Surveillance Flashcards
Define health surveillance
The ongoing systematic use of collected data from health related events to guide public health action
State 6 processes of surveillance
Data collection, collation, analysis, interpretation, dissemination and action
Describe objectives of PH surveillance x6
Guide immediate action
Measure burden of disease
Monitor trend of burden of disease
Guide planning implementation and evaluation of disease control programs
Prioritize allocation of resource
Provide a basis for epidemiological research
Attributes of an ideal PH Surveillance system x5
Simplicity
Sensitivity
Stability
Usefulness
Representative
State the 5 types of surveillance methods
Passive or routine
Active
Sentinel health surveillance
Emergency
Serological and virological
Sources of bias in surveillance x4
Reporting propensity
Screening
Diagnostic methods
Attendance
Describe 2 support methods to enhance surveillance
Management- strengthen staff skills, recruit staff
Technology- access to internet and appropriate software
Describe the purpose of IDSR integrated disease surveillance and response
To improve ability of districts to identify and respond to outbreaks of priority infectious diseases using well known and available interventions
Describe 3 specific goals of integrated disease surveillance and response IDSR
Strengthen surveillance and response at district level
Integrate surveillance with laboratory support
Translate surveillance and laboratory data into public health actions
Define outbreak
The occurrence of cases of an illness clearly in excess of expectancy in a given place or group over a particular period of time
Sources of knowledge about an outbreak x4
Media
Health workers
General population
Routine analysis of PH surveillance
What is the purpose of investigating an outbreak x5
Prevention of further spread and control of outbreak
Research and training opportunities
To know the severity and population at risk
For program considerations
Public and political concerns
Describe the iceberg phenomenon
A situation in which a large percentage of a problem is subclinical, unreported, or otherwise hidden from view
Define cluster
Grouping of cases in a given place over a particular period of time
What are the causes of increased cases not indicative of an outbreak x4
Improved diagnostic procedures
Changes in case definitions and reporting procedures
Increased awareness of health workers
Increased interest because of media awareness
Seasonal population changes
Define case definition
A standard set of criteria for deciding whether a person should be classified as having the disease or condition
Describe the 3 epidemic curves used in outbreaks
Point source- steep up then down slope. Exposure over a brief period
Continuous common source- plateau instead of peak. Exposure over an extended period
Propagated -progressively taller peaks. Person to person spread
3 ways of implementing control and prevention in an outbreak
Interrupt transmission
Reduce susceptibility
Universal precautions PPE
What is the difference between efficacy, effectiveness and efficiency
Efficacy is getting things done
Efficiency is doing things in the most economic way
Effectiveness is the ability of a program to produce expected results
Difference between quarantine and isolation
Quarantine is restricting movement of exposed people to see if they get sick
Isolation separates sick people from those who are not
Define measures of association
A measure that quantifies the relationship between exposure and disease among 2 groups
Measures of association used in a cohort study x3
Absolute risk difference
Relative risk ratio
Odds ratio
Define relative risk/risk ratio
Ratio that compares the risk of an event among a specific group with the risk in another group
Purpose of case control studies
Determine if an exposure is associated with an outcome
Always retrospective
Define odd ratio in case control
Ratio of the odds of an exposure in the case group to the odds of an exposure in the control group
Define a confounder
A third variable that distorts association between an exposure and health outcome
Describe the concept of cause x2 necessity and sufficiency
A cause is termed sufficient when it inevitably produces or initiates a disease
It is termed necessary if a disease cannot develop in its abscence
Factors affecting causation x4
Predisposing factors
Enabling factors
Precipitating factors
Reinforcing factors
State the Bradford hill criteria
1.Temporal sequence of association- does cause precede outcome
2.Strength of association- less likely to be due to undetected confounding
3.Consistency of association
4.Biological gradient- increased risk f outcome with increased exposure
5.Specificity of association- single factor associated with single outcome
6. Plausibility of association- is association consistent with existing knowledge
7. Coherence- between epidemiological and laboratory findings
8. Reversibility- does removal of cause decrease risk of effect
9. Analogy- use of similarities between other associations
Purposes of PH surveillance x5
Recognize cases or clusters to trigger interventions
