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1996 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

Laboratory Criteria for Diagnosis

  • Isolation of mumps virus from clinical specimen, OR
  • Significant rise between acute- and convalescent-phase titers in serum mumps immunoglobulin G (IgG) antibody level by any standard serologic assay, OR
  • Positive serologic test for mumps immunoglobulin M (IgM) antibody

Case Classification


A case that meets the clinical case definition, has noncontributory or no 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. False-positive IgM results by immunofluorescent antibody assays have been reported.1


  1. Schluter WW, Reef SE, Dykewicz DA, Jennings CE. Pseudo-Outbreak of Mumps--Illinois, 1995 [Abstract]. in: Program and Abstracts of the 30th National Immunization Conference, Washington, DC, April 9-12, 1996