Australian authorities are investigating the death of a seal pup in Warrnambool, Victoria, as a potential first H5 bird flu case on the mainland in a mammal. This comes after a positive bird flu case was confirmed near an endangered Australian sea lion colony on South Australia's Kangaroo Island. Wildlife veterinarian Wayne Boardman of the University of Adelaide warns that Australian sea lions, with 85% of their 13,000-strong population in South Australia, could face a mass mortality event similar to the 30,000 sea lions killed by bird flu in South America.
The alarm was raised after the baby seal washed ashore and was cordoned off. Victoria's Department of Environment, Energy and Climate Action confirmed the seal's death and is investigating, urging the public not to approach sick wildlife. Globally, bird flu has been recorded in over 100 wild mammal species, and more than 13,000 elephant seal pups, or 97% of the pups, are estimated to have died on Heard Island in the Southern Ocean since the virus was detected there late in 2025.
Australia's national bird flu tally now exceeds 100 confirmed or presumed positive detections of H5 bird flu, with 123 cases reported. While there have been no detections in poultry or agriculture, and the risk to human health remains low, the Western Australian government has advised pet owners to be vigilant. Experts are concerned that predatory animals like feral cats, foxes, and dingoes could accelerate the disease's spread. The Australian government has conducted pilot bird flu vaccination trials, but a wide-scale public program has not yet been announced, with experts noting the significant logistical challenges of vaccinating sea lions.
