Outbreaks of avian influenza
Avian influenza viruses are restricted and prohibited matter under the Biosecurity Act 2014.
Large outbreaks of highly pathogenic avian influenza (HPAI) overseas have been causing significant mortalities in poultry and wild bird populations in recent years.
The overall risk of HPAI being introduced to Australia through migratory birds’ annual flight paths has been considered to be low; however the current global situation means the risk is now considered higher than in previous years. The period of greatest concern is September to November, when migratory birds return from the northern hemisphere to Australia.
Queensland bird owners are reminded to have good biosecurity measures in place at all times to reduce the risk of diseases being introduced or spread.
If you suspect avian influenza in birds within Queensland, contact us immediately on 13 25 23 (business hours) or the Emergency Animal Disease Watch Hotline on 1800 675 888 (after hours).
Veterinarians can submit suitable samples from birds exhibiting clinical signs suggestive of avian influenza virus infection to the Biosecurity Sciences Laboratory for avian influenza virus testing.
Highly pathogenic avian influenza - HPAI
8 outbreaks of HPAI have occurred in Australia since 1976. HPAI viruses caused clinical disease in commercial poultry in Victoria in 1976 (H7N7), 1985 (H7N7) 1992 (H7N3) and 2020 (H7N7), in Queensland in 1994 (H7N3), and in New South Wales in 1997 (H7N4), 2012 (H7N7) and 2013 (H7N2). Each time, there was severe disease in affected chicken flocks. All had obvious or circumstantial evidence of contact with wild waterfowl or surface water contaminated by wild waterfowl, or with free-range farmed ducks. There is some evidence that, initially, low pathogenicity avian influenza (LPAI) may have been involved in the outbreaks in 1976, 1992 and 1997 (Selleck et al 2003).
In November 2012, an HPAI H7N7 virus was detected in a New South Wales free-range chicken layer flock of 50,000 in the Hunter Valley. The property had a range of dams that attracted wild ducks.
In October 2013, an HPAI H7N2 virus was detected in a free-range and cage bird layer flock of 400,000 near Young.
In July 2020, an HPAI H7N7 virus was detected in three free-range egg farms in Victoria. All three outbreaks were controlled and eradicated, with proof of freedom declared on 26 February 2021.
Low pathogenicity avian influenza (LPAI) (H5/H7)
5 detections of LPAI H5 and H7 virus strains have been recorded in Australian domestic poultry:
- LPAI (H7N7) was isolated on a duck farm during investigation of an HPAI (H7N7) outbreak in chickens in Victoria in 1976. The ducks showed no signs of clinical disease.
- Antibodies to H5, H7 and other subtypes of AI viruses were detected in commercial domestic ducks during investigation of an HPAI (H7N3) outbreak in chickens in Victoria in 1992.
- LPAI (H5) antibodies were detected on a Tasmanian non-commercial, multispecies smallholding in 2006.
- An LPAI (H5N3) virus was detected in a free-range duck flock in Victoria during routine surveillance in 2012. The source of the virus could not be determined, but it is speculated that the primary source may have been wild birds, which were freely able to access the range area.
- LPAI (H5N3) was detected in a duck from a flock of backyard poultry (ducks and chickens) in Western Australia in 2013. This was an incidental finding and all 95 backyard birds were euthanased.
- LPAI(H5N2)was detected attwo turkey farms in Victoria in 2020. LPAI (H7N6) was also detected at an emu farm in Victoria in 2020. All Victorian outbreaks of LPAI were controlled and eradicated, with proof of freedom declared on 26 February 2021.
Low pathogenicity avian influenza (LPAI) (not H5/H7)
The following LPAI (not H5/H7) detections have been made:
- Antibodies to LPAI H1, H4, H5, H7 and H9 subtypes were detected in ducks on a farm in Victoria in 1992.
- LPAI (H4N8) was detected on a multi-age, commercial duck farm in Victoria in 1994.
- LPAI (H6N4) was isolated from a single duck on a property in Queensland in 2006.
- Chickens in several sheds from a property in New South Wales tested seropositive to LPAI (H6N4) in 2006.
- LPAI H10N7 was detected in 2010 in a chicken farm in New South Wales, where transmission to abattoir workers during the processing of the poultry was documented.
- An LPNAI H5N3 virus was detected in a free-range duck flock in Victoria during routine surveillance in 2012. The source of the virus could not been determined, but it is speculated that the primary source may have been wild birds, since wild birds were freely able to access the range area.
- In April 2012, LPAI H9N2 was confirmed on a turkey farm housing about 26,500 turkeys in three sheds near the Hunter Valley in New South Wales; the source of the infection is unknown.
- In 2012, LPAI H4N6 virus was found in ducks of several age groups on a multi-age farm of 2,400 ducks located on the north coast of New South Wales.
- In 2012, an LPAI H10N7 virus was detected in a Queensland poultry flock; the source of the infection is unknown, but it is likely that the primary source may have been wild water birds.