Surveillance 1: concepts and methods Flashcards
Define montioring
Continuous effort to collect data to detect changes or treands in the occurence in order to inform decisions
Define surveillance
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
How to design a surveillance scheme
- ) obejctive is monitoring
- ) control program starts
- ) monitoring becomes surveillance
- ) surveillance used to assess the effectiveness of the control program
- ) if eradication achieved, surveillance used to demonstrate freedom from infection
Define ECDC
European Centre for Disease control
Define survey
A mechanism of data collection, it can be a narrow or broad data gathering mechanism which can be used in either surveillance or monitoring
What are the characteristics of surveillance systems?
Objectives Hazard selection case definition, diagnostic methods target population timing, sampling intervals data management, analysis methods for data analysis feedback, dissemination of results
What are the levels of Animal Health monitoring/surveillance? 4
National
Industry
Producer
Wildlife
What are the levels of Animal Health monitoring/surveillance? 5
National
Industry
Producer
Define ‘case’
An animal or unit that fulfills the specific definition based on clinical, laboratory or epidemiological characteristics.
What are clinical criteria?
Sometimes used to define suspect cases that have become confirmed cases following laboratory confirmation
What are epidemiological criteria?
Farms defined as potential cases on the basis of location with respect infected farms of dangerous contacts with infected farms
Define outbreak
Cases clustered in time and space, occurring at higher level than expected
Define epidemic
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
Define pandemic
‘an epidemic occurring worldwide, or over a very wide area, crossing international boundaries and usually affecting a large number of people’.
Define incidence
The rate of disease. e.g. 2 cases/700,000 cattle/year
Define prevalence
The proportion of infected cases. e.g. 2 cases per 2,500 tested.
Define internal validity
measuring what is happening in your sample on the farm
What is external validity?
extrapolating results from your sample farm to the general population
Define bias
a systematic error due to the design, implementation or analysis of the surveillance program. Different from random error which is due to sampling variation.
What are 3 types of bias?
Case detection
Selection bias
Information bias
What is the clinical iceberg?
Deaths < severe disease < moderate disease < mild disease < sub-clinical disease
Define sensitivity
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.
Define specificity
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.
UK examples of motinoring
Production performance records
Medicine use records
