Wildlife scientists aboard Australia's icebreaker believe a deadly strain of bird flu has reached the sub-Antarctic Heard Island after they witnessed unusual levels of mortality in elephant seals.

The suspected arrival of bird flu on the island can't be confirmed until samples are tested when the ship returns to Australia in several weeks.

• Guest: Dr Michelle Wille, senior scientist at the World Health Organisation's Collaborating Centre for Reference and Research on Influenza
• Producers: Teodora Agarici and Joe Sullivan