Epidemic Disease Occurrence Flashcards
Baseline/Endemic Disease
amount of a particular disease that is usually present in a community (expected level of disease)
Sporadic
refers to a disease that occurs infrequently and irregularly
Endemic
refers to the constant/usualy prevalence of a disease or infectious agent in a population within a geographic area
hyperendemic
refers to persistent high levels of disease occurrence
Epidemic
refers to a increase, often sudden in the number of cases of a disease above what is normally expected in that population in that area
outbreaks
- same definition of epidemic but used for a more limited geographic area
Cluster
refers to an aggregation of cases, grouped in place and time that are suspected to be greater than the number expected even though the number expected may not be known
Pandemic
refers to an epidemic that has spread over several countries or continents, usually affecting a large number of people.
What must happen for an epidemic to occur?
- more virulence
- intro of the agent into a new area
- enhanced mode of transmission
- change in host susceptibility
increase host exposure
What are the 4 main epidemic patterns .
- common source
- propagated
- mixed
- other
What are the 3 types of common source epidemic patterns
- point source
- continuous
- intermittent
What ia common source epidemic pattern?
a group of persons are all exposed to an infectious agent or a toxin from the same source
Point source epidemic pattern
- relatively brief period
- within one incubation period
- steep upslope and gradual downslope
- leukemia after hiroshima
Continuous and Intermittent-Source
range of exposures and range incubation period tend to flatten and widen the peaks of the epidemic curve
Propagated Source
transmission from one person to another
- person to person
- vehicle borne
- vector borne
- more than one incubation period
- usually wanes after generations
