Scientists have proposed various explanations for why Australia and the entire Oceania region remain free from the avian influenza outbreak.
While the H5N1 avian influenza epidemic rages across the globe, Australia and the entire Oceania region remain unaffected. Scientists have offered several explanations for this phenomenon.
Researcher examining areas where positive cases of H5N1 were detected in Antarctica, March 2024. (Photo: AFP/TTXVN)
According to Mr. Frank Wong, a virologist at the Australian Animal Health Laboratory in Geelong, the geographic isolation and the policy of not importing live poultry have helped Australia avoid the epidemic. Additionally, many bird species here are endemic and do not migrate to affected regions.
However, Dr. Michelle Wille from the University of Melbourne suggests that the virus entering Australia is just a matter of time. Long-distance migratory birds, such as seabirds and shorebirds from Siberia and Alaska, passing through Southeast Asia to Australia may pose a potential risk of infection.
To proactively prevent this, Australian scientists have begun sampling nearly 1,000 migratory birds. They will catch albatrosses at seven locations stretching from the Northwest to the Southeast of the country to test for the virus, particularly the H5N1 strain 2.3.4.4b, which has caused mass mortality in birds and some mammals.
Moreover, ducks are also believed to be potential carriers of the virus. Ducks have a higher resistance to viruses due to their unique immune mechanisms, allowing them to transmit the virus without showing symptoms. Fortunately, most ducks in Oceania are endemic species that do not migrate overseas.
Another reason suggested is the biological division along the “Wallace Line” that runs through Indonesia. Many animal species live only on one side of this division, creating a distinct difference in fauna between the two regions.
This may mean the virus has not yet adapted to the species on the eastern side of the Wallace Line, including Australia.
Nevertheless, some duck species, such as the Pacific Black Duck and the Australasian Bittern, may still migrate across the Wallace Line, posing a risk of introducing H5N1 into the region.
Experts warn that if the virus is detected, the government will swiftly cull the affected poultry, as was done with the H7N3 and H7N9 strains in Victoria last May. However, the impact of the outbreak on Australia’s ecosystem remains a significant unknown that requires further research.
