Rubella case definition

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

Communicable Diseases Surveillance

Australian national notifiable diseases case definitions - Rubella

Reporting

Both confirmed cases AND probable cases should be notified.

Confirmed case

A confirmed case requires Laboratory definitive evidence only.

Laboratory definitive evidence

1. Isolation of rubella virus

2. Detection of rubella virus by nucleic acid testing

3. IgG seroconversion or a significant increase in antibody level or a fourfold or greater rise in titre to rubella virus in the absence of recent rubella vaccination. The results must be established by the testing of paired sera in parallel.

4. Detection of rubella-specific IgM, in the absence of recent rubella vaccination. (Note that in pregnant women, the result needs to be confirmed in a reference laboratory.)

Probable case

A probable case requires:

1. clinical evidence

AND

2. Laboratory suggestive evidence OR epidemiological evidence.

Laboratory suggestive evidence

In a pregnant patient, detection of rubella-specific IgM that has not been confirmed in a reference laboratory, in the absence of recent rubella vaccination.

Clinical evidence

1. A generalised maculopapular rash

AND

2. fever

AND

3. arthralgia/arthritis OR lymphadenopathy OR conjunctivitis.

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 (about one week before to at least four days after appearance of rash)
AND
b) the other has an illness which starts within 14 and 23 days after this contact

AND

2. At least one case in the chain of epidemiologically linked cases (which may involve many cases) is laboratory confirmed.