Gentoo Penguin Tests Positive for H5N1 Bird Flu on Australian Territory

A Gentoo penguin has become the first bird confirmed to test positive for the H5N1 strain of avian influenza on an Australian territory, with samples showing the virus spreading on Heard Island in the sub-Antarctic region.

Earlier Cases on the Island

• The highly contagious virus had already been detected in Southern elephant seal populations on Heard Island in November 2025.
• The remote island lies about 4,000 km south-west of Perth and 1,700 km north of Antarctica.

Threat to Endemic Species

Experts warn the outbreak could endanger unique bird species found only on Heard Island, including:

• Heard Island cormorant
• Heard Island sheathbill

Losses among these species would have major biodiversity implications because they are endemic to the island.

Spread of H5N1 in Antarctica

The H5N1 virus first entered Antarctica during the 2023-24 season, with initial detections in South Georgia and later on the Antarctic Peninsula.

About H5N1 Bird Flu

According to the World Health Organization, avian influenza A(H5N1) is a subtype of influenza virus that mainly infects birds but can occasionally infect mammals and humans.

• The goose/Guangdong lineage of H5N1 first emerged in 1996 and has caused repeated outbreaks worldwide.
• Human infections are rare but can lead to severe illness with a high mortality rate, usually linked to close contact with infected birds or contaminated environments.

Sources: DTE & WHO