Key Takeaways
- H5N1 is now on every continent. Highly pathogenic avian influenza reached Antarctica in the 2023–24 austral summer and mainland Australia in 2026, meaning the virus has now been detected on all seven continents. Australia stopped counting individual birds on 12 August 2026 and now counts confirmed events: 318 of them as of 26 August, across six jurisdictions after Tasmania joined the list. Three mass mortality events reported on 20 August involved more than 1,000 dead crested terns, and on 23 August a long-nosed fur seal at Beachport became Australia’s first confirmed mammal case. Bird-to-bird spread is established and the country has accepted that the virus can no longer be eradicated from wildlife. WOAH logged outbreaks in 43 countries in poultry and 53 in wild birds in the 2025–26 wave alone.
- 1,507 poultry outbreaks this wave. Between October 2025 and May 2026, WOAH recorded 1,507 HPAI outbreaks in poultry and 7,098 in wild birds. The wave peaked in November 2025, and roughly 2.16 million birds died or were culled in May 2026 alone, the bulk of them in Europe.
- The jump to cattle keeps spreading. H5N1 has infected more than 1,000 US dairy herds across 17 to 19 states since 2024, and in early 2026 a dairy cow in the Netherlands became the first cattle case outside North America.
- 993 human cases, 477 deaths since 2003. The WHO has confirmed 993 human H5N1 cases in 25 countries since 2003, of which 477 were fatal, a case-fatality rate near 48%. Cambodia is the current hotspot and the United States has recorded 71 mostly mild cases since 2024.
- Pandemic risk is rising but not here yet. There is still no sustained human-to-human transmission, and public-health agencies rate the risk to the general public as low. But scientists warn the sheer scale of animal infection gives the virus more chances than ever to adapt.
Bird flu has quietly become one of the largest animal-disease events ever recorded. The strain behind it, a highly pathogenic avian influenza virus known as H5N1, has spread from poultry farms into wild birds, marine mammals, dairy cattle and, in a growing trickle of cases, people. In the 2025–26 season it reached mainland Australia and Antarctica, meaning the virus has now been detected on every continent on Earth.
This is the map we have not drawn before: not a single human outbreak, but an animal-health emergency playing out across dozens of countries at once. The map below shows where H5N1 was reported in the current wave, with the new frontiers it crossed in 2026 marked.
What H5N1 is, and why 2026 is different
H5N1 is a subtype of influenza A that is highly pathogenic in birds, meaning it kills domestic poultry quickly and in large numbers. It has circulated since the late 1990s, but the version driving the current crisis, a lineage called 2.3.4.4b, behaves differently from its predecessors. Instead of flaring up in poultry each winter and fading, it now persists year-round in wild birds, which carry it along migratory flyways to every corner of the planet.
That shift matters because wild birds are impossible to vaccinate, cull or contain. Once the virus established itself in wild populations, it gained a permanent reservoir from which it can spill back into farms, and increasingly into mammals. What was once a seasonal farming problem has become a standing feature of the global environment.
The global footprint: where bird flu is now
The scale of the current wave is hard to overstate. Between October 2025 and May 2026, the World Organisation for Animal Health (WOAH) recorded 1,507 HPAI outbreaks in poultry across 43 countries and a further 7,098 outbreaks in wild birds across 53 countries and territories. The wave peaked in November 2025, and even in the quieter month of May 2026 roughly 2.16 million birds died or were culled, the bulk of them in Europe.
The losses concentrate in a handful of large poultry producers. The United States has lost more than 168 million birds since the outbreak began in 2022, across all 50 states. In the current European season, Poland was the hardest hit with about 9.26 million birds affected on 130 farms, while Germany culled more than a million birds and saw thousands of wild cranes die. France and the Netherlands round out the worst-affected European producers. For historical scale, WOAH counts more than 633 million poultry lost worldwide between 2005 and 2024, with a single-year peak of 146 million in 2022.
The geography of the wave is now shifting with the seasons. Reported poultry outbreaks across Europe have thinned as the northern summer set in, while the active front has moved to the Southern Hemisphere. Australia, which recorded its first cases in June 2026, is now the fastest-moving part of the story, with detections rising from 28 on 30 July to 101 by 5 August and 236 by the evening of 11 August.
That trajectory has not slowed. By 20 August South Australia alone had 177 confirmed cases and three mass mortality events on offshore islands, and Tasmania had become the sixth Australian jurisdiction to report the virus.
On the new event-based count Australia reached 298 confirmed events by 23 August and 318 by 26 August 2026. South Australia carries 194 of them, Victoria 94, New South Wales 11, Western Australia 10, Tasmania eight and Queensland one.
There is still no detection in poultry or the wider agriculture system anywhere in Australia, and the risk to human health is still rated low.
