Thursday, February 20, 2025

Australia: Victoria Reports 3rd Outbreak Of HPAI H7N8

 

Outbreaks of H7 avian flu in 2024

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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). 

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.


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.  
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