A highly pathogenic strain of bird flu has been detected in Australia for the first time, in a child returning from overseas.
The report comes as Victorian authorities confirmed that a bird flu outbreak on an egg farm is not the H5N1 strain that is causing global concern but is another highly pathogenic strain.
The Victorian health department on Wednesday reported that a child who had recently returned to Australia from India had tested positive to the H5N1 virus. The child, who arrived in Australia in March, experienced a “severe infection” but has since made a full recovery and contact tracing has not identified any further cases of avian influenza.
The virus was detected through the state’s disease surveillance system, in which positive influenza cases are subject to further testing to identify novel or concerning flu virus strains.
It removes Australia’s status as the only continent not to have a confirmed case of H5N1 in a bird or mammal. The H5N1 strain has yet to be detected in birds in Australia.
Earlier, Agriculture Victoria reported that the avian influenza virus was detected at an egg farm near Meredith in western Victoria after a number of poultry deaths.
The Victorian chief veterinary officer, Dr Graeme Cooke, told the ABC Country Hour on Wednesday that the variant detected was H7N3, a type of high pathogenicity (HPAI) strain of avian influenza that has been detected in Australia before, most recently in Victoria in 2020 and 2021.
Cooke said that H7 subtype of HPAI was “the most common variety that occurs in Australia from time to time”.
“There is a type of virus which is causing great concern in the USA and other parts of the world and has behaved unusually in that it has infected dairy cattle and some other marine mammals and so on,” Cooke said. “This is not the strain that we’re dealing with. This is a strain that’s occurred in Australia before. It’s likely not new”.
He said he would “never say it’s a relief to have a type of high pathogenicity avian influenza”.
A global outbreak of the H5N1 subtype of HPAI has killed millions of wild birds and thousands of mammals on six continents, and devastated commercial bird populations.
It has spread to more than 40 species of mammals, including polar bears, and is widespread among dairy cattle in the US.
Only one case has been reported in a human in an apparent transfer of the virus from another mammal: a man in Texas who had been in contact with dairy cows. The World Health Organization has said the spread of the virus to dairy cattle is an “enormous concern” but the director general, Tedros Adhanom Ghebreyesus, this month said the virus had so far shown no signs of adapting to human-to-human transmission and public health risk remained low.
Cooke urged poultry farmers, back yard chook owners and other bird owners to report any unexplained bird deaths to the 24-hour emergency animal disease hotline or to their vet.
He said the current risk to the public remained low and that egg and poultry products “do not pose a risk and are safe to consume”.
Bird farmers and owners have been urged to maintain strong biosecurity practices and be on the look out for symptoms, which include sudden death, respiratory ailments, conjunctivitis and swelling of the head.
There have been eight outbreaks of HPAI influenza strains in commercial bird farms in Australia since 1976, all of which were successfully eradicated.
The 2020 outbreak in Victoria was the largest to date, and involved the highly pathogenic H7N7 avian influenza which was detected at three egg farms.
The low pathogenic H5N2 influenza was also detected at two turkey farms and low pathogenic H7N6 influenza was detected at one emu farm. The outbreak was declared over on 26 February 2021.
Cooke said to control this outbreak, there would be a “depopulation” of the “diseased and at risk” population of birds – reported to be hundreds of thousands at the one egg farm.
The Meredith property has been placed under quarantine and authorities have established an “intensive restricted movement zone” 5km around the property, with another controlled movement zone on a larger radius, in an attempt to stop the spread.
• This article was amended on 23 May 2024 to correct the variant of avian influenza identified at a Meredith egg farm. It was H7N3, not H7N7 as a previous version said.
