On Saturday, a suspected case of fatal [H5 bird flu], often referred to as top pathogenicity avian influenza (HPAI) H5N1, was once showed in a brown skua.
This massive seabird was once present in Cape Le Grand Nationwide Park close to Esperance, about 700 kilometres south-east of Perth in Western Australia.
The virus could also be suspected to have affected some other seabird, a southern large petrel, discovered on the similar house.
This virus has devastated flora and fauna populations in different continents, and this may well be the beginning of a protracted push to give protection to Australian birds and flora and fauna in Australia.
The place did this virus come from?
Avian influenza viruses, of which HPAI H5N1 is only one sort, had been round for millenia. Within the overwhelming majority of circumstances they reason no illness in birds. Those traces are known as low pathogenicity avian influenza viruses.
Alternatively, in 1996 any such viruses developed to develop into illness inflicting, and because then, this HPAI H5N1 has brought about critical illness in poultry, and has develop into endemic in poultry. With chickens now forming about 70% of all birds international, this can be a important 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 brought about an international animal pandemic, with monumental penalties for flora and fauna in all continents. It has killed thousands and thousands of untamed birds and brought about important drops within the international inhabitants of a few species. It has additionally unfold into wild and home mammals, with quite a lot of species of seals in particular affected.
The way it spreads
A part of the problem in controlling HPAI H5N1 is that it could actually unfold thru quite a lot of transmission pathways. For instance, the virus most often spreads thru faeces, particularly when in water. Consider 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 can be unfold thru direct touch and aerosol transmission, in particular 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 chook 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, infrequently even grazing on land.
Importantly, geese have very restricted indicators of illness when inflamed with HPAI H5N1, and seem so that you could proceed emigrate whilst inflamed, permitting them to 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 season.
The virus’s unfold is particularly facilitated by way of freshwater dabbling geese.
Sandra Standbridge/Getty
Why has it taken see you later to succeed in Australia?
Regardless of being in Asia for the reason that Nineteen 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 are not 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 therefore unfold hundreds of kilometres throughout 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 wintry weather. Whilst hardly observed on our shores, those species don’t seem to be too some distance offshore, in search of meals and from time to time accumulating in huge teams.
Now that HPAI H5N1 has been discovered on mainland Australia, it’s going to now not essentially determine itself and unfold around the continent into different birds and mammals, together with farm animals.
For the reason that skuas and large petrels are marine slightly than freshwater species, and don’t happen on land in huge numbers out of doors the breeding season, there may be nonetheless an opportunity that it would possibly not unfold additional.
The most important chance is that inflamed, in poor health birds are eaten or scavenged by way of local birds and mammals, which might transmit the virus to geese.
Attempt to prevent the unfold
As soon as in geese, the most probably unfold of the virus will increase dramatically, and the outlook could be grim.
However for now, we’re a couple of important steps clear of that going down. Endured surveillance and trying out, being led by way of Western Australia, is important to expose the level of the virus and whether or not it has unfold to native animals.
Vigilance is vital – don’t contact or take in poor health animals into your care. Slightly, file suspected circumstances right away to the Emergency Animal Illness Hotline on 1800 675 888.
For farmers or individuals who personal chooks, its important to apply pointers equipped by way of executive departments and file any suspicious mortality.
