Bird Flu Detected in 8th Victorian Farm

A domesticated Rhode Island red chicken in Takoma Park, Md., on May 20, 2021. (Chip Somodevilla/Getty Images)

The highly pathogenic H7N3 bird flu has been detected at yet another commercial egg farm in Victoria, Australia.

This comes after a second case of bird flu was confirmed in the Hawkesbury region of New South Wales (NSW).

Agriculture Victoria confirmed the eighth Victorian case of avian influenza virus had been discovered at a farm that was already in lockdown.

The bird flu was discovered after testing within the restricted area in the Golden Plains Shire in Victoria.

The government said all poultry at the property will be “humanely disposed of” under veterinary supervision. However, they did not specify how many birds would be impacted by the cull.

Victorian chief veterinary officer Graeme Cooke said movement restrictions are expected to be in place for several weeks.

“We’re continuing to work with affected producers and the poultry industry to respond to these detections through ongoing testing and careful biosecurity practices.”

He said Agriculture Victoria’s comprehensive and ongoing surveillance activities are “finding the infections and containing them.”

“The detection is not unexpected and in fact shows that risk-based restricted and control areas are reasonable and that our surveillance measures are working as we want them to.”

Movement controls near Meredith and Lethbridge have been extended to the west, while existing movement controls near Terang continue to be enforced.

Permits are needed to move birds, poultry products, feed, and equipment on or off properties within these restricted and control areas.

Eggs and Other Poultry Products Safe: Agriculture Victoria

Agriculture Victoria reassured the community not to be worried about the safety of eggs and other poultry products.

“They do not pose a risk and are safe to consume. Victoria has a secure supply chain including the importation of eggs from interstate, so the current outbreak has not significantly affected supplies,” the department said.

On June 17, the department confirmed a seventh case of high pathogenicity H7N3 strain bird flu at a commercial egg farm in Victoria.

An estimated one million birds in Victoria have been euthanised to halt the spread of bird flu.

Current Situation in Australia

Overall, the high pathogenicity H7N3 strain has been detected at seven properties near Meredith, while H7N9 strain has been discovered at one property near Terang in Victoria.

Meanwhile, in NSW on June 22, the state government confirmed a second case of highly pathogenic avian influenza. The H7N8 strain detected in NSW is separate to that discovered in Victoria.

Days earlier, a biosecurity emergency incident plan had been activated after the first case was detected.

In response, NSW Agriculture Minister Tara Moriarty said, “This is the same virus as the nearby site in Hawkesbury, which is, however, different to the virus impacting seven farms in Victoria. Importantly, testing has shown that the NSW cases are not H5N1 strain that is causing concern globally.”

“This type of avian influenza is highly infectious in commercial poultry and it was always a possibility that we could detect sites within the control zone. The government will continue its testing at sites,” she added.

More than 300,000 birds in NSW have been or are in the process of being culled.

The recently delivered NSW state budget included $946 million for protecting state and our primary industries from biosecurity threats.

Bird Flu Causes

Bird flu is caused by a “variety of influenza type A viruses” that usually infect birds, according to Murdoch University Professor of Viral Immunology Cassandra Berry.

“The difference lies in the number of basic amino acids at the cleave site of haemagglutinin (HA), a spike protein on the virus surface, which is cleaved by cellular proteases,” she said.

“This cleavage determination then allows the virus to infect cells of different tissues and organs in the body. So if the virus HA is more easily cleaved by proteases, it will be more pathogenic.”

Wildlife Health Australia noted that while the high pathogenicity avian influenza (HPAI) strains have been affecting poultry in Australia, it has yet to affect wild birds.

Historically, Australia has experienced 10 outbreaks of the H7 strains.

“HPAI has never been detected in Australian wild birds, other than one detection of HPAI H7 in a feral Eurasian starling (Sterna vulgaris) trapped inside an affected poultry shed during a 1985 HPAI outbreak,” the organisation said (pdf).