Module 3

Question 1

Disease definition

Answer 1

Interruption, cessation or disorder of body functions systems or organs

Question 2

Etiology

Answer 2

The study of causation or origination. The study of why things occur

Question 3

Disease classifications -2

Answer 3

1. Infectious: you can catch it from another

2. Noninfectious: non contagious

Question 4

Sensitivity

Answer 4

Proportion of individuals who truly have the dx and are tested positive

TP/ TP + FN

Question 5

Specificity

Answer 5

Proportion of those who truly do not have the dx and are tested negative.

TN / TN+FP

Question 6

Positive predictive value

Answer 6

TP/TP+FP

The proportion of true positive tests out of all positive

Question 7

Negative predictive value

Answer 7

tN/TN+FN

The proportion of true negative tests out of all negatives

Question 8

Endemic

Answer 8

Ongoing usual level or constant presence of a disease within a given population or geographical area

Question 9

Two types of estimation and definitions

Answer 9

1. Point estimate, the best single number estimate

2. Confidence interval estimate, range of values or confidence is attached

Question 10

Mean

Answer 10

Average of all numbers which shows central tendency, This is affected by outliers

Question 11

Relationship between sensitivity specificity positive and negative predictive value

Answer 11

If we increase sensitivity we reduce specificity and vice versa. Increased specificity affects the positive predictive value inversely and increased specificity has the same effect with negative predictive values. This can help an epidemiologist determine the effectiveness of a screening method and the PPV and NPV help detect how feasible it is. If there is a lot of false positive or negative’s the test is not very accurate and specificity or sensitivity needs to be adjusted

Question 12

Epidemic

Answer 12

Rapid spread of disease within a short period of time that is higher than what is expected in a population

Question 13

Pandemic

Answer 13

An epidemic that has spread beyond the immediate population over entire countries, affects many people and can be global.

Question 14

Strategy to control a disease outbreak that impacts multiple countries

Answer 14

Stop transportation in and out of country until the outbreak is controlled.

Establish programs to help test and treat as many at risk ill people as possible.

Shut down large events where people gather in large numbers.

Implement educational campaigns to teach those at risk how to avoid illness.

Question 15

Three types of transmission of infectious dx

Answer 15

Contact, vehicle, vector

Question 16

Contact transmission (3 types)

Answer 16

Direct: immediate transfer of an agent from the host or reservoir to a susceptible host (ex kissing or sex) mono, AIDS

indirect: agent is transferred or carried by an intermediate item, organism, means, or process to a susceptible host, resulting in disease (ex dirty cup or tissue) common cold, hepatitis (dirty needle)
droplet: organisms are in droplets produced by sneezing coughing and talking, don’t travel far. Common cold.

Question 17

Vehicle transmission (two types)

Answer 17

Transmission of disease agents by medium such as water food or air, two types

Waterborne: carried through water. Cholera.

airborne: droplets or dust particles carried the pathogen to host, Travel more than a meter in air. Fungal spores, measles.

Question 18

Vector transmission (2 types)

Answer 18

Animals that carry pathogens from one house to another- 2 types

Mechanical: pathogen uses a separate host to physically transfer disease (ex on feet or body parts)
, passive transmission.

biological: pathogen undergoes changes as part of its lifecycle well within the host or vector before being transmitted to a new host. Transmitted through bite, vomit, or fecal matter. Example, Lyme disease and malaria

Question 19

Stages of natural history of disease

Answer 19

1. Stage of susceptibility, well (primordial, primary prevention)
2. Preclinical, at risk (secondary)
3. Clinical, Symptom onset and usual diagnosis (secondary)
4. Post clinical phase, chronic (tertiary)

Question 20

Ratio variable

Answer 20

This variable has a scale with an inherent order and a true zero

example is height and weight

Question 21

Interval variable

Answer 21

Variable with definitive intervals

Example is temperature measured in degrees Celsius

Question 22

Ordinal or ranked variable

Answer 22

More than two responses that are ordered

Example is how happy are you with your service? 1. Extremely happy 2. Happy 3. Neutral 4. Unhappy 5. Very unhappy

Question 23

Nominal or categorical variable

Answer 23

More than two responses that are not ordered

What make of car do you have? 1. Honda 2. Ford etc…

Question 24

Binomial variable

Answer 24

Also known as dichotomous variable, a nominal variable with only two outcomes

Example is success or fail

Question 25

Disease transmission chain and definitions

Answer 25

1. Agent, What is considered infectious, the bacteria viruses etc.
2. Reservoir, sores that provides conditions for the survival multiplication and transmission to others.
3. Mode of transmission, the process that the agent infects the host
4. Host, where the infectious agent is able to live and thrive

Question 26

Surveillance

Answer 26

Systematic ongoing collection, analysis, interpretation, and dissemination of health data. First developed for infectious disease.

We need to know normal and expected in order to identify changes in occurrence in distribution of disease. Important for tracking long-term trends describing natural history of disease, identifying epidemics or new diseases, identify areas for research, planning public policy

Question 27

Four types of surveillance

Answer 27

Active, Actively look for cases of disease in community, Health department contacting healthcare providers or laboratories, requesting information about conditions or diseases. Requires more resources

Passive, relying on mandatory disease reporting. Efficient, simple, and inexpensive. May have incomplete data due to underreporting though.

Question 28

Epi triangle (3 parts)

Answer 28

1. Agent (bacteria)
2. Environment (hot climate) external factors that allow transmission
3. Host (human) organism harboring the disease

Center of triangle is the vector (mosquito) person animal micro organism that carries and transmits pathogen

Question 29

Advanced epidemiological triangle, Three parts

Answer 29

1 Causative factors

2. environment behavior and culture physiological factors ecological elements
3. Group or population and their characteristics

Center of triangle is time

Question 30

Zoonosis

Answer 30

An infection or infectious disease transmittable under natural conditions from vertebrae animal to human

Question 31

Emerging infectious diseases

Answer 31

AIDS, Lyme disease, Cholera, hantavirus pulmonary syndrome, passage fever, Ebola. Reemergence of influenza, malaria, pertussis, rabies, tuberculosis, yellow fever

Question 32

Reasons for emerging infectious diseases today

Answer 32

Globalization, poverty, increase in population density, travel, long-distance trade, weather and climate changes

Question 33

Continuous variable

Answer 33

Unlimited responses, defined minimum and maximum value in responses can be anywhere in between. Sample, what is your weight?