New Zealand, which followed in July 2026, has stayed quiet by comparison: three detections in total, the most recent on 21 August, and no sign of mass wildlife mortality.
The new frontiers of 2026
Three developments in 2026 pushed the virus into genuinely new territory, and they are the milestones marked on the map above.
Australia recorded its first mainland H5N1. Having kept the 2.3.4.4b lineage out for years, Australia confirmed the virus in wild seabirds in Western Australia in June 2026. By 8pm AEST on 11 August 2026 the federal agriculture department counted 236 confirmed detections in wild birds, up from 101 on 5 August, and still none in poultry or the wider agriculture industry.
The tally is climbing daily. On 3 August it stood at 78 across five jurisdictions: 58 in South Australia, 10 in Western Australia, seven in Victoria, two in New South Wales and one in Queensland. Two days later it had passed 100.
It has roughly doubled twice since. The 11 August count of 236 breaks down as 163 in South Australia, 58 in Victoria, 10 in Western Australia, four in New South Wales and one in Queensland.
The raw tally has now been retired. From 12 August 2026 the department stopped counting individual birds and switched to counting confirmed events, where one event may involve a single bird or hundreds.
The reason was arithmetic: hotline reports of sick or dead birds had run roughly thirteen times ahead of completed investigations. On the new basis Australia had 219 confirmed events in wild birds as of 4pm AEST on 14 August 2026, a figure that folds in every individual detection reported before the change.
Combined with detections on the sub-Antarctic Heard Island, that made Australia the last inhabited continent to be reached. On 29 July the outbreak crossed a second threshold: Agriculture Minister Julie Collins confirmed the virus is now spreading locally between Australian birds.
The national laboratory had linked seven cases in greater crested terns in South Australia to spread between birds rather than separate arrivals. Australia has since accepted that H5 bird flu is no longer technically feasible to eradicate in wildlife.
As chief veterinary officer Beth Cookson put it, once the virus is widespread in wild bird populations “it will not be possible to avoid losses in susceptible wildlife”. There is still no evidence of mass mortalities on the mainland, and Collins says the poultry industry remains unaffected.
On 30 July the spread reached a fifth state. Preliminary testing found H5 bird flu in a single greater crested tern at Portland, Victoria, with CSIRO’s Geelong laboratory running confirmatory genetic tests, and Victoria activated its State Emergency Animal Disease Response Plan.
Victoria had seven confirmed cases on 5 August, all greater crested terns: five at Portland and two at Nelson Bay. The state laboratory AgriBio flagged 33 further suspect cases that day, among them 30 greater crested terns, a gull and an inconclusive magpie, all sent to CSIRO for confirmation.
The magpie came back positive. CSIRO confirmed it on 6 August alongside a further 15 Victorian detections, making it Australia’s first H5 case in a land bird rather than a seabird.
Victoria has since reached 58 confirmed cases. On 13 August the state reported an infected wild bird at Mildura, well inland, adding to known clusters in south-west Victoria, the Great Ocean Road region, Gippsland and Melbourne’s south-east.
The state crossed another line on 18 August. Agriculture Victoria confirmed three further detections: a little penguin on Phillip Island, the state’s first case in a penguin, plus crested terns at Lakes Entrance and at Dromana on the Mornington Peninsula.
Lakes Entrance puts the virus in East Gippsland, well east of the original south-west cluster. Victoria still reports no detections in poultry or other animals, and the risk to human health there remains low.
Australia recorded its first mass mortality event. Aerial surveillance found 49 dead and 35 sick greater crested terns on Baudin Rocks, an islet about 5 km off the South Australian coast near Cape Jaffa. Testing announced on 3 August confirmed H5N1 in sampled carcasses.
Officials expect worse. Agriculture Minister Julie Collins said Australians should expect to see more spread and larger numbers now, and Environment Minister Murray Watt warned there will be more mass mortality events because wild birds cannot be stopped from flying.
South Australia’s chief veterinary officer Skye Fruean called the event unusual and significant, and said the situation appears to be escalating quite rapidly. There are still no detections in poultry, and the risk to human health is still rated low.
Three much larger events followed. On 20 August Premier Peter Malinauskas told the South Australian parliament that surveillance teams had found more than 1,000 dead crested terns across Troubridge Island off the Yorke Peninsula and the two Pages islands off Kangaroo Island.
The deaths were detected on 19 August and the birds are presumed to have died of H5N1. Malinauskas called it a significant escalation, and said the state was also investigating a suspected case in a little penguin from Kangaroo Island.
South Australia had 177 confirmed cases as of 20 August. No mass mortality has been reported in mammals, and there is still no detection in poultry or livestock.
Tasmania is the sixth jurisdiction
Tasmania recorded its first case on 13 August, a brown skua at Burgess Cove in Rocky Cape National Park in the state’s north-west, confirmed by CSIRO.
