Epidemic
Epidemic
epidemiology, an epidemic (επί (epi)- meaning "upon or above" and δήμος (demos)- meaning "people"), occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience. Epidemiologists often consider the term outbreak to be synonymous to epidemic, but the general public typically perceives outbreaks to be more local and less serious than epidemics
An epidemic may be restricted to one location, however if it spreads to other countries or continents and affects a substantial number of people, it may be termed a pandemic. The declaration of an epidemic usually requires a good understanding of a baseline rate of incidence; epidemics for certain diseases, such as influenza, are defined as reaching some defined increase in incidence above this baseline.A few cases of a very rare disease may be classified as an epidemic, while many cases of a common disease (such as the common cold) would not.
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