Notification of avian influenza and Vibrio parahaemolyticus infection

What is the issue?

The Public Health and Wellbeing Act 2008 requires that prescribed conditions and micro-organisms are notified to the Department of Health. This law exists to monitor, prevent and control the occurrence of infectious diseases and other specified conditions to protect the Victorian community from further illness.

From 1 April 2025, avian influenza will become an urgent notifiable condition and Vibrio parahaemolyticus infection will become a routine notifiable condition for both medical practitioners and pathology services in Victoria.

Making these conditions notifiable enables public health response actions to be initiated more promptly and facilitates the collection of more comprehensive and accurate surveillance data.

Avian influenza, commonly referred to as 'bird flu', is a contagious infection of birds, caused by multiple avian influenza viruses. Wild birds are considered the natural host for these viruses. Sometimes these viruses spill over from wild birds into domestic bird populations causing disease. Several outbreaks have previously occurred in Australia among commercial flocks of birds. In May 2024, Australia reported its first human case of avian influenza H5N1 in a returned overseas traveller.

Vibrio parahaemolyticus is a bacterium found in marine waters that most commonly causes acute gastroenteritis with watery diarrhoea, abdominal cramps, nausea, vomiting, fever and headache. Illness is primarily associated with consumption of raw or undercooked seafood, particularly oysters and other shellfish. In Australia, several multi-jurisdictional outbreaks linked to locally grown oysters have occurred over the past ten years, with significant human health, economic and international trade impact. Less commonly Vibrio parahaemolyticus can also cause wound infection when sea water contaminates an open wound.

Who is at risk?

Most people are not at risk of avian influenza, as the viruses do not spread easily from birds to people. People who have close or prolonged unprotected contact with infected birds or animals or their contaminated environments are at highest risk of infection.

Although limited human-to-human transmission of avian influenza viruses may have occurred in some instances, sustained human-to-human transmission has not been identified to date.

People cannot be infected with avian influenza through eating fully cooked poultry or eggs, even in areas with an outbreak.

Vibrio parahaemolyticus infection can infect individuals of any age. Risks factors for developing severe disease include underlying chronic illness, being immunocompromised, consumption of antibiotics and medications that reduce stomach acid levels.

Vibrio parahaemolyticus does not usually spread from person to person, however, person-to-person transmission is possible if there is poor personal hygiene.

Diagnosis

Diagnosis of avian influenza is confirmed using polymerase chain reaction (PCR) for avian influenza viruses, on nasopharyngeal and throat swabs. As sample collection may induce coughing, where avian influenza is suspected swabs should be collected in a negative pressure room if available and using appropriate personal protective equipment (PPE).

Not everyone with symptoms of influenza needs to be tested for or notified as having suspected avian influenza.

A suspected case of avian influenza requires both clinical evidence and epidemiological evidence. Epidemiological evidence may include:

• close contact with a probable or confirmed human avian influenza case
• exposure to birds, bird carcasses, or to environments contaminated by bird faeces, in an area with suspected or confirmed avian influenza infections in birds or other animals
• consumption of raw or undercooked poultry products from an area with suspected or confirmed avian influenza infections in birds
• close contact with a confirmed avian influenza infected animal other than birds (for example, cat or pig)
• handling samples suspected of containing avian influenza virus in a laboratory or other setting.

For more information refer to the Communicable Diseases Network Australia Surveillance Case Definition – Avian influenza.

Diagnosis of Vibrio parahaemolyticus infection relies on laboratory detection of Vibrio parahaemolyticus by nucleic acid testing or isolation of the bacterium from an appropriate clinical specimen. For more information refer to the Communicable Diseases Network Australia Surveillance Case Definition.

Confirmed cases of Vibrio parahaemolyticus infection are designated based only on definitive laboratory evidence and are therefore required to be notified by pathology services.

Recommendations

For medical practitioners

• From 1 April 2025, medical practitioners must notify all patients with suspected or confirmed avian influenza to the Department of Health immediately (as soon as practicable and within 24 hours) upon diagnosis by telephone on 1300 651 160 (24/7). Notifying medical practitioners will be connected to the appropriate Local Public Health Unit.
• Seek laboratory confirmation urgently for all suspected cases of avian influenza. All suspected cases should be discussed with the relevant Local Public Health Unit who can provide advice on testing and coordinate with the laboratory.
• All samples should be sent for urgent testing at the Victorian Infectious Diseases Reference Laboratory (VIDRL). Record relevant clinical details, suspected diagnosis and risk factors on the request form.
• Consider the need for contact management of patients with avian influenza. This may include post-exposure prophylaxis in eligible high-risk contacts. For further advice, refer to an infectious disease specialist or contact your Local Public Health Unit (after hours contact via 1300 651 160).
• Further information about the notification process and the Public Health and Wellbeing legislation are available on the Notifiable infectious diseases, conditions and micro-organisms page.

For pathology services

• From 1 April 2025, pathology services must notify any isolation or detection of avian influenza (subtype of Influenza A) to the Department of Health immediately (as soon as practicable and within 24 hours) upon diagnosis by telephone on 1300 651 160 (24/7). Notifying pathology services will be connected to the appropriate Local Public Health Unit. Pathology services must also follow up with written notifications within 5 working days.
• From 1 April 2025, pathology services must provide written notification of any isolation or detection of Vibrio parahaemolyticus within five working days to the Department of Health by electronic laboratory report (ELR) or by faxing the laboratory report to 1300 651 170.

More information

• Notifiable infectious diseases, conditions and micro-organisms
• Avian influenza - Department of Health
• Avian influenza – Communicable Diseases Network Australia Surveillance Case Definition
• Vibrio parahaemolyticus infection – Department of Health
• Vibrio parahaemolyticus infection – Communicable Diseases Network Australia Surveillance Case Definition

Contacts

For more information, please contact the Department of Health on 1300 651 160 (24/7).