(1) Denoting a temporal pattern of disease occurrence in an animal or human population in which the disease occurs only rarely and without regularity.endemic, epidemic, enzootic, epizootic (2) In the genetic context, sporadic denotes a singleton or sport. Several quite different and disparate phenomena are covered by this term, including a new mutation; occult nonpaternity; the chance outcome for a recessive trait in two carrier parents with a small family; extreme variability in the expression of a gene; an environmental phenocopy; a multilocal genocopy, etc. No useful properties can be predicated of all members of this class; and the term is notionally useless. (3) Occurring irregularly, haphazardly. [G. sporadikos, scattered]