Australia: Victoria Reports A New Outbreak of HPAI (H7N8) - 3rd Outbreak Feb 20th

[Michael Coston]

Australia: Victoria Reports A New Outbreak of HPAI (H7N8)​

Outbreaks of H7 avian flu in 2024

#18,608

While Australia/NZ/Oceania remain free from the HPAI H5N1 virus, last year Australia's poultry industry was rocked by repeated outbreaks from 3 different subtypes of H7 avian flu (see map above). Just over 2 months ago, New Zealand reported their first outbreak (of H7N6).

LPAI (low path) viruses circulate worldwide. Most are considered innocuous to poultry and to humans, but when an H5 or H7 LPAI virus spills over from wild birds into poultry they can sometimes spontaneously mutate into an HPAI strain.​

After a long struggle, 5 days ago Australia's poultry industry declared themselves free of the H7 virus (see statement below):

Current situation

On 3 February 2025, Australia self-declared freedom from high pathogenicity avian influenza (HPAI) H7 to the World Organisation for Animal Health, effective 23 January 2025.

HPAI H7 has been eradicated from Victoria, NSW and the ACT and there have been no new detections of HPAI H7 in Australia since 12 July 2024.

In 2024, a response to three strains of HPAI H7 took place. There were 16 infected premises including 8 in Victoria, 6 in NSW and 2 in the ACT.​

But, as we've seen so many times in the past, such declarations are often fleeting. LPAI and HPAI viruses abound in nature, and new subtypes (and genotypes within subtypes) are emerging all of the time.


Today Victoria is reporting a fresh outbreak - this time of HPAI H7N8 - which is different from the two strains they reported in 2024. First their statement, after which I'll have more on H7 viruses.

Current situation

Last updated 8 February 2025

Agriculture Victoria has confirmed the presence of avian influenza at a poultry property in northern Victoria, which has now been placed into quarantine.

Diagnostic testing performed by Australian Centre for Disease Preparedness at Geelong confirmed high pathogenicity H7N8, which is different to the strain that impacted Victorian poultry farms during 2024. Although the 2024 New South Wales/Australian Capital Territory outbreak was also an H7N8 virus, the current laboratory has advised that the current Victorian outbreak is a different virus.

The property has been placed under quarantine and a declared area is in place in the eastern two-thirds of the Strathbogie Shire to prevent movements that could spread the virus. Any suspicion of an emergency animal disease (EAD) should be immediately reported to the 24-hour EAD Hotline on 1800 675 888 or to your local vet.

Consumers should not be concerned about eggs and poultry products from the supermarkets, they do not pose a risk and are safe to consume.

While cases among humans in direct contact with animals infected with high pathogenicity avian influenza viruses are possible, the current risk to the public remains low. Find out more about avian influenza in humans from the BetterHealth Channel.

In 2024 Victoria experienced Australia’s largest avian influenza outbreak on record.

Between 22 May and 24 June, 8 properties tested positive for high-pathogenicity H7N3 and H7N9 avian influenza in south-west Victoria.​

HPAI H7 viruses remain primarily a concern for poultry producers, with human infections up until 2013 being both rare and generally mild. But in 2013 an LPAI H7N9 virus emerged in China in 2013 which showed us that - with the right set of mutations - an H7 virus can become a formidable public health threat.

H7N9 Epidemic Waves - June 14th 2017 - Credit FAO

Luckily, that deadly strain has gone to ground since China's introductions of an H5+H7 vaccine in 2017 - and while versions of it still circulate in birds - it appears to have lost much of its affinity for mammals (see EID Journal: Evolution and Antigenic Drift of Influenza A (H7N9) Viruses, China, 2017–2019).

