In a development that's about as welcome as a seagull at a picnic, South Australia has reported its first confirmed case of H5 bird flu in a mammal on the Australian mainland. A long-nosed fur seal was found dead at Beachport on the state's Limestone Coast on Wednesday, marking a grim milestone in the virus's relentless march across the globe.

This comes hot on the heels of the South Australian premier, Peter Malinauskas, announcing three mass mortality events on offshore islands involving over 1,000 greater crested terns. Because apparently, the birds weren't enough - now the virus is branching out into the mammal department.

The highly pathogenic strain has already racked up a body count of millions of birds worldwide and has previously crossed over into mammals, including elephant seals. Now, it's setting its sights on Australian shores, with long-nosed fur seals and the endangered Australian sea lion identified by the federal government as facing 'very high risk' from the virus. Not exactly the kind of list you want to top.

And just to keep the bad news rolling, a little penguin found at Kangaroo Island this week also tested positive for H5 bird flu. So, if you're a marine mammal or a penguin in South Australia, it might be a good time to invest in some PPE. Or at least, a very long snorkel.