Hepatitis A case definition

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

Page last updated: 20 December 2012

(Effective 1 January 2013)

Reporting

Both confirmed cases and probable cases should be notified.

Confirmed case

A confirmed case requires either laboratory definitive evidence OR laboratory suggestive evidence AND clinical evidence OR laboratory suggestive evidence AND epidemiological evidence

Probable case

A probable case requires clinical evidence AND epidemiological evidence.

Laboratory definitive evidence

Detection of hepatitis A virus by nucleic acid testing.

Laboratory suggestive evidence

Detection of hepatitis A-specific IgM, in the absence of recent vaccination.

Clinical evidence

Child less than 5 years of age

OR

Acute illness with discrete onset of at least two of the following signs and symptoms: fever; malaise; abdominal discomfort; loss of appetite; nausea

AND

Jaundice or dark urine or abnormal liver function tests that reflect viral hepatitis.

Epidemiological evidence

Contact between two people involving a plausible mode of transmission at a time when:

a. one of them is likely to be infectious (from two weeks before the onset of jaundice to a week after onset of jaundice)

AND

b. the other has an illness that started within 15 to 50 (average 28–30) days after this contact

AND

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


Hepatitis A changes

Confirmed case

Added 'either' and 'OR Laboratory suggestive evidence AND clinical evidence OR laboratory suggestive evidence AND epidemiological evidence.'

Laboratory definitive evidence

Removed 'Detection of anti-hepatitis A IgM, in the absence of recent vaccination.'

Laboratory definitive evidence

Added 'Detection of hepatitis A virus by nucleic acid testing.'

Laboratory suggestive evidence

Added 'Detection of hepatitis A-specific IgM, in the absence of recent vaccination.'

Clinical evidence

Changed to Child less than 5 years of age OR Acute illness with discrete onset of at least two of the following signs and symptoms: fever; malaise; abdominal discomfort; loss of appetite; nausea AND jaundice or dark urine or abnormal liver function tests that reflect viral hepatitis.

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