Surveillance 1 - Concepts and Methods

Question 1

How does monitoring differ to surveillance?

Answer 1

Monitoring - collecting data to see changes/trends and inform decisions

Surveillance - monitoring where data is used to assess status in response to a threshold and above this threshold ACTION is taken

Question 2

What is a common reason for ineffective surveillance?

Answer 2

When the case definition is imprecise or not consistently used.

Question 3

Are herd health plans monitoring or surveillance?

Answer 3

Surveillance programs

Question 4

What steps may lead to the implementation of surveillance?

Answer 4

1. Monitoring,
2. Control program starts and
   3 Monitoring becomes surveillance
3. As incidence decreases surveillance continues - possibly resulting in eradication
4. Surveillance may continue once eradicated but with different objective - to demonstrate freedom from infection (TRADE!)

Question 5

Generally, what is the objective of surveillance on a farm?

Answer 5

The objective is to optimise productivity, this is a good tool for measuring animal health as well.

Question 6

What do farm level surveillance systems rely on?

Answer 6

Farm records and the farmer being able to control the diseases

Question 7

What are some main objectives of surveillance with regards to animal health?

Answer 7

Demonstrating freedom from disease (national)
Detecting outbreaks (National)
Monitor production disease (Industry and Producer)
Monitor zoonoses and food borne disease (Industry)
Establish disease status (Wildlife)

Question 8

What are some main objectives of surveillance with regards to food safety?

Answer 8

Progress of hazard reduction programs (national)

Assure freedom from hazard (industry/producer)

Question 9

How can cases be defined?

Answer 9

Based in clinical, laboratory or epidemiological characteristics

Question 10

What is meant by the term outbreak?

Answer 10

Cases clustered in time and space occuring at a higher level than expected

Question 11

How does incidence differ to prevalence?

Answer 11

Incidence gives a rate. I.e. i is the number of new cases occuring.

Prevalence just refers to the number of existing cases at a point in time - therefore it offers limited information about the cause of disease.

Question 12

What is meant by:

a) Internal Validity
b) External validity

Answer 12

a) That what is being recorded is correct

b) That extrapolated data is representative of the population as a whole.

Question 13

Is active or passive monitoring more likely to be biased?

Answer 13

Passive as it relies on the reporting of cases.

Question 14

Why is surveillance carried out?

Answer 14

To protect:
Public health
Animal health and welfare
Environment/wider society
International Trade

Question 15

What can be submitted to a veterinary investigations centre for analysis?

Answer 15

1. Carcasses for surveillance

2. Postal samples

Question 16

What can carcase submission help to identify?

Answer 16

Level of endemic disease
Animal Welfare Issues
Notifiable Diseases
Novel Diseases (e.g. schmallengberg)
Zoonoses
Chemical Threats to food chain
Antibiotic resistance
ADRs

Question 17

What scanning surveillance method(s) is/are used within the APHA?

Answer 17

Submission forms and the Farmfile database. Forms submitted by the veterinary practitioner. It is used to standardise data collection. Adding to the database allows passive surveillance.

Question 18

What is targetted surveillance?

Answer 18

Where a case has been identified and further carcasses are collected for follow up investigation. This is a more active approach than scanning surveillance.

Question 19

What is the issue with scanning surveillance?

Answer 19

It will only give the ‘tip of the iceberg’ as it relies on reporting going further up the reporting pyramid. This can be dependent on costs and on adequate tests being available for eg.

Question 20

In summary, what are the roles of a VIC?

Answer 20

National disease surveillance to protect public & animal health, animal welfare, international trade and the environment.

Provide standardised, quality assured tests
-Dx support for vets by providing subsidised PMs

Analyse and interprets surveillance data

Informs stakeholders to take action

Provides advice to practitioners