BIOL 437 Week Four Part 2 Flashcards
epidemic curve
- histogram
- shape can suggest hypothesis
- incubation period
incubation period
-time between exposure and onset of symptoms
common source types
- point: same exposure over limited time period
- intermittent
- continuous
propagated (simple)
-spread from person to person
mixed epidemics (simple)
-a mixture of common source and propagated
common source
-tend to result in more cases occuring more rapidly
>sooner than host-to-host epidemics
-removing exposure to common source typically causes the epidemic to rapidly decrease
examples of common source
- anthrax: milk or meat from infected animals
- botulism: traced to soil-contaminated foods
propagated
- arise from infections being transmitted from one infected person to another
- indirect or direct transmission
- host-to-host epidemics rise and fall more slowly than common source
examples of propagated
- tuberculosis
- whooping cough
- influenza
- measels
- covid-19
mixed epidemics
- occurs when a common source is followed by person-to-person contact
- disease is spread as a propagated outbreak
ex. shigellosis
time-series analyses
-ecologic: group level
-longitudinal data: individual level
>age effect
>cohort effect
>period effect
time-series design
- searching for patterns of disease over time
- secular trend/temporal variation
- cyclic patterns
cyclic patterns
-recurrent alterations in the occurence, interval or frequency of diseases
>seasonality
-periodic increases and decreases in occurence
types of trends
- secular
- short term
- cyclic patterns/trends
secular trends
-represent long-term changes in health-related states or events
short-term trends
-usually brief, unexpected increases in health-related states or events
surveillance types
- medical: individual level
- public health: population level
public health surveillance
-systematic ongoing collection, analysis, interpretation and dissemination of health data
monitor
- identify sudden changes in occurence
- follow long-term trends and patterns
- identify changes in risk factors
as a result of monitoring
-we identify wheter:
>a health problem exists
>the problem is getting worse
explanations
-for observed changes in frequency not due to changes in risk factors >inconsistent interpretation >change in case definition >improved diagnosis >change in reporting >random events
health programs may be aimed at
- increasing vaccination levels
- reducing smoking
- increasing physical activity
- decreasing obesity
- increasing screening
vaccine preventalbe disease
-monitor
-may say program is not reaching specific at risk populations
-barriers exist?
>address them and alter program
field investigation
- public health department
- vary in extent
- vary with regard to objective
- learn about natural history, risk factors
analytic studies
-evaluating hypotheses generated from surveillence and field investigations >study design >case definition development >calculation of rates >reccomendations based on intrepretation
effectiveness
-does the program produced intended result in the field?
efficiency
-does the program produce intended results with a minimum cost of the time and resources?
team approach multidisciplinary
- local, provincial and federal
- academia, clincial, private
- shared online info and professional meetings
value determined by
- appropriate actions have been taken
- info has been used to make decisons and take action
- relates to level and distribution
- info may be used in the future
policy development
-reccomendation of appropriate interventions
>disease control
>reportable disease regulations
>health care policy
causal insights
- plotting over time can give insights into probable determinants
- if only occurs in summer then search for causal factors
confounding factors
-always a treat in descriptive studies
>analytic epidemiologic studies and better for minimizing the threat of confounding
