Introduction Flashcards
Epidemiology
Study of distribution and determinants of health related conditions in human populations and the application of this method to the control of health problems.
Considers measuring who has the disease and who has exposure.
Benefits of epidemiology
Description of health status of populations explanation of the aetiology of disease
Predict the likely occurrence of disease/ health and identify distribution in the population
Control occurrence of disease
Use of epidemiology
Can be used to describe both healthy and unhealthy populations- described demographically
Track trends
Establish risk factors
Determines the health of a community
Epidemiology and research
Monitors the health status of a population and searches for risk factors
After a hypothesis is developed, provide descriptive analysis of a problem. Conduct a study to test hypothesis.
Steps used to construct epidemiological research
Determine primary agent Understand causation Determine characteristics of agent Determine mode of transmission Determine contributing factors Assess geographic patterns Define natural history Determine control measures Determine prevention measures Planning health services Determine hypothesis
Epidemic
A disease or condition that affects a greater than expected number of individuals at the same time
Normal occurrence of disease in a pop is known as endemic level.
Epidemic threshold is the upper end of normal range of disease occurrence for a specific population, time frame and location
A pandemic is a geographically widespread epidemic
Stages of clinical disease
Nonclinical : preclinical where signs and symptoms are not yet present, subclinical where symptoms will not become apparent
Recovery Morbidity Disability Mortality Carrier state
Most diseases not identified until in clinical stage, must take note of stage of disease
Epidemiological triangle
Composed of:
Agent- what causes the disease
Host- personal characteristics of those affected by the disease
Environment- external factors that cause or allow disease to be spread
Time ties into triangle elements, crucial to understanding disease transmission
Agent component of the triangle
Agents of infectious diseases are microbes: viruses and bacteria
Agents for non infevtuous disease are risk factors such a as smoking, high bp, and exposure to chemicals or radiations
Host component of triangle
Organisms that are exposed to and Harbour a disease
Can be the organism who gets sick, an organism that transmits an infection but may or may not get sick.
Different hosts ah have different reactions to the same agent.
Host characteristics may affect disease susceptibility:
Age
Gender
Race
Occupation
Immune status
Behaviours
Environment component of triangle
External conditions that cause/ allow disease transmission
Some disease live best in dirty water
Others survive in human blood
Others thrive in warm temp but are killed by high heat
Environmental characteristics shown to promote disease include
Weather
Population density
Geography
Seasonality
Time - centre of triangle
Incubation persons- time between infection of host and symptoms appear
Called latency period for chronic disease. Can be hours, days, weeks.
Time amy also describe duration of disease or amount of time a person is sick before death or recovery occurs.
Epidemiology mission
To break the triangle by understanding cause of disease, groups likely to get the disease and geographical factors conductive of the spread
Breaking the triangle- avoid exposure or immunise against the agent
Address the environmental issue by isolating people with certain disease
Control risk factors for chronic disease
Disease occurrence- descriptive epidemiology of person
The field of medicine deals with one person at a time while epidemiology deals with groups
Who gets the condition?
- how old
- where do they live
- where do they work?
- where were they born
- what sort of people do not get the disease?
- how many cases per 100,000
Does this rate differ between
- men and women
- young and old
- rich and poor
- black and white
- Heterosexual and homosexual
- migrants and locally born
- different occupations
- married or not
Disease occurrence- descriptive epidemiology of place
Where does this disease happen? Is it more common in some place? Does the rate differ between: Countries States Rural and urban Suburbs Communities Households
