Australia warns H5N1 likely to spread after first mass mortality episode

Australia has detected its first mass mortality event linked to H5N1 bird flu, with testing confirming the virus in a group of greater crested terns discovered off Cape Jaffa, approximately 250 kilometres south of Adelaide. The discovery involved 49 dead birds and 35 sick birds found on rocks during helicopter surveillance on Friday. Agriculture Minister Julie Collins announced the findings on Monday, cautioning that Australians should anticipate increased spread and larger numbers of affected wildlife in coming months.

Despite the wildlife outbreak, there remains no evidence of H5N1 on Australian farms, many of which have implemented lockdown measures to protect poultry flocks since the virus was first detected in the country in June. Federal Environment Minister Murray Watt acknowledged that preventing the spread among wild and native birds is not feasible, as these animals cannot be contained from moving across landscapes. He indicated that additional mass mortality events similar to the current episode are likely to occur.

Australia and New Zealand, which reported its first H5N1 case last month, have spent years preparing for the virus's arrival through enhanced biosecurity measures at farms, testing of shore birds, vaccination programmes for vulnerable species, and contingency planning. Globally, H5N1 has caused significant mortality among birds and mammals, resulting in billions of dollars in losses to poultry producers and infecting cattle in the United States. While the virus can infect humans through contact with infected animals, the number of human cases worldwide remains small and officials assess the risk to human populations as low.