Final answer:
An epidemic is the term used to describe when new cases of a disease occur in a human population and substantially exceed what is unexpected, based on recent experience. It is an illness with a higher-than-expected incidence in a given period within a given population.
Step-by-step explanation:
The term used to describe when new cases of a disease occur in a human population and substantially exceed what is unexpected, based on recent experience, is epidemic. An epidemic is an illness with a higher-than-expected incidence in a given period within a given population. For example, influenza can become epidemic if there is a larger number of cases in a particular region during a particular season.