HPAI Confirmed In Penguin Populations On South Georgia

Credit OFFLU 

#17,945

Seven months ago, we looked at the FAO/WOAH OFFLU Network's 14-page statement on the impacts, and challenges of HPAI facing South America, and the strong likelihood that avian flu would soon arrive in the Antarctic region. 

Two months later (Oct. 2023) we learned of the first confirmed HPAI H5 infection in a bird in the sub-Antarctica region from the Government of South Georgia & the South Sandwich Islands' (SGSSI) twitter/X account.

In mid-January, in SGSSI Statement: HPAI Confirmed in Mammals in Sub-Antarctica For The First Time, we learned the virus had been detected in elephant and fur seals on the sub-Antarctic island of South Georgia.

And just two weeks ago (see CIDRAP report), HPAI was confirmed on Antarctica's mainland; recovered from dead skuas which were found by Argentine scientists near the “Primavera” Antarctic base. 

Overnight SGSSI website published the following update, confirming the discovery of HPAI in two colonies of penguins (gentoo & king) on South Georgia. 

HPAI Confirmed In Penguin Populations On South Georgia

March 11, 2024

Highly Pathogenic Avian Influenza (HPAI) was first detected in the brown skua population on Bird Island, South Georgia in October 2023.

Since then, British Antarctic Survey (BAS) scientists and Government of South Georgia & the South Sandwich Islands (GSGSSI) personnel have undertaken monitoring across the Territory. The teams have been closely supported by the UK Animal and Plant Health Agency (APHA) via testing at their laboratories in Weybridge.

HPAI has now been confirmed from 23 sites across South Georgia. Species which have historically tested positive for HPAI H5N1 include: brown skua, kelp gul, wandering albatross, elephant seal and Antarctic fur seal.

The most recent results from samples taken in early February have confirmed the presence of the disease in one colony of gentoo penguins and one colony of king penguins on South Georgia.

Whilst the virus has been detected at a range of sites and in several species, the effects appear to be localised. GSGSSI will continue to work with partner agencies to monitor the impact of the disease on wildlife in the Territories.

Genomic sequencing surveillance data analysed to-date has confirmed previous assessments that there is no increased risk to human health. The risk of human infection with H5N1 remains very low.

Guidance for those visiting the Territory is available in the Biosecurity Handbook. As part of the response to HPAI, some sites on South Georgia are closed to visitors. At other sites, visitors are asked to continue following established biosecurity procedures to decontaminate clothing, footwear and field equipment before and after any landing between regions and sites.

You can find more details and background in the British Antarctic Survey news report Penguins test positive for Avian Flu on South Georgia.

Remarkably, even though H5N1 emerged in Southeast Asia more than 25 years ago, and has been widely reported across much of the Indonesian archipelago for decades, the virus has never managed to get a foothold in Oceania (Australia/NZ).

It has long been believed that that this good fortune is due 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.

While separated by a relatively narrow strait, on the western side you'll find Elephants, monkeys, leopards, tigers, and water buffalo while on the eastern side, you'll mostly find marsupials (kangaroos, Koalas, wombats, etc.).

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).

The continued expansion of HPAI H5 in the Antarctic region however, potentially provides the virus with a new approach (from the south) to both Australia and New Zealand. While that hasn't happened yet, it may become a possibility down the road. Last December OFFLU warned:

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.

Whether or not that happens, HPAI H5's global field experiment continues, and there appears to be little we can do to stop it.