Highly pathogenic avian influenza

[Shore birds - Image - Guy Weerasinghe]

Page updated 6 February 2025

Latest Updates

On 8 February 2025, Agriculture Victoria confirmed the presence of HPAI H7N8 at a poultry farm in northern Victoria. The property has been placed under quarantine and a declared area is in place in the eastern two-thirds of the Strathbogie Shire to prevent movements that could spread the virus. Please see Agriculture Victoria for more information: https://agriculture.vic.gov.au/biosecurity/animal-diseases/poultry-diseases/avian-influenza-bird-flu

Diagnostic testing performed by Australian Centre for Disease Preparedness at Geelong confirmed high pathogenicity H7N8, which is different to the strain that impacted Victorian poultry farms during 2024. Although the 2024 New South Wales/Australian Capital Territory outbreak was also an H7N8 virus, the current laboratory has advised that the current Victorian outbreak is a different virus.

Any suspicion of an emergency animal disease (EAD) should be immediately reported to the 24-hour EAD Hotline on 1800 675 888.

For information on current emergency animal disease (EAD) outbreaks in Australia along with an overview of emerging risks, visit the Outbreak website: https://www.outbreak.gov.au/

Recent past events

On 3 February 2025, Australia officially self-declared freedom from high pathogenicity avian influenza (HPAI) H7 to the World Organisation for Animal Health, with effect from 23 January 2025. In 2024, a coordinated response was undertaken to address three strains of HPAI H7. A total of 16 infected premises were identified, including 8 in Victoria, 6 in New South Wales, and 2 in the Australian Capital Territory. Through comprehensive eradication efforts, HPAI H7 has been eliminated from Victoria, NSW, and the ACT, with no new detections reported in Australia since 12 July 2024.

Background

Avian influenza is a global viral disease of birds and there are many strains of the virus that cause infections of differing severity, and all bird species are considered vulnerable to avian influenza. High pathogenicity avian influenza (HPAI) viruses are associated with severe disease and high mortality in poultry. HPAI H5N1 clade 2.3.4.4b is the predominant strain causing recent outbreaks globally.

Avian influenza viruses (both low pathogenicity and high pathogenicity strains) have also been known to infect other animal species overseas. Spill over infections of the H5N1 strain of HPAI virus in non-avian animal species such as pigs, tigers, leopards and domestic cats have been reported in some countries.

The 2024 outbreaks of HPAI H7 in New South Wales, the Australian Capital Territory, and Victoria have now been successfully resolved. However, ongoing outbreaks of H5N1 globally have increased Australia’s level of risk for incursions of HPAI viruses of global concern. Migratory birds returning to Australian shores annually between September and November may introduce HPAI viruses.

Avian influenza is a national notifiable emergency animal disease (EAD) and any unusual bird deaths must be reported to the Emergency Animal Disease Hotline on 1800 675 888. This number will connect you with your state or territory’s department of primary industries or agriculture.

Zoonotic disease:

Avian influenza is a zoonotic disease and is potentially fatal to humans. The disease can be passed from birds to humans who are in close contact with poultry or other birds. In Australia, there is minimal risk of people being affected by avian influenza viruses through normal contact with healthy birds, however it is important to always practice good personal hygiene when handling birds.

For more information about avian influenza in humans, visit the Department of Health and Aged Care website: https://www.health.gov.au/diseases/avian-influenza-in-humans-bird-flu

Good biosecurity practices are the key to preventing the spread of avian influenza in poultry species and are critical in combating any incursion. The following information about bird biosecurity is a valuable resource to make clients aware of: https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/protect-animal-plant/bird-owners

Key information about the clinical signs:

The clinical signs of avian influenza in birds are variable and depend on a range of factors including the virulence of the virus, the species and age of the birds infected, the presence of concurrent diseases, and the environment. In severe forms, such as H5N1 infection, the disease appears suddenly and birds die quickly.

HPAI should be considered as a differential diagnosis in the following scenarios for wild birds:

Small groups or clusters (5 or more) of sick or dead wild birds of any species.
Individual or <5 sick or dead wild birds:
- seabirds, waterbirds, shorebirds or birds of prey
- any other bird species with signs of avian influenza infection as outlined below.

Infected live birds may show a wide range of clinical signs, including:

Neurological signs (ataxia, paralysis, seizures, tremors, abnormal posture)
Respiratory signs (conjunctivitis, increased nasal secretions, oedema of the head, dyspnoea)
Gastrointestinal signs (diarrhoea)
Sudden death

Some species may be asymptomatic or show only very mild clinical signs. In some cases, birds may die suddenly without displaying any clinical signs.

High Pathogenicity Avian Influenza and Wild Birds - Advice for veterinarians and animal health professionals: https://wildlifehealthaustralia.com.au/Portals/0/Incidents/HPAI_Advice_for_veterinarians_and_animal_health_professionals.pdf

Emergency animal diseases: A field guide for Australian veterinarians https://www.outbreak.gov.au/prepare-respond/identify-pests-diseases/emergency-animal-diseases-field-guide

[Eastern Curlews - Image - Guy Weerasinghe]

Resources:

Australian Centre for Disease Control:

The Department of Agriculture, Fisheries and Forestry (DAFF): https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/animal/avian-influenza

CSIRO https://www.csiro.au/en/research/animals/veterinary/tracking-avian-influenza

Queensland Government https://www.business.qld.gov.au/industries/farms-fishing-forestry/agriculture/biosecurity/animals/diseases/guide/avian-influenza#

New South Wales Government https://www.dpi.nsw.gov.au/animals-and-livestock/poultry-and-birds/health-disease/avian-influenza

Victorian Government https://agriculture.vic.gov.au/biosecurity/animal-diseases/poultry-diseases/avian-influenza-bird-flu

South Australian Government https://pir.sa.gov.au/biosecurity/animal_health/animal_species/poultry/avian_influenza#

Western Australian Government https://www.agric.wa.gov.au/livestock-biosecurity/avian-influenza

Tasmanian Government https://nre.tas.gov.au/biosecurity-tasmania/animal-biosecurity/animal-health/poultry-and-pigeons/avian-influenza

Northern Territory Government https://health.nt.gov.au/public-health-notifiable-diseases/avian-influenza

The Wildlife Health Australia:

WHA video on H5 avian influenza (bird flu) in wildlife - an educational webinar developed for government wildlife managers which includes a general H5 bird flu update

WHA document of H5 bird flu frequently asked questions (FAQs)

WHA Fact Sheet "Avian influenza in wild birds"

Technical Update - Global HPAI in Wildlife has been updated which summarises current global high pathogenicity avian influenza (HPAI) events in wildlife and the risks to Australia

World Organisation for Animal Health (WOAH): https://www.woah.org/en/disease/avian-influenza/

Antarctic HPAI monitoring project: https://scar.org/resources/hpai-monitoring-project/

Western Australian Department of Primary Industries and Regional Development (DPIRD): Avian influenza webinar for Western Australian veterinarians (11 February 2025)