Demonstrate need for PH intervention programs and resources
Assess the Ph impact of health events
Monitor effectiveness of prevention and control
Identify high risk groups or geographical areas to target intervention
Define epidemiology
The study of distribution, frequency and determinants of health related events and use of this study to control health problems
Uses of epidemiology x4
Making individual decisions
Identify cause of a disease
Complete clinical understanding or disease
Assess community and population health
Core functions of epidemiology x4
Public health surveillance
Field investigation
Analytic studies
Evaluation
Policy development
Describe 2 types of categorical variables
Nominal- Data that can be classified into mutually exclusive categories within a variable
It has no order of ranking
Ordinal- variable that represents categories with a natural order of ranking eg education
Describe 2 types of numerical variables
Discrete- can only assume distinct values. Characterized by gaps eg hospital admissions
Continuous- can assume any value within a certain interval eg height
Types of tables used to display data x5
One, two and three variable table
Composite table
Statistics table
Table shells- layout without estimates
Types of graphs used to display data x5
Histograms
Cumulative frequency
Population pyramid
Arithmetic scale lines
Semi logarithmic scale lines
Describe two ways of organizing data
Line list- row and columns
Epi info- software package used to enter design edit and analyze data
Describe interval and ratio variables
Ratio- intervals that have a true zero
Interval- measured on a scale of equally spaced units and do not have a true zero
Describe frequency distribution and its properties x3
It displays a value and the number of persons with each value
1.Central location- clustering at a particular value. Measures mean median mode
2.Spread- scattering of data from one another. Measures range, S deviation, interquartile range
3.Shape
Define frequency measures and state 3 examples
Measures that compare one part of a distribution to another part of distribution
Rate, ratio, proportion
Describe morbidity frequency measures and their types x2
Incidence- number of new cases of a disease in a population at a given time.
Types: incidence proportion and rate
Prevalence-a proportion of people in a population who have a particular disease. Types: point prevalence and period prevalence
State measure of association x4
Risk ratio
Rate ratio
Odds ratio
Proportionate mortality ratio- proportion of deaths in a specified population over a period of time
Describe measure of PH impact and 2 used measures
It is a measure used to place an association between an exposure and an outcome into a meaningful PH context
Attributable proportions- measure of the public health impact of a causative factor
Efficacy- the ability to produce a desired or intended result
Reasons for conducting an outbreak investigation x3
Factors related to health problem- severity, mode of transmission
Factors relating to health department- staff and resources
Other- research and training
Indicator based surveillance
Regular identification, collection, monitoring, analysis and interpretation of indicators produced by a number of health based formal sources
State advantages of secondary data x3
Saves efforts
Low cost to access
Time saving
Disadvantages of secondary data x3
Lack of control over quality
Not specific to researchers needs
Out of date hence little or no relevance
State 2 things involved in assessment of health status problem
Analysis of precursors of the problem
Careful specification of the dimensions of the problem
State 3 properties of health indicators
Measurable - quantifiable
Malleable - responsive to change
Meaningful - in assessing key elements of health status
State 5 elements to involve in informed consent
A statement that the study involves research
The purpose of research explained
The duration of subjects participation
Description of procedures to be followed
Identification of any procedures that are experimental
State 8 components of a rapid response team
Clinician
Epidemiologist
Lab technician
Driver
Environmental health officer
Health education manager
Water development officer
Expert in industrial poisoning
Describe two types of numerical data
Interval - can be ranked or ordered. It does not have a meaningful zero. It can be negative eg temperature
Ratio - it has a rank and has a meaning zero but can never be negative eg age and weight
Describe the difference between cause and association
Association is the statistical relationship between 2 variables. Variables may be associated without a causal relationship
Cause is an event, condition or characteristic which plays a role in producing a disease
Define attack rate
The total number of new cases divided by the total population
Describe 2 characteristics of a scatter diagram
It requires more than one variable
It plots continous variables
A case definition should include x4
Time place and person
Clinical features
Does not include exposure
Define an observational case control study
A study on which subjects are enrolled on the basis of having or not having a health outcome
