On Saturday, a suspected case of fatal [H5 bird flu], often referred to as prime pathogenicity avian influenza (HPAI) H5N1, used to be showed in a brown skua.
This massive seabird used to be present in Cape Le Grand Nationwide Park close to Esperance, about 700 kilometres south-east of Perth in Western Australia.
The virus may be suspected to have affected some other seabird, a southern large petrel, discovered on the similar house.
This virus has devastated natural world populations in different continents, and this might be the beginning of a protracted push to offer protection to Australian birds and natural world in Australia.
The place did this virus come from?
Avian influenza viruses, of which HPAI H5N1 is only one type, had been round for millenia. Within the overwhelming majority of circumstances they motive no illness in birds. Those traces are known as low pathogenicity avian influenza viruses.
On the other hand, in 1996 any such viruses advanced to change into illness inflicting, and because then, this HPAI H5N1 has led to critical illness in poultry, and has change into endemic in poultry. With chickens now forming about 70% of all birds international, this can be a vital reservoir the place the virus continues to conform.
The devastating impact of HPAI H5N1 is sadly now not restricted to poultry. Since 2021, HPAI H5N1 has led to an international animal pandemic, with huge penalties for natural world in all continents. It has killed thousands and thousands of untamed birds and led to important drops within the world inhabitants of a few species. It has additionally unfold into wild and home mammals, with quite a lot of species of seals specifically affected.
The way it spreads
A part of the problem in controlling HPAI H5N1 is that it might probably unfold thru quite a lot of transmission pathways. For instance, the virus normally spreads thru faeces, particularly when in water. Believe inflamed geese in a pond, the place the pond water acts as a conduit to infecting different geese which might be feeding or cleansing themselves.
It will also be unfold thru direct touch and aerosol transmission, specifically in poultry farms. And it’s unfold thru predation and scavenging, the place animals like foxes possibly devour the carcasses of inflamed birds they in finding.
Whilst it has up to now been discovered in additional than 400 other chicken species, the unfold of HPAI H5N1 within the northern hemisphere is facilitated by way of freshwater dabbling geese. Dabbling duck species feed predominantly on the floor of the water, now and again even grazing on land.
Importantly, geese have very restricted indicators of illness when inflamed with HPAI H5N1, and seem in an effort to proceed emigrate whilst inflamed, letting them doubtlessly unfold the virus lengthy distances.
Total, this virus has been devastating for wild birds. For instance, 33–47% of all grownup northern gannets died in 2022 because of HPAI H5N1. On subantarctic Heard Island, 13,000 child southern elephant seals died because of HPAI throughout the 2025–26 summer time.
The virus’s unfold is particularly facilitated by way of freshwater dabbling geese.
Sandra Standbridge/Getty
Why has it taken goodbye to succeed in Australia?
Regardless of being in Asia for the reason that Nineties, and in Antarctica since 2024, HPAI H5N1 has now not been detected in Australia till now. That is most probably as a result of there aren’t any duck species which automatically migrate between Australia and Asia, nor are there geese that migrate thru Antarctica.
Regardless of the loss of geese in Antarctica, the virus did arrive there in the summertime of 2023–24, and due to this fact unfold 1000’s of kilometres in the course of the subantarctic in the summertime of 2024–25. To be had proof suggests birds like gulls, skuas and large petrels could have taken at the function of lengthy distance virus carriers within the Antarctic and subantarctic.
The quite a lot of species of skuas and large petrels that breed in Antarctic waters pass directly to roam the Southern Ocean, additionally venturing into the Atlantic, Indian and Pacific Oceans throughout the southern hemisphere iciness. Whilst infrequently noticed on our shores, those species don’t seem to be too a long way offshore, searching for meals and on occasion collecting in massive teams.
Now that HPAI H5N1 has been discovered on mainland Australia, it’ll now not essentially identify itself and unfold around the continent into different birds and mammals, together with cattle.
For the reason that skuas and large petrels are marine relatively than freshwater species, and don’t happen on land in massive numbers outdoor the breeding season, there may be nonetheless an opportunity that it won’t unfold additional.
The most important chance is that inflamed, ill birds are eaten or scavenged by way of local birds and mammals, which might transmit the virus to geese.
Attempt to forestall the unfold
As soon as in geese, the most probably unfold of the virus will increase dramatically, and the outlook can be grim.
However for now, we’re a couple of vital steps clear of that taking place. Persevered surveillance and trying out, being led by way of Western Australia, is significant to expose the level of the virus and whether or not it has unfold to native animals.
Vigilance is essential – don’t contact or take ill animals into your care. Moderately, file suspected circumstances right away to the Emergency Animal Illness Hotline on 1800 675 888.
For farmers or individuals who personal chooks, its vital to observe pointers equipped by way of govt departments and file any suspicious mortality.
