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1990 Case Definition

Clinical Description

An illness with acute onset of unilateral or bilateral tender, self-limited swelling of the parotid or other salivary gland, lasting greater than or equal to 2 days, and without other apparent cause (as reported by a health professional)

Laboratory Criteria for Diagnosis

  • Isolation of mumps virus from clinical specimen, OR
  • Significant rise in mumps antibody level by any standard serologic assay, OR
  • Positive serologic test for mumps immunoglobulin M (IgM) antibody

Case Classification


Meets the clinical case definition, has no or noncontributory serologic or virologic testing, and is not epidemiologically linked to a confirmed or probable case


A case that is laboratory confirmed or that meets the clinical case definition and is epidemiologically linked to a confirmed or probable case. A laboratory-confirmed case does not need to meet the clinical case definition.


Two probable cases that are epidemiologically linked would be considered confirmed, even in the absence of laboratory confirmation.