Confirmed Case
Clinical illness1 and laboratory confirmation of infection in the absence of recent immunization with mumps-containing vaccine (i.e., within the previous 28 days):
- Isolation of mumps virus from an appropriate clinical specimen OR
- Detection of mumps virus RNA OR
- Significant (e.g. fourfold or greater) rise or seroconversion in serum mumps IgG titre by any standard serologic assay between acute and convalescent sera OR
- Positive serologic test for IgM antibody2 in a person who is epidemiologically linked to a laboratory-confirmed case or has recently travelled to an area of known mumps activity OR
- Clinical illness1 in a person with an epidemiologic link to a laboratory-confirmed case
Clinical / Probable Case
Mumps-compatible illness in the absence of a laboratory confirmation of infection and not epidemiologically linked to a laboratory-confirmed case.
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1Clinical illness is characterized by acute onset of unilateral or bilateral tender, self-limited swelling of the parotid or other salivary gland, or orchitis lasting > 2 days, and without other evident cause.
2IgM serology has the potential for false positive and false negative findings. If the clinical presentation is inconsistent with a diagnosis of mumps or in the absence of recent travel/exposure history, IgM result must be confirmed by the other listed confirmatory methods. In a mumps case that had been previously immunized, the IgM class antibody response may not be detectable.