A week later the state was at 11 confirmed cases, spread across King Island, Rocky Cape, Burnie and Sulphur Creek. On 20 August a surveillance team found 28 dead little penguins and three dead crested terns at the Port of Grassy on King Island.
Those carcasses are still being tested, so this is not yet a confirmed mass mortality event. Premier Jeremy Rockliff said more teams were being sent to the island to expand surveillance and carcass collection.
The King Island toll has since grown to 51 dead little penguins, most of them around the Port of Grassy. Only two carcasses were fresh enough to test: one came back positive, the other inconclusive.
NRE Tasmania still does not class the Grassy deaths as a mass mortality event, because it cannot attribute all 51 deaths to the virus. Department secretary Jason Jacobi put the longer view plainly on 22 August: the virus is here to stay.
Jacobi warned the outbreak is likely to arrive in waves over months and years, with quiet spells broken by sudden spikes in deaths. Tasmania’s vaccination effort is focused on captive-bred orange-bellied parrots rather than wild penguins.
The virus reaches Australia’s mammals
Attention has turned to marine mammals. A dead seal pup found at Warrnambool on Victoria’s south-west coast was sent for testing in early August, and a positive bird detection was recorded near the endangered Australian sea lion colony at Seal Bay in South Australia.
That worry became fact on 23 August. CSIRO’s Australian Centre for Disease Preparedness confirmed H5 bird flu in a long-nosed fur seal found dead at Beachport in South Australia’s south-east, the first confirmed mammal case anywhere in Australia.
The seal was found with no sign of injury and reported to the emergency animal disease hotline by a member of the public on 19 August. Agriculture Minister Julie Collins said it was not unexpected to start seeing infection in other wildlife where wild birds are heavily infected.
Australia has roughly 13,000 sea lions, about 85% of them in South Australia. University of Adelaide wildlife veterinarian Wayne Boardman expects a high mortality event, pointing to the 30,000 sea lions killed by H5N1 in South America.
A day after the Beachport result, a second fur seal was reported as a suspected case at the Pages Conservation Park, the two islets off Kangaroo Island where more than 1,000 terns died. Samples went to Geelong for confirmatory testing.
The Pages hold one of the largest and most stable Australian sea lion colonies, a species now down to fewer than 10,000 mature adults. Jack Gough of the Invasive Species Council warned that if the virus gets into sea lions, this could be an extinction-level event.
South Australia’s environment minister Emily Bourke called the spread incredibly concerning, pointing to seal die-offs overseas. No H5 detection has yet been confirmed in an Australian sea lion.
On 13 August the Threatened Species Scientific Committee warned the virus could drive unavoidable and potentially catastrophic declines in susceptible Australian species, and urged harder action on feral predators and habitat loss so populations enter the wave with more resilience.
Vaccinating the birds that can be reached
With eradication off the table, the response has shifted to protecting what can be protected. On 11 August the federal government put about $2 million behind roughly 1,500 vaccine vials for a first phase aimed at vulnerable species in zoos and managed collections, with threatened black cockatoos named as a likely next target.
Agriculture Minister Julie Collins framed it bluntly: “We can’t stop the virus spreading amongst wild birds. We can take action to protect the species most at risk.” Chief veterinary officer Beth Cookson said broad-scale vaccination in the wild is “not practical or feasible”.
Victoria has now attempted the biggest exception to that rule. Vaccination of little penguins began on the evening of 17 August at Phillip Island, days after a penguin there died of H5, and extends to the St Kilda breakwater colony in Melbourne.
The target is more than 5,000 birds, which the state calls the largest vaccination effort ever attempted in a wild population. Little penguins are flightless and return to the same burrow each night, which makes them unusually catchable.
Victoria’s chief biodiversity officer James Todd called the scale unprecedented, and flagged the hard part: the vaccine works best in two doses, and wild animals rarely come back for the second. The Phillip Island colony holds about 40,000 birds in the breeding season.
The rollout passed its first milestone on 24 August, with about 1,000 penguins given a first dose. Roughly 10,000 doses are needed to finish the two-shot course, with second doses due three to four weeks after the first.
Phillip Island Nature Parks chief executive Catherine Basterfield called it the first mass vaccination program of this scale in the world. Worst-case modelling suggests an outbreak could kill 8,000 to 16,000 of the island’s penguins.
New Zealand followed days later. On 15 July it confirmed its first case, a brown skua recovered from Petone Beach in Wellington, and on 17 July a second, a swamp harrier found in the Wairarapa.
A third case followed on 21 August: a northern giant petrel found dead on a remote Cape Palliser beach in the Wairarapa. There is still no detection in poultry and no evidence of mass wildlife mortality.
