Key Takeaways
- H5N1 is now on every continent. Highly pathogenic avian influenza reached Antarctica in the 2023โ24 austral summer and mainland Australia in 2026, meaning the virus has now been detected on all seven continents. WOAH logged outbreaks in 43 countries in poultry and 53 in wild birds in the 2025โ26 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 2025โ26 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 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 on the mainland in mid-2026, and by July it had been found in native wildlife in South Australia. Combined with detections on the sub-Antarctic Heard Island, it made Australia the last inhabited continent to be reached.
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 2023โ24 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 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.
2003โ2025
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% |
| Tรผrkiye | 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 โraging around the world, and there is no feasible containment method other than just watching it infect huge populations of animals.โ 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 July 2026):
Image Sources
