#17,948
Despite lying beneath both the West Pacific and East Asian–Australasian Flyway - which funnel migratory birds from high latitudes of Alaska and Siberia south, deep into the Southern Hemisphere - Australia, New Zealand and the islands of Oceania have yet to see the arrival of HPAI H5.
Nine years ago, when HPAI H5N8 was winging its way around the world, we looked at Australia's Wild Bird Avian Influenza Surveillance, where their government reported:
Surveillance continues to show H5N1 avian influenza virus is not present in Australia. Waterfowl, which are the normal hosts of avian influenza and are thought to have had a role in the spread of the H5N1 virus in Europe, Asia and Africa do not migrate to Australia. A number of species of wading birds do migrate to Australia but they are not the normal hosts or spreaders of avian influenza. Australia’s strict quarantine measures prevent the disease coming into Australia through imported birds or poultry products.
Even though H5N1 emerged in Southeast Asia more than 25 years ago, and has been widely reported across much of the Indonesian archipelago and parts of New Guinea, the virus has never managed to get a foothold in Oceania.
This lack of HPAI H5 has often been attributed to the Wallace and Weber lines; imaginary dividing lines used to mark the difference between animal species found in Australia and Papua New Guinea and the rest of Southeast Asia (see 2008 study Will Wallace’s Line Save Australia from Avian Influenza?).
These stark faunal differences also extend to birds, reptiles, and even insects.
Importantly for avian flu, very few migratory birds appear to cross the Wallace line (see The Australo-Papuan bird migration system: another consequence of Wallace's Line).
That said, there were brief reports in 2007 of H5N1 being detected in poultry in both West Papua and the Maluku Islands; both of which lie on the Eastern side of the Wallace line. Details (and sequences) are limited, since the Indonesian government was notoriously refusing to share bird flu information at the time.
The arrival of HPAI H5 to Antarctica over the past few months (albeit, thousands of kilometers distant from Oceania - see map below) has the potential to provide the HPAI H5 virus with a different approach - from the south - assuming the virus is able to spread widely in Antarctica's wild birds and mammals.
Given movement data demonstrating connectivity between the polar front to both the Antarctic and Subantarctic islands of Oceania, and Oceania itself, it is plausible that if HPAI H5 were present in the Antarctic region directly south of Oceania, it could be introduced to Oceania.
Overnight the Australian Antarctic Program - a part of the Australian Government's Department of the Environment - published an update on their surveillance program for avian flu, which identified skuas as the biggest threat for bringing the virus into the country.
I've only posted some excerpts from a longer report. Follow the link to read it in its entirety.SEABIRD, SEAL MONITORING CRUCIAL AS AVIAN INFLUENZA REACHES ANTARCTICA
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14 MARCH 2024
Monitoring bird and seal colonies in Antarctica has taken on a new urgency with the detection of the highly pathogenic Avian Influenza on the continent for the first time. The Council of National Managers of Antarctic Programs (CONMAP) has confirmed that two dead skuas found near the Argentinian Primavera station on the Antarctic Peninsula tested positive to the virus in late February.
There were always fears Avian Influenza would reach Antarctica this season but seabird ecologist Dr Louise Emmerson said it was a shock nonetheless.
“It has had a devastating effect in nearby South America,” she said.
“Tens of millions of birds have died globally and there is evidence that it also had a dramatic impact on southern elephant seals and fur seals.
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Cruise ships adopt new biosecurity measures
Dr Emmerson spent some of the summer monitoring bird colonies for the virus from a cruise ship on the Antarctic Peninsula with a colleague from Oxford University in the UK.
Dr Emmerson and her colleague, Dr Tom Hart, would join the expedition team on a zodiac and head out on a scouting trip to a penguin colony.
They would visually scout for signs of the disease and go ashore first, to conduct drone surveys of the penguin colonies and check the site was clear for passengers.
At the time, there were no signs of the mass deaths or neurological symptoms characteristic of the disease, but biosecurity measures on cruise ships had been ramped up in response to the risk.
“Before passengers came down to get on a small boat to visit a penguin colony they’d take their hiking boots and poles and their backpacks and camera bags – anything they were going to take into the field, and they’d disinfect them.
“The cruise ship provided rubber boots for everyone to walk in, and an outer layer with a hood and walking poles for people to use so we could make sure everything was clean.
“Then when we got back, everyone would scrub their boots and poles and make sure everything that had touched the ground was disinfected.
“This year, we didn’t allow people to sit on the ground or put their packs on the ground. But the passengers were great about it, they took the risk to the wildlife and themselves very seriously.”
"The species we were always most worried about was skuas"
Some colonies along the Peninsula had been closed to visitors while suspect deaths were investigated but none were confirmed as Avian Influenza.
However by then, the virus was confirmed on South Georgia and the Falkland Islands.
“The species we were always most worried about was skuas because they’re scavengers and they undertake considerable winter migrations. For example, the skuas from East Antarctica fly all the way up to Japan, Korea and China so the chance of them being exposed to the disease was always greater. Penguins that breed in Antarctica don’t go very far north in winter so if they get it, it will be from other wildlife, including the northerly migrating seabirds, or humans.”
Camera network vital for monitoring
As part of the summer monitoring project, Dr Emmerson and Dr Hart also maintained and downloaded data from Dr Hart’s camera network, set up along the Antarctic Peninsula to monitor nesting sites.
The network is based on an idea pioneered in Hobart by Australian Antarctic Division engineers in the early 2000s.
The AAD’s network has about 44 cameras set up at key locations along the East Antarctic coastline, taking ten photos a day of about 30 to 40 nests per camera.
Species monitored include surface nesters like Adelie penguins, cape petrels, fulmars, southern giant petrels and emperor penguins.
“The cameras are on tripods and they’re very robust,” Dr Emmerson said.
“We can use the images to monitor when the birds arrive and leave, the timing of chick creche and their breeding success.
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The AAD will also revisit its bird flu management protocols.
“We need to make sure all our expeditioners know what their responsibilities are and where the disinfectant is and what to do if there are signs of the virus,” Dr Emmerson said.
“We can’t stop it spreading through the natural migratory process, but we can stop ourselves moving it around and that’s what we need to focus on.”
While the arrival of HPAI H5 to Oceania is far from assured, should it happen, the virus would gain access to a number of new avian and mammalian species (including marsupials), along with a fresh array of genetically distinct LPAI viruses which which to potentially reassort.
Whether that would ultimately help the virus is unknown, but it is an unsupervised field experiment that is best avoided if possible.
