Lecture 10 - Investigating Epidemics Flashcards
Define epidemic.
Occurrence of a disease in a defined population in excess of normal expectancy
What is the difference between epidemic and endemic?
Epidemic is higher than normal.
Endemic is simply the normal/typical disease rate of a population.
Define incidence rate.
Number of new cases/total population over a period of time
Define prevalence rate.
Number of cases/total population
Define attack rate.
Number ill/number exposed
What is epidemiology?
Study of disease in a population: cause, spread, control
How are outbreaks detected?
Surveillance organisations e.g. National Control Centre
Hospitals
Lab data
Informal sources e.g. media
What is a common point source outbreak?
Many people are exposed to a common source, so all get infected at approximately simultaneously. Then relatively quick resolution. E.g. food-source
What is a common persistent source outbreak?
Same as common point source outbreak however slower resolution because it is more difficult to contain. E.g. water-source
What is a common intermittent source?
Sporadic exposure to causative agent. E.g. seasonal fu
What is a propagated outbreak?
Each case has the ability to infect and cause new cases, keeps outbreak going.
State the steps in the ‘identify’ component of the basic principles of epidemic investigation.
Identify whether it is actually an epidemic.
Confirm the diagnosis.
Construct a working case definition
What are some important parts of ‘interpret’ component?
Interpret epidemiology in terms of time (curve of incidence across time), place (informs spread), and person (identifies greatest risk factors).
Establish an explanatory hypothesis.
What is the ultimate goal of epidemic investigations?
Propose and implement control measures.