For now, the H7 viruses popping up in Australia show no signs of posing any kind of serious public health threat.​

But, as with all influenza viruses with zoonotic potential, things can change over time. Which is why these outbreaks must be quickly contained, before something worse can happen.​


https://afludiary.blogspot.com/2025/02/australia-victoria-reports-new-outbreak.html

 

[Michael Coston]

Australia: Victoria Reports 3rd Outbreak Of HPAI H7N8

Outbreaks of H7 avian flu in 2024

#18,633

Just days after declaring their 2024 outbreak over (see map above), on February 8th Victoria Reports A New Outbreak of HPAI (H7N8) - which is different from the two HPAI H7 strains they reported in 2024.

A week later (Feb 13th), Victoria announced a 2nd Poultry Victoria Poultry Farm with HPAI H7N8, and today they announce a 3rd.​

First today's announcement, after which I'll have more on the debate over culling infected poultry.

Current situation

Last updated 20 February 2025

H7 avian influenza (bird flu) is confirmed at a third poultry property in northern Victoria. All infected properties are within the control area and under quarantine.

Given the close proximity to existing infected properties, this new detection is not unexpected.

Diagnostic tests confirmed a high pathogenicity strain of H7N8. The tests were done at CSIRO’s Australian Centre for Disease Preparedness in Geelong.

This is a new outbreak and not related to the 2024 outbreaks in Victoria, New South Wales and the Australian Capital Territory. The past outbreak was successfully eradicated.

This is not the H5N1 bird flu strain that is impacting other parts of the world.

A restricted area with a radius of about 5 km is in place around the infected properties. This is part of a larger control area in Strathbogie Shire, east of the Goulburn Valley Freeway. The goal is to prevent movements that could spread the virus.

Townships impacted include:

• Euroa
• Violet Town
• Longwood
• Ruffy
• Avenel
• Strathbogie.

The control and restricted areas have specific rules.

Producers with 50 or more birds including poultry need to follow a housing requirement.

Any suspicion of an emergency animal disease (EAD) should be immediately reported to the 24-hour EAD Hotline on 1800 675 888 or to your local vet.

Agriculture Victoria is actively working with property owners. The first 2 infected properties have finished humane destruction of poultry on site. Work will start at the new property soon.

Cases of humans in direct contact with animals infected with high pathogenicity avian influenza viruses are possible. However, the risk to the public is low. Find out more about avian influenza in humans from the BetterHealth Channel.​

What we are witnessing (repeatedly) in Australia (and in other countries) is the birth of new subtypes and genotypes of HPAI viruses in poultry. While H7 viruses are viewed as slightly less dangerous than H5 viruses, the experiences with H7N9 in China and H7N7 in the Netherlands are not to be ignored.

Simply put, LPAI (Low path) H7 or H5 viruses - which are ubiquitous in wild birds - make their way into a poultry flock, where they spread, evolve, and sometimes spontaneously mutate into highly pathogenic (HPAI).
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We've seen this happen repeatedly around the globe, including here in the United States (see map below). If left unchecked, one or more of these viral incarnations could eventually become a legitimate rival to H5N1.


Outbreaks In March 2017

Which is why even LPAI H5 and H7 outbreaks are viewed as dangerous - and immediate culling is the standard procedure - even though they may produce low mortality in poultry. Allowing the virus to `run its course' - as many are currently suggesting - is the equivalent of running a Gain of Function study in a basement laboratory with little or no biosecurity

We've already seen (admittedly, controversial) evidence that HPAI viruses may be carried for miles from infected farms by the wind. Even without that - quarantines are never 100% effective - which suggests the longer an infected flock is allowed to remain in place, the greater the chances the virus will spread.​

Although there may be a legitimate role for the use of poultry vaccines to protect flocks, their use in other countries hasn't always produced the desired results (see Vaccines: Vaccination and Antiviral Treatment against Avian Influenza H5Nx Viruses (Review Article)).

While culling is a horrible solution, good alternatives are in short supply.

https://afludiary.blogspot.com/2025/02/australia-victoria-reports-3rd-outbreak.html
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