Australia confirmed its first case of H5N1 bird flu, detecting the strain in a migratory brown skua found in remote Western Australia. The country had been the only continent where H5N1 had not previously been identified, so the finding extended the virus's recorded reach to every continent.
Agriculture Minister Julie Collins announced the result on Saturday. The bird was found on a beach in Cape Le Grand National Park, near Esperance and about 700 kilometres (434 miles) southeast of Perth, according to local reporting. Collins said authorities had expected that Australia would not remain free of the virus indefinitely.
A second bird, an exhausted southern petrel discovered on an Esperance beach, was being treated as a suspected case. Collins said there was no evidence at that time of mass deaths. Threatened Species Commissioner Fiona Fraser said authorities expected to know within a few days whether H5N1 was present in other Australian animal populations.
Chief Veterinary Officer Beth Cookson said officials had prepared for the arrival of the virus for a long period. Australia's emergency animal-disease committee convened on Saturday following the confirmed detection. The response focused on determining whether the finding represented an isolated infected migratory bird or wider transmission.
H5N1 can spread rapidly through wild and domestic bird populations. It can also infect mammals, including foxes, seals and otters. Human infections associated with the disease remain uncommon and usually involve contact with ill animals. The strain now circulating widely among wild birds first emerged in China in the late 1990s, and migration has carried it between regions.
Although this was the first confirmed case in Australia itself, H5N1 had been detected in October of the previous year on the remote Australian territories of Heard Island and the McDonald Islands in the southern Indian Ocean. Scientists believed migrating birds had probably brought the virus to those islands from the French-owned Crozet Islands, about 1,800 kilometres away.
The consequences there were severe. A study estimated that approximately 13,000 pups from a group of 17,000 seals on Heard Island had died from H5N1 since the previous August, representing more than 75% of that group. Researchers also reported higher-than-expected penguin deaths.
The Western Australian finding did not by itself establish comparable spread on the mainland, and officials had not observed mass mortality. It did, however, end Australia's status as the last continent without a confirmed detection and triggered surveillance to establish whether other animals had been infected.
Testing of the petrel and broader surveillance were the next steps in determining the mainland extent of the infection.
