National case definition: Mumps
Date of last revision/review: May 2008
Only confirmed cases of disease should be notified.
Type of surveillance
Routine case-by-case notification to the federal level.
Clinical illness (see Clinical evidence section) and laboratory confirmation of infection in the absence of recent immunization (see Clinical evidence section) with mumps-containing vaccine:
- isolation of mumps virus from an appropriate clinical specimen
- detection of mumps virus RNA
- seroconversion or a significant rise (e.g. fourfold or greater) in mumps IgG titre by any standard serologic assay between acute and convalescent sera
- positive serologic test for mumps IgM antibody (see Laboratory comments section) in a person who is either epidemiologically linked to a laboratory-confirmed case or has recently travelled to an area of known mumps activity
Clinical illness in a person with an epidemiologic link to a laboratory-confirmed case
- in the absence of appropriate laboratory tests
- in the absence of an epidemiologic link to a laboratory-confirmed case.
IgM serology has the potential for false-positive findings. If the clinical presentation is inconsistent with a diagnosis of mumps or in the absence of recent travel/exposure history, IgM results must be confirmed by the other listed confirmatory methods.
Further strain characterization is indicated for epidemiologic, public health and control purposes.
Clinical illness is characterized by acute onset of unilateral or bilateral tender, self-limited swelling of the parotid or other salivary gland, lasting > 2 days, and without other apparent cause.
The most frequent reaction to measles-mumps-rubella (MMR) immunization is malaise and fever (with or without rash) occurring 7-12 days after immunization. Parotitis has occasionally occurred after immunization. However, this should be determined for each case, as these reactions and the time frame can vary (Canadian Immunization Guide, 7th edition).
A laboratory-confirmed case may not exhibit clinical illness, as up to 30% of cases are asymptomatic.
The case definitions for mumps provided in this document are for routine surveillance purposes. Probable case definitions are provided as guidelines to assist with case finding and public health management, and are not for national notification purposes. Readers are referred to the document Laboratory Guidelines for the Diagnosis of Mumps (2007) for further information on the collection, transport, laboratory testing and laboratory test interpretation of specimens suspected of mumps.
Public Health Agency of Canada. Laboratory Guidelines for the Diagnosis of Mumps (PDF format). 2007. Retrieved May 2008 from: http://www.nml-lnm.gc.ca/guide/docs/Mumps_Lab_guide.pdf
Previous case definitions
Canadian Communicable Disease Surveillance System: disease-specific case definitions and surveillance methods. Can Dis Wkly Rep 1991;17(S3).
Case definitions for diseases under national surveillance. CCDR 2000;26(S3).
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