Intro epi Flashcards
Epidemiology
Study of how disease distributed in populations, and factors that influence or determine this distribution.
Objectives of epidemiology
- Determine burden of disease in a population
- Identify etiology/cause of dz and relevant risk factors
- Study natural history and prognosis of dz
- Eval preventative and therapeutic measures and modes of health care delivery
- Provide foundation for developing public policy regarding dz prevention and health promotion
Primary prevention
Preventing initial development of disease.
IE: vaccination, reducing exposure to risk factor
Secondary prevention
Early detection of existing disease to reduce severity and complications.
IE: Screening for disease
Tertiary prevention
Reducing impact of the disease.
IE: Treatment, rehab
Objectives of epidemiology
- Determine burden of disease in a population
- Identify the etiology or cause of dz and the relevant risk factors
- To study natural history and prognosis of dz
- To evaluate preventative and therapeutic measures and modes of health care delivery
- Provide foundation for developing public policy regarding dz prevention and health promotion
The practice of medicine is dependent on
Population data
Pyramid of increasing evidence strength
From top of pyramid:
- Systematic review/meta-analysis
- Randomized Controlled Trial
- Cohort
- Case Control
- Cross Sectional
- Case reports and series
- Ideas, opinions, editorials
- Animal Research
- Invitro ‘test tube’ research
Epidemiologic triad of desase
Host-vector
Vector-Agent and Environment
Host factors of dz transmission
Age
Sex
Breed
Immune status
Agent factors of dz transmission
Biologic -bacteria Chemical -poison Physical -trauma Nutritional -lack -excess
Environmental factors of dz transmission
Temperature Humidity Altitude Housing Water Food Air Pollution
Modes of disease transmission
Direct: animal-animal/person-person Indirect -water -air -vector
Carrier status
- Harbor disease organism but not infected judged by serology (no antibody response) or clinical illness
- Can still infect others
- Status as carrier can be limited or long duration
Endemic
AKA enzootic
Disease agent normally present in regular frequency
Epidemic
AKA epizootic
Increase in disease from what’s normal
Pandemic
World-wide epidemic
Characteristics of disease outbreaks
- Common vehicle exposure: Single vs multiple exposure
- Periodic contamination
- Continuous contamination
Amount of disease in a population depends on
balance between susceptible (non-immune) and non-susceptible (immune) people, animals.
Herd Immunity
Resistance of a group to attack by disease to which a large proportion of members are immune
Herd Immunity assumes
Random mixing
Herd immunity operates optimally when
populations are constantly mixing together
Reproduction ration
The amount of cases one diseased individual causes.
Incubation period
Interval from receipt of infection to time of clinical illness
