1- Applied epidemiology

Question 1

Define Epidemic

Answer 1

The occurrence in a community or region of cases of an illness, specific health-related behaviour, or other health related events clearly in excess of normal expectancy

Question 2

Define endemic

Answer 2

The constant occurrence of a disease, disorder or noxious infectious agent in a geographic area or population group, it may also refer to the chronic high prevalence of a disease in such area or group

Question 3

Define contagious disease

Answer 3

A disease transmitted by direct or indirect contact with a host that is the source of the pathogenic agent. The same disease can be contagious in some species and not in others

Question 4

Define communicable disease

Answer 4

A disease whose casual agent can be transmitted from successive hosts to healthy subjects, from one individual to another

Question 5

Define morbidity

Answer 5

Any departure, subjective or objective, from aa state of physiological or psychological well-being.

Question 6

Define mortality

Answer 6

the state of being subject to death

Question 7

Define positive predictive value

Answer 7

The probability that a person with a positive test result is a true positive

Question 8

Define negative predictive value

Answer 8

The probability that a person with a negative test result is a true negative

Question 9

Define prevention

Answer 9

Actions that prevent disease occurrence

Question 10

Define eradication

Answer 10

termination of all transmission of infection by extermination of the infectious agent through surveillance and containment

Question 11

What is the R number

Answer 11

Basic reproduction
The average number of cases infected by a primary case when the population is naive

Question 12

What is the R number of endemic diseases?

Answer 12

Endemic disease = Disease found in/restricted to a particular region

R0 <1 (Average number of cases inf. is less than one)

Question 13

Questions to ask when approaching a disease investigation?

Answer 13

How many cases?
Are all animals/people at risk?
In what areas?
Over what time?
Are there specific subgroups that are more likely to be infected?

Question 14

Epidemic curve:
What structure does the curve have if a common exposure is identified? (Food poisoning)

Answer 14

Rapid increase in cases > Then tight clustering of cases

Question 15

What are case-control studies?

Answer 15

Compare between cases and non-cases (Diseased and non-diseased)
Look retrospectively at the differences in exposure to risk factors

Question 16

What are cohort studies?

Answer 16

Looks at individuals exposed and not exposed to risk factors and see if they develop the disease

Question 17

What is an odds ratio?

Answer 17

Odds of the disease in the exposed group vs with odds of the disease in the unexposed group.
common in disease control studies

Question 18

What is a relative risk ratio?

Answer 18

Comparison between the risk of an outcome in the exposed group vs in the unexposed group

Question 19

Describe the ‘test and remove’ strategy of disease eradication

Answer 19

Animals testing positive are removed and slaughtered

Question 20

Describe the ‘pre-emptive’ strategy of disease eradication

Answer 20

○ Animals that have been exposed to infection are slaughtered

Question 21

Describe the ‘blanket culling’ strategy of disease erdaication

Answer 21

Animals on contiguous premises surrounding an infected farm are culled

Question 22

Describe the ‘stamping out’ strategy of disease eradication

Answer 22

Combination of:
Test and removal
Pre-emptive
Blanket culling
as well as other preventative measures

Question 23

What is the R number in epidemic disease

Answer 23

R0 > 1
The average number of cases infected by a primary case is greater than 1

Question 24

If OR>1 what does this suggest

Answer 24

Risk factor not associated with disease

Question 25

If RR>1 what does this suggest

Answer 25

RF associated with disease