An update from OFFLU on High Pathogenicity Avian Influenza in Australia and New Zealand

A report produced by the OFFLU Wildlife Technical Activity and released jointly by the World Organization for Animal Health (WOAH) and the Food and Agriculture Organization of the United Nations (FAO) updates the occurrence of High Pathogenicity Avian Influenza in Australia and New Zealand.  Notably, 17 infected ACAP-listed giant petrels (Macronectes sp.) have been reported from the coast of Australia (overall 231 confirmed cases) on 10 August 2026.

The report’s Executive Summary follows:

“What was long expected, has now come to pass: high pathogenicity avian influenza H5 (HPAI H5) has been detected for the first time in wild birds in Australia in June 2026 and in New Zealand in July 2026.

HPAI H5 has a high burden of disease for poultry and wildlife, as well as a zoonotic risk for humans. Since the emergence of HPAI H5 (specifically, the A/Goose/Guangdong/1/1996 lineage) in Asia in 1996, it has been detected in ever more continental regions. It spread from Europe to North America in 2021, to South America in 2022, and to the Antarctic region (Antarctica and sub-Antarctic islands) in 2023. Since its incursion in the Antarctic region, it spread nearly 6,500 km eastwards in two years, from South Georgia in the South Atlantic Ocean in October 2023 to Heard Island in the southern Indian Ocean in October 2025.

It is likely that HPAI H5 was carried from the Antarctic region to Australia and New Zealand by migratory seabirds. Between 14 June and 31 July 2026, HPAI H5 was detected in 1 Brown Skua (Stercorarius antarcticus) and 17 giant petrels (Macronectes sp.) on the coast of Australia, and 1 Brown Skua on the coast of New Zealand. These species breed in spring in the Antarctic region, here they are known to have been infected by HPAI H5. In the non-breeding period, these species may disperse widely, including northwards to waters off the coasts of Australia and New Zealand. Preliminary phylogenetic analysis shows that the HPAI H5 virus detections in wild birds in Australia are closely related to viruses from Heard Island in the Antarctic region.

HPAI H5 has subsequently spilled over from these seabirds to resident bird species in Australia and New Zealand. In Australia, HPAI H5 has been detected in 34 Greater Crested Terns (Thalasseus bergii) as of 31 July 2026. The Greater Crested Tern is a largely resident species in Australia and occurs widely along the coast and offshore islands, a habitat shared with many other seabird species. In New Zealand, HPAI H5 has been detected in one Swamp Harrier (Circus approximans) as of 31 July 2026. The Swamp Harrier is a resident species in New Zealand. In winter it feeds largely on carrion, which is a likely source of infection in avian scavengers.

Based on the sequence of events in other continents, HPAI H5 is likely to spread among wild birds and mammals in Australia and New Zealand. The main wildlife groups at risk are seabirds (e.g. gannets, terns and albatrosses), other waterbirds (e.g. ducks, swans and grebes), pinnipeds (e.g. seals and sea lions), and predatory and scavenging birds and mammals (e.g. raptors, corvids, Dingoes (Canis familiaris dingo) and quolls). From Australia and New Zealand, HPAI H5 may spread to other parts of Oceania (Melanesia, Micronesia, Polynesia), most likely via medium- or long-distance movements of wild birds.

The potential conservation impact from HPAI-H5-associated wildlife morbidity and mortality in Oceania is enormous. Oceania contains many geographically restricted and threatened wildlife populations. For susceptible species, particularly colony-nesting seabirds and pinnipeds, additional mortality associated with HPAI H5 could compound existing pressures on populations.

Although it is not possible to stop the geographical spread of HPAI H5, there are response options to reduce its spread and impact on wildlife, as well as the risk of such HPAI panzootics occurring in the future. Short-term response options include expanding and improving avian influenza surveillance in wildlife, coordination of surveillance across Oceania, removal of infected wildlife carcasses, management of human activities in regions with affected wildlife, vaccination of threatened wildlife species, and avoidance of activities that harm or disturb wildlife and their habitats. In case of HPAI H5 spillover to poultry (which has so far not been reported in Australia or New Zealand), short-term response options include rapidly controlling outbreaks and limiting concurrent infections in poultry populations, thereby reducing opportunities for continued viral evolution and recurrent spillback into local wildlife. Medium- and long-term response options include long-term monitoring of impacted wildlife populations, increasing resilience of susceptible wildlife populations (including by actively reducing other threats and promoting actions to enable recovery of populations) and reducing the risk of HPAI emergence and spillover from poultry in the future.

Post scriptum (10 August 2026): Following the drafting of this statement, further cases of HPAI H5 have been detected in wild birds in Australia. These include: a mass mortality event in Greater Crested Terns in South Australia involving over 80 sick or dead individuals. Several detections have been made in Silver Gulls (Chroicocephalus novaehollandiae), a widespread resident species in Australia and New Zealand that occurs both on the coast and inland, including wetland habitats and urban environments. A single detection has been made in an Australian Magpie (Gymnorhina tibicen), a widespread resident species in Australia, member of the Artamidae family and is omnivorous. As of 10 August 2026, there have been 231 confirmed detections of H5 HPAI in wild birds in Australia (10 in Western Australia, 163 in South Australia, 53 in Victoria, 4 in New South Wales and 1 in Queensland), while there the number of confirmed detections in New Zealand has remained at two.”

Read earlier reports in HPAI in ACAP Latest News for mainland Australia and New Zealand. Since publication of the OFFLU report, HPAI has been reported from Tasmania (10 cases, including a Brown Skua).

With thanks to David Duffy.

Reference:

OFFLU Wildlife Technical Activity 2026.  Incursion of High Pathogenicity Avian Influenza H5 into Australia and New Zealand, with potential to impact wildlife populations and to spread further in Oceania.  OFFLU Wildlife Statement IV.   WOAH/FAO.  33 pp.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 19 August 2026