Australia: 3rd Victoria Poultry Farm Hit With HPAI H7N3

Victoria : Credit Wikipedia

 #18,098

Twelve days ago we learned about Two Outbreaks of H7N3 In Victoria, on farms roughly 70 miles apart (Meredith and Terang). While Agriculture Victoria has not released exact numbers, the Australian Broadcasting System reported `hundreds of thousands' of birds have been culled.

While H7 outbreaks (both LPAI & HPAI) are generally regarded as less serious than H5 - the 5 year reign of H7N9 in China (2013-2018) showed what an H7 virus was capable of; infecting more than 1,500 people and killing roughly 40% of them.

H7N9 Epidemic Waves - June 14th 2017 - Credit FAO

China's H7N9 was admittedly an outlier, with most human infections with H7 producing only mild illness.  A few examples include:

• In 2018 a woman in Jiangsu Province, China was seriously infected by an H7N4 virus (see WHO Update & Risk Assessment On Avian H7N4), spending 21 days in the hospital
• NYC's 016 dramatic H7N2 outbreak in cats, and spillover into animal shelter workers (see J Infect Dis: Serological Evidence Of H7N2 Infection Among Animal Shelter Workers, NYC 2016)
• 3 mild cases of LPAI H7N7 in Italy in 2013 (see ECDC Update & Assessment: Human Infection By Avian H7N7 In Italy).
• In 2006 1 person in the UK was confirmed to have contracted H7N3, and the following year, 4 people tested positive for H7N2 – both following local outbreaks in poultry.
• The Fraser Valley H7N3 outbreak of 2004 resulted in at least two human infections, as reported in this EID Journal report: Human Illness from Avian Influenza H7N3, British Columbia.
• And in 2003 a large outbreak of H7N7 (89 confirmed, 1 fatality) in the Netherlands – with nearly all reported cases having very mild (often just conjunctivitis) symptoms.

Today Agriculture Victoria has announced a 3rd farm - the second in the Meredith area - has tested positive for HPAI H7N3.

Current situation

Last updated 04 Jun 2024 11:08am

We are responding to the detection of avian influenza at 3 Victorian poultry farms.

The first infected property near Meredith is confirmed to have the H7N3 strain of avian influenza and the second infected property near Terang is confirmed to have the H7N9 strain. One additional property in the Meredith area has now been confirmed as an infected property.

This new infected property is located within the current 5 km Restricted Area  in the Golden Plains Shire. Tests have now confirmed the high pathogenicity H7N3 strain of the avian influenza virus at the property.

This property has been placed in quarantine and all poultry will be safely disposed of. The sites will be cleaned and cleared of the infection.

Housing requirement

We have issued movement controls that include a housing requirement for all birds within the Restricted Areas and Control Areas in Meredith and Terang.

Under the housing requirement all poultry farmers, backyard flock and bird owners must house or keep their birds enclosed in cages or sheds as much as practical.

Agriculture Victoria staff are on the ground supporting the businesses and working closely with industry to contain and eradicate the virus. Contact tracing is also underway to determine the source and spread of the infection.

Avian influenza is a viral disease of birds found globally. Virus strains are described as low pathogenicity (LPAI) or high pathogenicity (HPAI).

Poultry farmers, backyard flock and bird owners are urged to report any cases of unexplained bird deaths to the VicEmergency Hotline on 1800 226 226.

While cases among humans in direct contact with animals infected with highly pathogenic 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.

         (Continue . . . )

While Australia/NZ/Oceania remain free from HPAI H5N1, like everywhere else, LPAI viruses circulate in local birds.  Most are considered innocuous to poultry and humans, but when an H5 or H7 LPAI virus spreads among poultry for an extended period of time, it can sometimes spontaneously mutate into an HPAI strain. 

While most of these HPAI outbreaks will be limited to a single farm, the virus can be inadvertently spread by moving birds, eggs, feed, equipment or personnel between farms - and less commonly - by local or migratory birds which may pick it up and carry it some distance. 

Hence the OIE/WOAH requirements to report, and quickly eradicate, all H5 and H7 outbreaks in poultry. 

Victoria Agriculture also provides the following advice: 

Spread to humans

The spread of avian influenza from birds to people is rare but may occur with some strains of the virus if there is close contact with infected birds or their droppings, or with heavily contaminated environments. Always practice good personal hygiene when handling birds.

People cannot become infected by consuming cooked chicken meat or eggs.

If you have had contact with birds on an affected property and you are experiencing cold or flu symptoms, call your doctor or the Department of Health on 1300 651 160 for medical advice.

Find out more about avian influenza in humans from the BetterHealth Channel.

Risk to Australia

Ongoing outbreaks of H5N1 globally have increased the level of risk to Australia for incursions of HPAI viruses of global concern. Occasional outbreaks of internationally notifiable highly pathogenic avian influenza (non-H5N1) and of low pathogenicity avian influenza have occurred on poultry farms in Australia.

Each outbreak was quickly detected and eradicated, with only a small number of farms affected.

Annual migration of wild birds has the ongoing potential to introduce new subtypes of avian influenza virus to Australian birds.