Fur seal’s death marks first Australian mainland mammal fatality from H5 bird flu

First Mainland Mammal Fatality Confirmed in South Australia

The death of the long-nosed fur seal on the Limestone Coast represents a critical escalation in Australia’s ongoing encounter with the highly pathogenic H5 bird flu strain. Found dead at Beachport on Wednesday on the state’s Limestone Coast, the animal’s infection brings the virus out of offshore island settings and directly onto the Australian mainland’s coastal mammal populations.

Just days prior, South Australian Premier Peter Malinauskas announced three separate mass mortality events on offshore islands involving more than 1,000 greater crested terns. Concurrently, state officials confirmed that a little penguin found at Kangaroo Island this week also tested positive for H5 bird flu, underscoring a broadening exposure footprint across native fauna.

The highly pathogenic strain of bird flu has killed millions of birds globally and crossed over into mammal species, including elephant seals. Long-nosed fur seals and the endangered Australian sea lion are among the mammal species the federal government has assessed as facing very high risk from the virus.

Seabird Infections and the Migratory Vector

The detection of the virus in a native bird represents what the federal government described as a concerning development, because previous confirmed cases have involved migratory birds from the sub-Antarctic region. Agriculture Minister Julie Collins said CSIRO lab testing had confirmed the deadly strain in a greater crested tern found in Robe in South Australia’s Limestone Coast.

There have also been two further confirmed cases in South Australia and one in Western Australia, bringing the total number of detections to 12. Julie Collins says further work is being carried out.

Ms Collins said there was still no evidence of mass mortality among wildlife and no evidence of any spread to agricultural settings. The minister said SA authorities were implementing enhanced surveillance in the area where this bird was found, and that further investigation was being conducted to determine how the bird contracted the virus.

Our scientists are undertaking further work to establish the potential pathway that resulted in the Australian seabird's infection, she said.

H5N1 avian flu spreads among Australian bird population

[They will] seek to determine whether this particular tern has caught off these migratory birds, if it's the same sort of sequence or not.

What we do know is that this is a coastal seabird that has an overlapping coastal range with migratory seabirds that have previously tested positive for H5.

The greater crested tern was found by a member of the public a few days ago, and was reported to the Emergency Animal Disease Hotline. The bird was sent to the CSIRO, which confirmed the case of H5 bird flu, the minister said. She said no other dead birds were found nearby.

“While this is a concerning development, it is not unexpected and is another sign that our strong biosecurity system is working.”

Julie Collins, Agriculture Minister

Surveillance, Regional Checks, and Marine Mammal Risk

Later on Friday afternoon, the NSW Department of Primary Industries and Regional Development (DPIRD) said a deceased juvenile fur seal found at Blue Bay on the Central Coast tested negative to H5N1.

Seals are regularly seen along the NSW coastline at this time of year, and reports of sick or injured juvenile seals are not uncommon, a DPIRD spokesperson said. It said it was continuing to work with its environment department on ongoing wildlife surveillance.

South Australia’s two previous confirmed cases of H5 bird flu have been on Yorke Peninsula and Kangaroo Island. Department of Primary Industries and Regions SA (PIRSA) chief veterinary officer Skye Fruean said the sea lion population on the latter was potentially exposed.

We've already done a huge amount of preparatory work to build the res…

Confirmed bird flu cases span multiple regions and dates:

• Brown skua found in Esperance, WA on June 14
• Giant petrel found on the Fleurieu Peninsula, SA on June 14
• Giant petrel found in Esperance, WA on June 18
• Giant petrel found in Quindalup (Dunsborough), WA on June 20
• Giant petrel found in Esperance, WA on June 21
• Giant petrel found in Mullaloo (Perth), WA on June 30
• Giant petrel found in Hawkes Nest, NSW on July 1
• Giant petrel found in Hardwicke Bay, SA on July 3
• Giant petrel found in Port Vincent, SA on July 6
• Giant petrel found on Kangaroo Island, SA on July 6
• Giant petrel found in Mullaloo (Perth), WA on July 8
• Greater crested tern found in Robe, SA, date unknown

Note: The Mullaloo case is presumed positive due to the decomposition of the carcass.