What is a sporadic in epidemiology?

epidemiology is ofcourse, the study of disease and ewpidemiologists often study the diseases in a certain location, area, of community.

There are three main category of epidemology;Endemic is a disease that is constantly present to a greater or lesser degree in people of a certain class or in people living in a particular location;...

Sporadic CJD represents at least 85% of all cases. Sporadic cases have no identifiable source of infection.

Used for surveillance systems in tracking disease trends ie incidence, prevalence, case-fatality ratios etc