Officials there are already planning for the virus to stay. MPI chief veterinary officer Mary van Andel says it is likely to become endemic in New Zealand within a matter of months. The Department of Conservation is vaccinating about 300 core breeding birds from five endangered species, among them the kakapo, takahe and shore plover.
H5N1 reached a European cow. In early 2026, a dairy cow in the northern Netherlands tested positive for H5N1 antibodies, the first cattle infection anywhere outside North America. Investigators traced it to a farm cat, an unsettling reminder of how easily the virus now moves between species.
The virus is now in Antarctica. Following its arrival in the far south during the 2023–24 season, H5N1 has been confirmed in Antarctic skuas, terns, seals and other wildlife, completing its spread to all seven continents and threatening some of the most isolated animal populations on Earth.
The sub-Antarctic toll is now measurable. Drone-survey results published by the Australian Antarctic Program on 18 June 2026 estimate that about 13,000 of roughly 17,000 southern elephant seal pups died on Heard Island, an average mortality of 76% in the final surveys and 97% in one breeding area.
Six species there tested positive for H5N1 clade 2.3.4.4b, including king and gentoo penguins and Antarctic fur seals, with several hundred dead adult king penguins recorded by January 2026. Genetic analysis points to the virus arriving around August 2025 with wildlife from the French Crozet Islands, about 1,800 km away.
The jump to cattle
The most worrying twist of this outbreak is that H5N1 learned to infect cattle. Since the first US dairy detection in March 2024, the virus has spread to more than 1,000 dairy herds across 17 to 19 states, with California the epicenter after hundreds of affected herds pushed the state to declare an emergency. The virus spreads through milking equipment and raw milk, which carries very high viral loads, and it has jumped from cattle to farm workers and barn cats.
Every mammalian host is a concern because mammals share more of our biology than birds do. Each infection is a fresh opportunity for the virus to acquire the mutations it would need to spread efficiently between people. The Dutch cow shows that cattle infection is no longer a North American anomaly.
Human cases: who has been infected
For all its spread in animals, H5N1 still infects people only rarely, and almost always after close contact with sick birds or livestock. But when it does, it can be deadly. Since 2003 the WHO has confirmed 993 human cases across 25 countries, of which 477 were fatal, a case-fatality rate close to 48%. The map below sizes each country by its cumulative case count and colours it by how lethal those cases were.
Egypt, Indonesia and Vietnam account for most of the historical total, a legacy of the mid-2000s poultry epidemics in Asia and North Africa. The pattern of the last two years looks different. Cambodia has become the current hotspot, with a cluster of eight cases and at least three deaths in 2025 tied to backyard poultry. The United States, by contrast, has recorded 71 cases since 2024 that were overwhelmingly mild, mostly among dairy and poultry workers, with a single death, in Louisiana in January 2025.
2003–2025
The countries where bird flu has infected people
Cumulative confirmed human cases of avian influenza A(H5N1), the ten most-affected countries.
| Country | Cases | Deaths | Fatal |
|---|---|---|---|
| Egypt | 359 | 120 | 33% |
| Indonesia | 200 | 168 | 84% |
| Vietnam | 130 | 65 | 50% |
| Cambodia | 90 | 52 | 58% |
| United States | 71 | 1 | 1% |
| China | 57 | 32 | 56% |
| Thailand | 25 | 17 | 68% |
| Türkiye | 12 | 4 | 33% |
| Bangladesh | 11 | 1 | 9% |
| Azerbaijan | 8 | 5 | 62% |
Could this become a human pandemic?
The honest answer is that no one knows, and that uncertainty is the point. The critical threshold, sustained human-to-human transmission, has not been crossed. Public-health agencies including the CDC still rate the risk to the general public as low, and the mild US cases are reassuring on that front.
What has changed is the sheer volume of the virus in the environment. Every infected flock, herd or wild bird is another roll of the dice. As Ed Hutchinson, a virologist at the University of Glasgow, put it in early 2026, the virus is now “raging around the world, and there is no feasible containment method other than just watching it infect huge populations of animals.” The more animals it infects, the more chances it has to adapt, which is why scientists watch the cattle outbreak so closely.
The bottom line
H5N1 in 2026 is a pandemic already, just not a human one. It is an animal-health catastrophe of unprecedented reach: on all seven continents, in more than 50 countries in a single season, in poultry, wild birds, seals, cats and cattle. For most people the day-to-day risk remains low, and the sensible precautions are simple: avoid touching sick or dead birds, and do not drink raw milk.
But the map is a warning. A virus this widespread, this lethal in the people it does infect, and now this comfortable in mammals, deserves the close attention it is getting. The next map worth watching is the one that would show human-to-human spread. So far, that map is blank, and the goal of global surveillance is to keep it that way.
Data and references (latest available as of 26 August 2026):
Image Sources
