Dengue virus case definition

This document contains the case definitions for Dengue virus 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 laboratory definitive evidence AND clinical evidence.

Laboratory definitive evidence

Isolation of dengue virus

OR

Detection of dengue virus by nucleic acid testing

OR

Detection of dengue non-structural protein 1 (NS1) antigen in blood

OR

IgG seroconversion or a significant increase in antibody level or a fourfold or greater rise in titre to dengue virus, proven by neutralisation or another specific test

OR

Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray Valley encephalitis, West Nile virus /Kunjin, or Japanese encephalitis viruses

Confirmation of the laboratory result by a second arbovirus reference laboratory is required if the infection was locally acquired and occurred in an area of Australia without known local transmission of dengue fever since 1990 (i.e. anywhere outside north Queensland).

Clinical evidence

A clinically compatible illness (eg fever, headache, arthralgia, myalgia, rash, nausea, and vomiting, with possible progression to severe plasma leakage, severe haemorrhage, or severe organ impairment – CNS, liver, heart or other).

Probable case

A probable case requires laboratory suggestive evidence AND clinical evidence AND epidemiological evidence

Laboratory suggestive evidence

Detection of dengue virus-specific IgM in blood.

Clinical evidence

As for a confirmed case

Epidemiological evidence

A plausible explanation, e.g. travel to a country with known dengue activity OR exposure in Australia where local transmission has been documented within the previous month.


Dengue changes

A probable case category was added.

IgM in blood was changed from definitive to suggestive evidence requiring clinical evidence and epidemiological evidence to become a probable case. This is more consistent with the PHLN case definition and resolves the issue of false positive serum IgM 'locally acquired' cases in Queensland, both in north Queensland when there is no known outbreak and in other areas of Queensland where Aedes aegypti is present.

New criterion added under definitive evidence 'Detection of dengue non-structural protein 1 (NS1) antigen in blood' point 3.

Point 4 under laboratory definitive evidence has been re-worded to 'IgG seroconversion or a significant increase in antibody level or a fourfold or greater rise in titre to dengue virus, proven by neutralisation or another specific test.'

Point 5 under laboratory definitive evidence has been re-worded to 'Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray Valley encephalitis, West Nile /Kunjin, or Japanese encephalitis viruses'

Note requiring second reference laboratory testing in area ‘without known previous local transmission’ amended to make clear that this relates to transmission since 1990.

Clinical evidence amended to be consistent with the new WHO classification (p11). Who publications 2009/9789241547871_eng.pdf.

Epidemiological evidence criterion added: 'A plausible explanation, e.g. travel to a country with known dengue activity OR exposure in Australia where local transmission has been documented within the previous month.'

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