within the total population

Front 36

SMR (Standardized Mortality Ratio)

Back 36

(Observed # of Deaths / Expected # of Deaths) X 100

Front 37

Expected Number of Deaths

(DIRECT METHOD)

Back 37

SUM of [Age-Specfic Death Rate X WT from Standard Population]

DIRECT METHOD: use the rate in the population you are watching

Hint 37

Answer!? Compare to 100. (i.e-- If answer is 240, that means the risk of getting the particular disease is 140% higher in this population than in the general public OR if the answer is 75, than the risk in this population is 25% lower than the gen pop.)

Front 38

Expected Number of Deaths

(INDIRECT METHOD)

Back 38

SUM of [Age-Specfic Death Rate X Number of Induviduals in the age group]

INDIRECT METHOD: use the rate in a standard population X # of the population you are watching now)

Front 39

Diagnosis

Back 39

To confirm wheter someone has the disease

Front 40

Screening

Back 40

To find someone among asymptomatic people for further test. (This allows for early detection and treatment)

Front 41

Sensitivity

Back 41

Test for all the people who TRULY DO have the diease

TP / (TP+FN)

Front 42

Specificity

Back 42

Test for all of the people who truly DO NOT have the disease

TN / (FP + TN)

Front 43

PPV (Positive Predictive Value)

Back 43

People (+) for diease & Test (+)

TP / (TP + FP)

Front 44

NPV (Negative Predictive Value)

Back 44

People without (-) for disease & Test Negative

TN / (TN +FN)

Front 45

Senstitivity vs. Specificity

Back 45

If you increase one, it will cause a decrease in the other.

Hint 45

Sensitivity & Specificity measure QUALITY!! (not quantity)

Front 46

Type I Error (Alpha Error)

Back 46

People who DO NOT have the disase, but test (+)

"Queen Latifah"

Hint 46

FP / (FP + TN)

Front 47

Type II Error (Beta Error)

Back 47

People who HAVE the disease, but test (-)

Hint 47

FN / (TP + FN)

Front 48

Gold Standard

Back 48

A method or procedure or measurement that is widely accepted as being the best available or the "reference standard"

Front 49

Accuracy

Back 49

(TP + FN) / (TP + FP + TN + FN)

Front 50

7 Principle for Screening Tests

Back 50

1. Important
2. Effective Therapy exists
3. Risk of Screening Low
4. Test has High levels of Sensitivity & Specificity
5. Test must be acceptable to the population
6. Disease must be Common
7. Test is Low Cost

Front 51

High Risk Population

Back 51

In order to efficient, Screening is normally carried out in High Risk Populations (Due to an Increased PPV)

Hint 51

i.e-- High Risk Population for Breast Cancer= Women over the age of 50 (as apposed to Males or Younger Women)

Front 52

Epidemiology

Back 52

The study of how disease is distributed in populations and the factors that influence or determine this distribution

Front 53

etiology

Back 53

Cause of Disease

Front 54

Primary Prevention

Back 54

Preventing the INITIAL DEVELOPMENT of a disease

Hint 54

Example:

Immunization, reducing Exposure to a Risk factor

Front 55

Secondary Prevention

Back 55

Early Detection of EXISTING DISEASE to reduce severity and complications

Hint 55

Example:

Screening for Cancer (Mammogram, Pap Smear)

Front 56

Tertiary Prevention

Back 56

Reducing the IMPACT OF THE DISEASE

Hint 56

Rehabiliation for Stroke