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Pronunciation: spo-rad'ik


  1. Denoting a temporal pattern of disease occurrence in an animal or human population in which the disease occurs only rarely and without regularity.
  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.

See: endemic, epidemic, enzootic, epizootic

[G. sporadikos, scattered]

Further information

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© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.