count of cases in an epidemic incident epidemic case count Incident case counts are measured according to regular intervals, typically day or week. A count of cases in an epidemic that is about a proper part of the temporal interval occupied by the epidemic. A count of cases in an epidemic that spans a shorter interval, such as a particular day or a week. The count is also nearly always geographically localized, for example, the case count for the state of Pennsylvania or the case count for Waukesha County, Wisconsin. William R. Hogan incident case count