Community Midterm

Question 1

Endemic

Answer 1

Habitual presence of disease in a defined geographic area. High background rate of disease. (ie obesity, some STIs, malaria in some parts of the world, lyme disease in certain regions)

Question 2

Epidemic

Answer 2

The occurrence in a community or region of a group of illnesses of similar nature, clearly in excess of normal expectancy, and derived from a common or propagated source. (AKA outbreak!)

Question 3

Pandemic

Answer 3

Widespread, often global

Question 4

What to do when there is an outbreak investigation?

Answer 4

• Establish and verify diagnosis of reported cases
• Search for additional cases - collect daata
• Describe and orient date in terms of time, place, person
• Formulate and test hypothesis
• Refine hypotheses and carry out additional studies (sometimes)
• Implement control and prevention measures
• Evaluate control measures
• Communicate findings

Question 5

Epidemic curves can tell you…

Answer 5

• Distribution of the times of onset of the disease
• Type of disease process
• Pattern of spread
• Magnitude
• Time trend
• Exposure and/or incubation period

Question 6

Epidemic Curves (4 types)

Answer 6

Person to person: Propagated

Common source: Point Source, Continuous, Intermittent

Question 7

Point Source

Answer 7

Outbreak that is short term, and a one time exposure.

Question 8

Continuous

Answer 8

Common source that is a contributing factor, but the exposure happens over a prolonged period of time. Ex: contamination in the water, continue to get sick until you remove the source of infection.

Question 9

Intermittent Source

Answer 9

Common source, but spread out over time. Ex: Salmonella. Small peaks, then no outbreak, then another few cases, then no outbreak. Peaks not getting bigger, staying spread apart.

Question 10

Propagated

Answer 10

One person gets disease, infects a group of people, they infect more people. Peaks get bigger and bigger as exponentially more people become infected. Communicable disease. Ends due to herd immunity, generally.

Question 11

Attack Rate Formula

Answer 11

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

• numerator: cases, case definition
• denominator: population at risk
• calculate attack rate

Question 12

Screening

Answer 12

Primary objective: detection of a disease in its early stages to treat it and deter its progression

Secondary objective: reduce cost of disease management by avoiding costly interventions at later stages.

Question 13

Types of Screening (3)

Answer 13

Mass - to an entire population (cholesterol screening at a health fair)

Selective (targeted) - for high risk populations (TB in health care workers)

Periodic - screen a discreet but well subgroup of the population on a regular basis over time for predictable risks or problems (cervical cancer screening, lead screening)

Question 14

Advantages of Screening

Answer 14

Simplicity
Target individuals or groups
Options of one-test or multiple-test screening
Opportunity for health education

Question 15

Disadvantages of Screening

Answer 15

Not 100% accurate. Will be fas positives and false negatives.

Question 16

Implications of Screening

Answer 16

False Positive: undue worry, stigma, more invasive testing, unnecessary treatment

False Negative: may lose opportunity for early intervention, may engage in risky behavior due to “negative” status

Question 17

Selection of a Screenable Disease

Answer 17

Significance: is it really a public health concern? Level of threat? How many people are affected?

Detection: can we screen for this disease?

Should screening be done? What does the evidence say? What is the benefit of knowing? Is treatment available/really needed?

Question 18

Sensitivity

Answer 18

True Positives/
(True Positives + False Negatives)

Has N in word but has to do with Positives!

Question 19

Specificity

Answer 19

True Negatives/
(True Negatives + False Positives)

Has P in word but has to do with Negatives!

Question 20

True Positives

Answer 20

Person has the disease and the test says they do

Question 21

False Positive

Answer 21

Person doesn’t have the disease but the test says they do

Question 22

True Negative

Answer 22

Person doesn’t have disease, test says they don’t

Question 23

False Negative

Answer 23

Person does have the disease, test says they do