Australian Bird Flu Tracker

History of the virus

History of the virus

The history of H5N1, and how Australia fits into it

Where this virus came from, how it spread across the world, and what is and is not part of the outbreak now under way in Australian wild birds. Every entry on this page carries a source you can open and read.

Bird flu is a family of viruses rather than a single one, and most of the confusion in news coverage comes from that. This page follows one lineage in particular: the H5N1 viruses descended from a virus found in domestic geese in southern China in 1996, and especially the branch of that family called clade 2.3.4.4b, which is the virus being found in Australian wild birds now.

Clade is the only piece of jargon you need. Influenza viruses are sorted into a family tree, and a clade is one branch of it: a group of viruses that share a recent common ancestor. The numbers, 2.3.4.4b or 2.3.2.1a, are just that branch's address. Two branches can carry the same name, H5N1, and still sit a long way apart on the tree.

Nothing here is asserted without a citation. Where a figure is approximate, ranged, or still being confirmed, the entry says so rather than rounding the doubt away. The Australian part of the record is generated from this tracker's own data and from official Australian statements, so it is rebuilt every day.

Three different viruses, three different events

A news report can be right that a detection is the first in a state while a tracker shows older records from that same state. Both can be true, because the older records are a different virus.

Influenza A viruses are named after two proteins on their surface, haemagglutinin, the H, and neuraminidase, the N. So H5N1 and H7N3 are separate viruses, not two versions of one virus. Australia's poultry outbreaks in 2024 and 2025 were H7. The virus in Australian wild birds now is H5N1. They are counted separately here and never added together.

Within H5N1 the same care is needed one level down. Australia's single human case, in 2024, was H5N1, but from clade 2.3.2.1a and acquired overseas. The wild bird detections from June 2026 are clade 2.3.4.4b. Same subtype name, different branch, different event.

H5N1, clade 2.3.4.4b
The current event. High pathogenicity H5N1 in Australian wild birds, first detected in June 2026 and still developing. This is the only thing shown in red on this site.
H7N3, H7N8, H7N9
A different subtype, in commercial poultry, across 2024 and 2025, and eradicated. Not part of the current event, never added to its count. Victoria, New South Wales and the Australian Capital Territory all hold records of this kind.
H5N1, clade 2.3.2.1a
One human case in 2024, acquired while travelling in India, and the person recovered. A different branch of the family tree from the virus in the birds, and unrelated to it. It is listed in the timeline below under Australia before June 2026.

The sourced entries behind this

How to read this page

Grey does not mean finished. The global outbreak is ongoing, and every entry states its own status in words. Only the Australian incursion is coloured, because that is the one place a reader could otherwise mistake an old and unrelated record for a new case.

A dotted label always has its reason printed under the entry: approximate, preliminary, reported rather than taken from a primary statement, or disputed between sources. Every entry ends with its sources. An entry that somehow reaches this page without one is labelled Unsourced rather than published quietly.

Timeline

Oldest first, and grouped so the current Australian incursion never sits beside an unrelated event without a heading between them.

Loading the timeline.

How this page is built

What the labels on an entry mean

Subject areas

To report sick or dead wild birds, call the Emergency Animal Disease Hotline on 1800 675 888. Do not handle sick or dead wild birds, and keep pets away from them.