one health lecture 5- surveillance Flashcards
what is monitoring in surveillance?
-Routine collection of information on disease
-Often a defined population and time period
-More descriptive and less systematic than surveillance
-Doesn’t necessarily lead to action
what is the difference between eradication and elimination?
Eradication - permanent and global, only happened twice
-Smallpox
-Rinderpest
Elimination - restricted to a specific geographic area
when is a disease confirmed as eliminated?
-no cases for over 10 years but is this due to lack of detection or true absence?
what are the types of surveillance?
-passive
-active = of notifiable diseases and target diseases
-syndromic
what is active surveillance?
-health department (or other authority) proactively contacts health care providers or laboratories requesting information about specific diseases
-more costly and labour-intensive
-tends to provide a more complete estimate of disease frequency
what are notifiable disease?
-Legal duty to report
-Within 24-72 hours, depending on level of urgency
-Diseases with high public health or economic implications
-Often “exotic” (transboundary diseases)
-On basis of clinical suspicion
-Urgent 0 within 24 hours
-Routine – within 3 days
what is bovine tuberculosis?
endemic – already present in the UK, such as bovine TB; Scotland officially free since 2009
Transmission can occur through nose to nose contact and also through contact with saliva, urine, faeces and milk.
exotic – not normally present in the UK, such as foot and mouth disease
Contingency plans…
what is targeted surveillance?
-Directed at particular at-risk individuals
Example: cancer screening for those with family history
-Helps improve health outcomes
Early detection ~ more effective treatment options
what is passive surveillance?
Regular reporting of observed cases but no active search
-minimum standard, present in most countries
-relatively cheap
-expect underreporting
In contrast to active surveillance (which aims to determine true incidence)
Includes “ad-hoc” reporting (e.g. citizen science)
what are the challenges with wildlife disease surveillance?
-Observing and reporting of cases
-Remoteness
-Scavengers
-Topography (landscape) Etc.
what is syndromic surveillance?
-Look for rise in the number of people reporting particular types of symptoms, e.g. febrile illness (fever)
-Syndromic surveillance systems monitor data from school absenteeism logs, emergency call systems, hospitals’ over-the-counter drug sale records
-Monitor trends on web or other data collection platforms => “nowcasting”
what is laboratory based surveillance?
-Diagnostic confirmation of aetiology (cause) of disease
-More specific than syndromic surveillance
Can detect:
-Pathogen (culture)
-Nucleic acid (PCR)
-Antibodies (ELISA) –> exposure
what are the 2 hypotheses about where our own pathogens come from?
1- Co-evolution: pathogens inherited from our ancestors
2- Cross-species transmission: more recent introductions from other species
For most human infectious diseases, genetic data support the second hypothesis
what are the 2 ways to predict zoonotic disease emergence?
1- Cataloguing all wildlife pathogens and identify the ones most likely to emerge
2-Better surveillance systems (especially in high-risk regions) to detect emergence as it happens
why do surveillance?
1- Gaining basic understanding of epidemiology
2- Early warning system (detect outbreaks)
3- Tracking interventions (assess impact)
4- Inform policy and practice
5- Monitoring variants (e.g. drug resistance)
