South Africa - Forestry, Fisheries and the Environment on High Pathogenicity Avian Influenza suspected on sub-Antarctic Marion Island

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Forestry, Fisheries and the Environment on High Pathogenicity Avian Influenza suspected on sub-Antarctic Marion Island

12 Nov 2024
High pathogenicity avian influenza suspected on sub-Antarctic Marion Island

High pathogenicity avian influenza (HPAI) virus is suspected to have reached Marion Island, one of South Africa’s two sub-Antarctic islands in the southern Indian Ocean and is possibly responsible for causing mortalities in at least three breeding seabird species.

After an initial suspected case in a Brown Skua in mid-September 2024, another five suspected cases were found in early November 2024, involving three Wandering Albatross chicks and two Southern Giant Petrel adults. The virus can be transported long distances by migrating birds, and this is likely how the virus arrived on Marion Island.

Having spread across the globe since 2021, HPAI (H5N1) was detected in seabirds and marine mammals in South Georgia, southeast of South America, in October 2023. It reached Antarctica in February 2024 and suspected cases were reported from Southern Elephant Seals at Possession Island in the Crozet Archipelago, east of Marion Island, on 21 October 2024.

The Prince Edward Islands, comprising Marion Island and Prince Edward Island, are breeding and moulting sites for millions of seabirds, including almost half of the world’s Wandering Albatrosses and hundreds…

https://www.gov.za/news/media-statements/forestry-fisheries-and-environment-high-pathogenicity-avian-influenza

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NEWS
December 18, 2024

Bird flu suspected on Marion Island in South Africa

Half of the world's wandering albatross population could be under threat

By Engela Duvenage
...
At least 100 wandering albatross ( Diomedea exulans ) chicks are believed to have died from highly pathogenic avian influenza (HPAI) on the sub-Antarctic island of Marion, home to half the world's population of the critically endangered birds. Since the first cases were suspected two months ago, at least a dozen sick king penguins have also been reported.

Field work involving the handling of seabirds on the South African research island has been suspended. Peter Mbelengwa, director of communications at the South African Department of Forestry, Fisheries and Environment (DFFE), said that given the number of cases observed at the end of November, the island was placed on alert level 2. “This requires us to continue monitoring as usual, but we have adopted more precautionary measures such as a ban on handling seabirds,” he added.

Laura Roberts, State Veterinarian for Epidemiology at the Department of Agriculture in South Africa's Western Cape Province, says the protocol echoes the actions taken by authorities when HPAIV subtype H5N1 clade 2.3.4.4b was first detected1 in seabirds and marine mammals in South Georgia, southeastern South America in October 2023.

It is not validated that the seabird deaths on Marion Island are actually caused by HPAIV, as there are no specialized laboratory facilities on the island. Roberts, who helped develop the protocols after the 2017 bird flu outbreak in South Africa, says the samples collected and frozen will likely not be tested until May 2025, when the current research team returns to South Africa by boat. The HPAIF hypothesis is based on images reviewed by a panel of experts.

The telltale signs of the disease, such as lethargy and convulsions, were first observed in September in brown skuas that had returned to Marion Island to breed in the spring. So far, most cases have come from the north-east of the island, around Goney Plain, where wandering albatrosses breed, and fewer have been on Kildalkey in the south-east, where king penguins breed. A few sick southern giant petrels have also been observed.

"The mortality of young wandering albatrosses continues, but survivors are regularly leaving the island, which gives us hope." Ms Roberts added, however, that relatively few dead skuas have been found on the other side of the island, so the virus could be present everywhere.

"We also hope that SA Agulhas II will be able to drop off more PPE and other supplies en route to Antarctica in the coming weeks," she said.

The 11-member wintering team receives constant advice from a team of experts via WhatsApp, one of the few effective modes of communication from the island’s base camp. Roberts said the team received preventative training and protocols for recognizing symptoms of avian flu in seabirds and seals before leaving for the island. More disposable protective clothing, such as masks and goggles, was distributed than usual to be worn during field work.

Peter Ryan, an Antarctic seabird expert and emeritus professor at the FitzPatrick Institute of African Ornithology at the University of Cape Town (UCT), South Africa, says: "We are concerned about wandering albatrosses, partly because they have been the main species affected so far, and partly because Marion and Prince Edward Islands together are home to almost half the world's population," he explains.

Mr Ryan notes that the number of chicks affected so far is "tiny compared to the islands' annual production".

Because there are no roads or vehicles on the windswept island, all monitoring is done on foot over extremely rocky or muddy terrain, says a researcher who has worked on Marion Island, Stefan Schoombie of the University of Southern California's Center for Ecology, Environment and Conservation Statistics (SEEC). The far end of the island is about 20 miles from base camp.

Mbelengwa said the experience of previous bird outbreaks in South Africa, one of which killed about 25,000 Cape cormorants, had put authorities on alert.

The Prince Edward Islands are also home to large numbers of southern elephant seals and subantarctic and Antarctic fur seals.

"Every species is vital. We are concerned about all species, including mammals. If this spreads to many species that breed on the island, the consequences could be disastrous."

According to a paper in Nature Microbiology 2 , the HPAIV H5N1 virus has, in recent years, "caused unprecedented mortality in wildlife worldwide." Mass die-offs of seabirds and marine mammals in South America in 2022 raised concerns that it could also spread to many remote and hard-to-reach Antarctic sites. The paper, published in November 2024, confirmed that the virus was already present in the northern Antarctic region. The international research team worked in the field in March and April 2024 and conducted molecular diagnostic tests aboard the Australis .

doi: https://doi.org/10.1038/d44148-024-00346-w

https://www.nature.com/articles/d44148-024-00346-w