Classes 3-7 - Descriptive Epi and Measures of Disease Freq Flashcards
Descriptive Epidemiology
Who/Where/When?
Used to determine if site/location is experiencing a disease occurrence more frequently than usual at that locale
Passive surveillance system
Relies on healthcare system to follow regulations on required reportable diseases/conditions
Public health system passively waits for reports to come in, in order to track disease freq over time and w/in populations
Active surveillance system
Public health officials go into community to search for new disease/condition cases
Syndromic Surveillance System
System that looks for pre-defined signs/symptoms of patients, either being reported or evaluated.
Biosurveillance
How government refers to syndromic surveillance when dealing with bioterrorism
Look for signs/symptoms in humans, animals, plants, and envir
Case Definitions
A set of uniform criteria used to define a disease/condition for public health surveillance.
Why are case definitions necessary?
Enables public health to classify and count cases consistently across reporting jurisdictions
Epidemic
Increased # of disease occurrences compared to normal occurrences
Outbreak
More isolated/concentrated occurrence of epidemic
also called cluster
What is it considered when many outbreaks occur in different areas?
Epidemic
Endemic
Constant high occurrence of disease in one area or population than in other areas
Example of Endemic
HIV in Africa
Pandemic
An epidemic occurring over a very wide area involving a large number of people
Generally crosses continents
Example of Pandemic
Swine Flu (H1N1)
What types of illnesses make up most of pandemics?
Viruses
The Epidemic curve
Visual depiction created during an outbreak/epidemic of the # of cases by date of onset
What do epidemic curves visually depict?
Pattern of spread (shape)
Magnitude of impact
How do epidemic curves help?
Helps form hypotheses
- Routes of transmission
- Probably exposure period
- Incubation period (may help identify/eliminate causes)
Common or point source
Not person to person spread
Derived from a common, single point source for outbreak
Can be continuous or intermittent
Propagated source
Person to person spread
Generally occurs with illnesses that have longer incubation times
Infected subjects infect others (secondary) who then infect others (spread)
Sentinel/index case
Single case that outbreak derived from
Distribution of Disease
Frequency and pattern (person,place,time)
