An outbreak of H7N7 high pathogenicity avian influenza in Victoria, Australia, in 2020

On 31 July 2020, an outbreak of H7N7 high pathogenicity avian influenza (HPAI) was confirmed on a free-range, egg-producing poultry farm in the Lethbridge area of southwest Victoria. The property was immediately quarantined, and an emergency animal disease response plan was prepared to guide containment, and then eradication, of the disease in accordance with the Australian Veterinary Emergency Plan (AUSVETPLAN) and to meet the requirements of the Australian Emergency Animal Disease Response Agreement (EADRA). Birds on two additional premises were subsequently confirmed as infected with H7N7 HPAI. Extensive surveillance undertaken during the response also identified infection with low pathogenicity avian influenza on three further properties-two commercial turkey properties (H5N2 subtype) and one emu farm (H7N6 subtype). These properties were also subjected to disease eradication procedures. Humane destruction of birds on all affected properties was completed by 8 September 2020. Cleaning and decontamination activities were completed on all sites by 11 December 2020. Extensive tracing and surveillance activities did not identify any further cases of H7N7 HPAI in domestic or wild birds. In terms of both numbers of birds and impacted properties, this was the largest outbreak of HPAI recorded in Australia up to that time. On 26 February 2021, Australia's Chief Veterinary Officer declared that the country had regained freedom from HPAI in accordance with international standards published by the World Organisation for Animal Health (then the OIE).