A dolphin has died from H5 bird flu in South Australia, marking the second native mammal species known to have contracted the virus. The death adds to growing concerns about the spread of the highly pathogenic avian influenza among wildlife populations beyond birds.
Separately, expeditioners at a research station on Macquarie Island in the sub-Antarctic will be evacuated over possible psychological stress. The move comes as authorities assess the impact of the virus on remote wildlife populations and the researchers who study them.
On Friday afternoon, the Tasmanian government said it was assessing the discovery of about 100 dead little penguins on King Island. Officials were unable to test the birds for H5 bird flu due to their decayed condition, leaving the cause of death unconfirmed.
The dolphin death represents a significant development in the ecology of the outbreak. Scientists have documented H5 bird flu primarily in avian species, but the virus has shown an increasing ability to cross species barriers. The infection of a second native mammal species raises questions about the virus's adaptation and its potential to spread through marine and coastal ecosystems.
The evacuation of researchers from Macquarie Island highlights the human dimension of the outbreak. The Tasmanian government cited psychosocial risk as the reason for withdrawing expeditioners, acknowledging the psychological toll that working in a remote, high-stress environment during an active wildlife disease event can take. The island is a critical site for studying sub-Antarctic ecosystems, including seal and seabird populations that may be vulnerable to the virus.
The discovery of the dead little penguins on King Island adds another layer of concern. Little penguins are the smallest penguin species and are found along the southern coasts of Australia and New Zealand. Mass mortality events among these birds could signal a broader ecological impact, though the decayed condition of the carcasses prevented definitive testing.
Wildlife health experts have been monitoring the spread of H5 bird flu since it began causing unusual mortality events in wild birds and mammals. The virus has been detected in a range of species, including foxes, bears, and marine mammals in other parts of the world. The confirmation of infections in native Australian mammals suggests the virus is establishing a foothold in new ecosystems.
Authorities are urging the public to report sightings of sick or dead wildlife, particularly birds and marine mammals, to help track the spread of the virus. They also advise against handling dead animals without proper protective equipment, as the virus can pose a risk to humans in rare cases.
The situation remains fluid, with ongoing assessments of the penguin deaths on King Island and continued monitoring of the outbreak's trajectory. The combination of mammal infections, researcher evacuations, and unexplained bird deaths underscores the complex challenges posed by this pathogen in remote and sensitive environments.
