Surveillance 1: concepts and methods

Question 1

Define montioring

Answer 1

Continuous effort to collect data to detect changes or treands in the occurence in order to inform decisions

Question 2

Define surveillance

Answer 2

A special case of monitoring where data are used to asses a status in response to a pre-defined threshold. Now there is a threshold above which we take action

Question 3

How to design a surveillance scheme

Answer 3

1. ) obejctive is monitoring
2. ) control program starts
3. ) monitoring becomes surveillance
4. ) surveillance used to assess the effectiveness of the control program
5. ) if eradication achieved, surveillance used to demonstrate freedom from infection

Question 4

Define ECDC

Answer 4

European Centre for Disease control

Question 5

Define survey

Answer 5

A mechanism of data collection, it can be a narrow or broad data gathering mechanism which can be used in either surveillance or monitoring

Question 6

What are the characteristics of surveillance systems?

Answer 6

Objectives
Hazard selection
case definition, diagnostic methods
target population
timing, sampling intervals
data management, analysis
methods for data analysis
feedback, dissemination of results

Question 7

What are the levels of Animal Health monitoring/surveillance? 4

Answer 7

National
Industry
Producer
Wildlife

Question 8

What are the levels of Animal Health monitoring/surveillance? 5

Answer 8

National
Industry
Producer

Question 9

Define ‘case’

Answer 9

An animal or unit that fulfills the specific definition based on clinical, laboratory or epidemiological characteristics.

Question 10

What are clinical criteria?

Answer 10

Sometimes used to define suspect cases that have become confirmed cases following laboratory confirmation

Question 11

What are epidemiological criteria?

Answer 11

Farms defined as potential cases on the basis of location with respect infected farms of dangerous contacts with infected farms

Question 12

Define outbreak

Answer 12

Cases clustered in time and space, occurring at higher level than expected

Question 13

Define epidemic

Answer 13

Occurrence of more cases of disease than expected in a given area or among a specific group of people over a particular period of time

Question 14

Define pandemic

Answer 14

‘an epidemic occurring worldwide, or over a very wide area, crossing international boundaries and usually affecting a large number of people’.

Question 15

Define incidence

Answer 15

The rate of disease. e.g. 2 cases/700,000 cattle/year

Question 16

Define prevalence

Answer 16

The proportion of infected cases. e.g. 2 cases per 2,500 tested.

Question 17

Define internal validity

Answer 17

measuring what is happening in your sample on the farm

Question 18

What is external validity?

Answer 18

extrapolating results from your sample farm to the general population

Question 19

Define bias

Answer 19

a systematic error due to the design, implementation or analysis of the surveillance program. Different from random error which is due to sampling variation.

Question 20

What are 3 types of bias?

Answer 20

Case detection
Selection bias
Information bias

Question 21

What is the clinical iceberg?

Answer 21

Deaths < severe disease < moderate disease < mild disease < sub-clinical disease

Question 22

Define sensitivity

Answer 22

Sensitivity (also called the true positive rate, or the recall rate in some fields) measures the proportion of actual positives which are correctly identified as such (e.g., the percentage of sick people who are correctly identified as having the condition), and is complementary to the false negative rate.

Question 23

Define specificity

Answer 23

Specificity (sometimes called the true negative rate) measures the proportion of negatives which are correctly identified as such (e.g., the percentage of healthy people who are correctly identified as not having the condition), and is complementary to the false positive rate.

Question 24

UK examples of motinoring

Answer 24

Production performance records

Medicine use records

Question 25

UK examples of surveillance

Answer 25

Milk quality testing (SCC)
Residue testing
TB testing
Salmonella testing
Brucella melitensis testing
Voluntary disease control programs (BVD, JD)
SPF programmes

Question 26

What are SPG programmes?

Answer 26

Specific Pathogen Free Programmes

Question 27

List 4 examples of competent authorities

Answer 27

Animal Health
Rural Payment Agency
Local Authorities
Rural Inspectorate for Wales

Question 28

What is the reporting pathway for a statutory (notifiable) disease)?

Answer 28

Owner –> veterinarian –> Animal Health Division Office –> DEFRA –> EU/OIE

Question 29

Define notifiable disease

Answer 29

those where there is a statutory requirement to report a suspicion of a clinical case of disease

Question 30

Define reportable disease

Answer 30

(in animals) are those where there is a statutory requirement to report laboratory confirmed isolation of organisms of the genera Salmonella and Brucella under the Zoonoses Order 1989. The report is to be made by the laboratory which isolated the organism from an animal derived sample.

Question 31

What happens in practice if you suspect signs of a notifiable disease?

Answer 31

You must immediately notify the local Animal Health DVM, generally by contacting the local Animal Health office and speaking to the duty vet