Mumps case definition

This document contains the case definitions for Mumps which is nationally notifiable within Australia. This definition should be used to determine whether a case should be notified.

Page last updated: 19 December 2021

Surveillance case definition

Version Summary of changes Last reviewed Implementation date

2.0

Inclusion of a probable case definition
Additional detail to laboratory definitive evidence point 3 criterion and inclusion of a footnote to allow recently vaccinated cased to potentially be considered as confirmed cases
Laboratory suggestive evidence moved and adjusted to form part of the probable case definition
Adjustment to the clinical evidence criteria

September 2021

01 January 2022

1.0 Initial case definition 2004 2004

Australian national notifiable diseases case definitions - Mumps

Reporting

Both confirmed cases and probable cases should be notified.

Confirmed case

A confirmed case requires laboratory definitive evidence.

Laboratory definitive evidence

  1. Isolation of mumps virus*

OR

  1. Detection of mumps virus by nucleic acid testing*

OR

  1. IgG seroconversion or a significant increase in antibody level, such as a fourfold or greater rise in titre to mumps virus EXCEPT if the case has received a mumps-containing vaccine eight days to eight weeks prior to specimen collection. (NOTE: paired sera must be tested in parallel).

*If mumps vaccine has been given in the 25 days prior to illness onset wild-type virus must detected to be classified as a confirmed case. Vaccine-associated mumps illness (genotype A) is not notifiable, but rather should be reported as an adverse event following immunisation

Probable case

A probable case requires either:

Laboratory suggestive evidence AND clinical evidence

OR

Clinical evidence AND epidemiological evidence.

Laboratory suggestive evidence

  1. Detection of mumps-specific IgM antibody, EXCEPT
    • a - If ruled out by more specific mumps IgM serology testing at a jurisdictional public health laboratory

OR

    • b - If the case has received a mumps-containing vaccine eight days to eight weeks before specimen collection.

Clinical evidence

A clinically compatible illness (e.g swelling of the parotid or other salivary glands lasting at least two days, or orchitis) without other apparent cause.

Epidemiological evidence

An epidemiological link is established when there is:

  1. Contact between two people involving a plausible mode of transmission at a time when:
    • a - one of them is likely to be infectious (6-7 days before onset of overt parotitis to 9 days after);

AND

    • b - the other has an illness that starts within approximately 12 to 25 days after this contact;
  1. At least one case in the chain of epidemiologically linked cases (which may involve many cases) is a laboratory confirmed case.

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