Week 8: Principles and Application of Surveillance

Question 1

What is surveillance?

Answer 1

Continuous collection of data for analysis and interpretation to inform public health action.

Question 2

What are the purposes of surveillance?

Answer 2

• Detection of outbreaks and providing appropriate interventions to those in contact with certain diseases
• Monitor trends in disease and identify emerging threats
• Inform infection control and prevention programmes and evaluate public health policy
• Inform decisions about prioritisation of limited health resources
• Monitor disease outcomes to inform interventions

Question 3

List the principles of surveillance systems.

Answer 3

• Data collected must be justified by the contribution that is made to protecting the health of the population
• The design of a surveillance systems must address an activity or question
• The method of data capture, cleaning, analysis and reporting should be done in a consistent way
• Sufficient resources must be available for surveillance
• Transparent quality assurance processes should be in place
• The output of any surveillance system is based on the questions it needs to address
• Analysis and reporting of data must be transparent, accurate and in a format which informs action
• The surveillance system must work within the legal framework for collecting, storing and using an individual’s data

Question 4

What is the formula for prevalence?

Answer 4

Number of cases/population x 100

Question 5

What is the formula for incidence risk?

Answer 5

Number of new cases of disease in a specified period of time / number of disease-free persons at the beginning of that time period

Question 6

What is sentinel surveillance?

Answer 6

The monitoring of rate of occurrence of specific diseases and conditions through a voluntary network of doctors, laboratories and public health departments with a view to assess the stability or change in health levels of a population.

Question 7

List the advantages of sentinel surveillance.

Answer 7

• Cheaper to run
• More flexible

Question 8

When are sentinel surveillances used?

Answer 8

When a sample may accurately represent the whole population or when testing the whole population would be wasteful.

Question 9

What is syndromic surveillance?

Answer 9

Surveillance identifying diseases where the organism is not known and identifying syndromes and conditions associated with environmental factors such as air pollution or contaminated water.