Intro into Epidemiology

Question 1

What are epidemiological principles essential for understanding?

Answer 1

• spread of disease in populations, and how to manage this
• occurrence of complex diseases and productivity problems
• impact of disease on populations

Question 2

What two sources of evidence should be used for decision making when practicing evidence based veterinary medicine?

Answer 2

Internal: your own clinical experience and expertise (your experience alone becomes narrow and may become outdated)

External: Evidence from other research (alone, this may be irrelevant without your clinical experience)

Question 3

What is epidemiology?

Answer 3

The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems

Question 4

Veterinary epidemiology deals with the investigation of diseases, _______, and _______ in the animal populations

Answer 4

productivity and welfare

*it describes the frequency of occurrence of these health-related states/events and how dzs, productivity, and welfare are affect by different factors or determinants

Question 5

What is the primary goal of veterinary epi?

Answer 5

To reduce the frequency of dz occurrence, enhance productivity, and improve animal welfare

Question 6

What must you answer to describe the distribution of health related states/events? (4 Ws)

Answer 6

Who
what
when
where

study the natural history of the dz and describe the prognosis of the dz

Question 7

What must you answer to identify determinants of health related outcomes?

Answer 7

WHY

Identify causes and risk factors of dz and health

Evaluate preventative and therapeutic measures

Question 8

T/F: Veterinary epidemiology focuses very much on the individual

Answer 8

FALSE

Focus is on populations, herds, farms, shelters, etc

Question 9

The clinical approach focuses on the ______

Answer 9

Individual

*success depends on the disease being known and correct diagnosis/or list of diagnoses

Question 10

What is the epidemiological approach of thinking?

Answer 10

Focuses on groups

1. Describes those individuals in a pop with dz and those with less dz
2. Look for differences between the groups
3. Apply measures to reduce contributing factors

** success without known the etiological agent

Question 11

T/F: The best approach in vet med is to used a clinical and epidemiological approach combination

Answer 11

TRUE

Question 12

Who is the “father of epi” and dz outbreak did he work on?

Answer 12

John Snow

Cholera outbreak in London 1853 - he investigated the cases of cholera deaths and where they received their water supply from

Question 13

Fill in the blanks (descriptive or analytical)

John Snow started with _____ epi, obtaining information on the numerator (# of cholera deaths) and the denominator (# of people supplied with water)

Then he used ______ epi to compare the death rates of cholera in the two different areas

Answer 13

1. descriptive

2. Analytical

Question 14

What form of epidemiology describes the disease or other health related events (answering the What, Who, When, and where)?

Answer 14

Descriptive epi

Question 15

What form of epi determines if there is an association between an exposure and outcome in a population and how strong the association is (the WHY)?

Answer 15

Analytical

Question 16

In descriptive epi, what is the case definition?

Answer 16

Standard criteria for categorizing an individual as a case
**avoids subjectivity

This is important in answering the WHAT: the health/production/or welfare issue of concern

Question 17

How do you answer the WHEN when using descriptive epi?

Answer 17

Can be looked at many different ways pending on the dz/health issue you are looking at.. could be:

• Changing or stable rates of dz
• Clustered in time or evenly distributed
• Single point source or intermittent exposure
• Seasonal variation

Question 18

What are some exampled of WHERE when using descriptive epi?

Answer 18

• geographic location - restricted or widespread
• relation to a food or water supply
• Clustered or evenly distributed

*one room or whole barn
etc

Question 19

What are some limitations of descriptive epi?

Answer 19

• cannot formally ID associations between exposure and outcome
• cannot infer causality

PRO - can be useful to generate hypotheses for future testing/studies

Question 20

Case reports, Case series, and cross sectional studies are all examples of what kind of epidemiological studies?

Answer 20

Descriptive

Question 21

_______ epidemiology is aimed at identifying and determining the strength, importance, and statistical significance of associations between exposures and health related outcomes

Answer 21

Analytical

Question 22

What is an association?

Answer 22

There is an association between an exposure and an outcome when they are dependent on one another

*an identifiable relationship between an exposure and outcome

Question 23

T/F: Epi determines the cause of a disease in a give individual

Answer 23

FALSE

It determines the relationship or association between a given exposure and the frequency of disease in populations

Question 24

Causation implies that there is a ____ mechanism that leads from the exposure of the disease

Answer 24

True

Question 25

Who and what are involved in the epidemiological triad?

Answer 25

Host
Agent
Environment

This is a model of disease causation but is not adequate for diseases that appear to have multiple contributing causes without a single necessary one

Question 26

What model of disease causation is used to represent a disease caused by multiple factors; when a host is exposed to all these factors (not necessarily at the same time), disease occurs

Answer 26

Rothman’s model (casual pies)

*individual factors are component causes - all those combined = sufficient cause of disease

Question 27

What is the Bradford-Hill criteria used for?

Answer 27

Determining whether an association is causal

Criteria includes:
Temporal relationship
Strength of association
Dose-response relationship
Replication of findings
Biological plausibility
Consideration of alternative explanations
Cessation of exposure
Specificity of the association 
Consistency with other knowledge