Everything you need to know about the new Victorian bird flu outbreak

A new strain of bird flu has been found in northern Victoria, forcing a chicken farm into lockdown and causing concern for the state’s biosecurity authorities.

Agriculture Victoria said that after a score of unexplained bird deaths at the commercial chicken farm early last week testing found the birds were carrying the highly pathogenic H7N8 strain of avian influenza.

Workers prepare to kill chickens after an avian flu outbreak near the town of Meredith last May.Credit: Jason South

The eastern two-thirds of Strathbogie Shire have become a controlled area – meaning farms in the region are being monitored to ensure the virus does not spread.

What do we know about this new strain?

Different strains of avian influenza are categorised as either having a low or high pathogenic level. The H7N8 strain detected in Euroa, about 162 kilometres north of Melbourne, is considered highly pathogenic, meaning it is capable of causing significant symptoms and disease.

Bird flu is generally highly infectious. Symptomatic birds shed the virus in their saliva, nasal discharge and faeces. It can infect many different types of birds, including chickens, ducks, geese, emus, waterfowl and seabirds.

Although a 2024 outbreak in NSW and ACT was also a H7N8 virus, laboratory results have shown the current Victorian outbreak is a different strain. As of Sunday, the strain has been found at just one poultry farm in Victoria.

How did it spread to the Euroa farm?

Victorian authorities believe wild birds carrying the strain could have given the disease to the chickens in Euroa. The virus can make the jump into poultry when there is direct contact with infected birds, or when wild birds – such as migratory ducks and geese – contaminate domestic flocks’ food or water.

Biosecurity authorities say they are keeping an open mind when it comes to the source of the current Victorian outbreak.

Internationally, predatory and scavenger bird species have also caught different strains of avian influenza when consuming infected bird carcasses.

What has happened during other outbreaks of avian flu?

Sixteen farms across Victoria, NSW and the ACT were affected by different H7 variants last year, leading to the culling of more than 2 million birds.

In May, a farm in the small Victorian town of Meredith, west of Melbourne, discovered its chickens were infected with the H7N3 flu strain. At the same time, a slightly different variant (H7N9) had taken off in a farm in Terang in Victoria’s south-west.

Thousands of culled chickens in a truck after last year’s Meredith outbreak. Credit: Jason South

The strain of concern circulating worldwide – H5N1 – has killed more than 130 million wild and domestic birds. In January, the first human death from H5N1 in the US was recorded. Nearly 70 people in the US, mostly farmworkers, have contracted bird flu since April, the Centres for Disease Control and Prevention says.

H5N1 has also made the jump into other mammals, killing more than 30,000 sea lions and 18,000 southern elephant seal pups in South America since 2022.

Between 1976 and 2021, there were nine outbreaks of highly pathogenic bird flu on poultry farms in Australia.

Is it dangerous to humans?

While there have been cases of humans in direct contact with animals getting infected with highly pathogenic varieties of bird flu, Agriculture Victoria says the current risk to the public remains low.

Vaccines for certain bird flu strains are available. Poultry workers in outbreak hotspots prioritised for inoculation. Eggs and poultry products remain safe to eat.

Will there be any eggs on supermarket shelves?

Victoria’s acting chief veterinarian, Dr Cameron Bell, said the current outbreak was not expected to lead to a huge drop in egg supply.

“Some large egg farms were impacted during last year’s event, and it is disappointing to be in this position again,” he said.

“Fortunately though, this time the farm is not one of our larger egg production facilities, so we expect the impacts on supply from this event will be less.”

What symptoms does it cause, and what can the government do about it?

Birds with the virus can have classic flu symptoms such as sneezing, coughing, difficulty breathing and malaise. The flu also causes head swelling and sudden death in birds.

Biosecurity experts often have to euthanise scores of infected poultry and other birds in contact with the ill population during an outbreak.

Strict quarantine measures controlling the movement of poultry around affected farms are put in place, and farms have to be decontaminated after bird flu is discovered.

In Euroa, a five-kilometre restricted zone has been created.

“There’s quite a process,” Bell told a press conference on Sunday.

“In terms of the on-farm activity, we’re talking weeks to months here in terms of how long it will take to do that initial disposal of birds, the cleansing and then ultimately verifying the property is free of avian influenza.”

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