Epidemiology

Question 1

What is epidemiology?

Answer 1

Study of disease in populations

Question 2

What do epidemiologists do?

Answer 2

• Limit effects of disease in a population
• Reduce/ control amount of disease
• Protect populations from disease

Question 3

What is an endemic disease?

Answer 3

Commonly found in, or restricted to a particular region, community or group of people
R0<1 (average number of cases infected by primary case less than 1)

Question 4

What is an epidemic disease?

Answer 4

Level of disease in a population significantly greater than usual
R0>1

Question 5

What does R0 mean?

Answer 5

Reproduction or transmissibility rate

Question 6

What is meant by odds ratio?

Answer 6

• Odds of the disease in the exposed group compared with odds of the disease in the unexpected group
  OR<1 (not associated with disease)
  OR>1 (associated with disease)

Question 7

What is meant by relative risk?

Answer 7

Ratio of risk of disease in exposed group to risk of disease in unexposed group
RF<1 (not associated with disease)
RF>1 (associated with disease)

Question 8

What sub typing genetic tests can be used in epidemiological studies?

Answer 8

• PCR
• DNA sequencing
• designed to detect and identify pathogen genetic material

Question 9

What are the advantages of typing methods?

Answer 9

• Increased sensitivity/ specificity of diagnosis
• Faster tests
• Good for M.bovis/ prions (things hard to culture)
• Outbreaks can be detected/ therefore controlled at an earlier stage
• Can identify carriers

Question 10

What is meant by disease eradication?

Answer 10

• Complete eradication of disease, or disease agent from a region

Question 11

What environmental measures can you put in place to decrease pathogen transmission?

Answer 11

• Restriction of host movement
• Quarantine/ isolation
• Control of vectors (e.g. ticks)
• Biosecurity

Question 12

What disease controls can you apply to the host?

Answer 12

• Vaccination

- Modification of host resistance (e.g. the national scrapie plan -resistant genotypes)

Question 13

Describe the different methods of disease eradication

Answer 13

• Test/ removal: animals testing positive and slaughtered
• Pre-emptive: animals exposed to infection are slaughtered
• Blanket culling: animals on contiguous premises surrounding infected farm are culled.
• Stamping out: combination of one of the above measures

Question 14

List different groups involved in an outbreak control team

Answer 14

• LA environmental health
• PHE
• FSA
• APHA