Smallpox case definition

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

Page last updated: 12 March 2004

Australian national notifiable diseases case definitions - Smallpox


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 variola virus, confirmed at the Victorian Infectious Diseases Reference Laboratory


2. Detection of variola virus by nucleic acid testing, confirmed at the Victorian Infectious Diseases Reference Laboratory.

Probable case

A probable case requires either:

1. Clinical evidence AND Laboratory suggestive evidence


2. Clinical evidence

AND epidemiological evidence.

Laboratory suggestive evidence

1. Detection of a poxvirus resembling variola virus by electron microscopy

2. Isolation of variola virus pending confirmation

3. Detection of variola virus by nucleic acid testing pending confirmation

Clinical evidence

Credible clinical smallpox as judged by an expert physician.

Epidemiological evidence

An epidemiological link to a confirmed case.


The Guidelines for Smallpox Outbreak, Preparedness, Response and Management include separate case definitions for smallpox surveillance both preceding and during an outbreak. The Guidelines define confirmed, probable, suspected and possible cases for the purposes of public health response. The definitions are at some variance with the case definitions for reporting to the National Notifiable Diseases Surveillance System. Suspected cases and possible cases should also be reported to the State/Territory health department.

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