First human case of H5N1 avian influenza in Australia, H7N9 bird flu on Terang farm
Human H5N1 avian influenza
Victoria Health Chief Health Officer, Dr. Clare Looker issued a health advisory this week due to a case of avian influenza A (H5N1) infection, also known as “bird flu”, reported in the state.
The case occurred in a child, who acquired the infection in India and was unwell in March 2024. The avian influenza virus was detected through further testing of positive influenza samples that takes place to detect novel or concerning flu virus strains, as part of Victoria’s enhanced surveillance system. Contact tracing has not identified any further cases of avian influenza connected to this case.
India has recently reported outbreaks with HPAI A(H5N1) in poultry in various states.
This is the first human case of H5N1 avian influenza in Australia.
The Department of Health is supporting Agriculture Victoria in responding to an outbreak of avian influenza among birds at a poultry farm in regional Victorian. Testing has confirmed this outbreak is not related to this human case.
The transmission of avian influenza from birds or animals to humans is very rare. Most people are not at risk, unless they have contact with infected birds or animals, or their secretions, while in affected areas of the world. Rarely, avian influenza infection in humans can pass to another person with prolonged contact.
The symptoms of H5N1 infection may include fever, cough, headache, aching muscles and respiratory symptoms. Other early symptoms may include conjunctivitis and gastrointestinal symptoms. The infection may progress quickly to severe respiratory illness and neurological changes.
CDC Yellow Book 2024: Health Information for International Travel
Globally, since 2003 and as of 22 May 2024, there have been 891 human cases, including 463 deaths (CFR: 52%), with avian influenza A(H5N1) infection reported in 24 countries. To date, no sustained human-to-human transmission has been detected. In 2024, ten cases, including two deaths, have been reported in four countries, Cambodia (five cases, one death), US (two cases- Texas and Michigan), Vietnam (two cases, one death) and Australia (one case).
Avian influenza in Victoria
On Friday, Agriculture Victoria reported responding to the detection of avian influenza at two 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 H7N9.
These properties have been placed in quarantine and all poultry will be safely disposed of and the sites cleared of the infection.
Diagnostic testing has confirmed the H7N9 avian influenza strain at the infected property at Terang. As a result, the restricted area has been increased to a 5 km radius around the infected property. Updated Movement Controls can be found below.
Movement controls are now in place to prevent any spread of avian influenza.
Subscribe to Outbreak News TV on YouTube
This includes:
a restricted area covers a 5 km radius around the Meredith farm with a broader Control Area buffer zone in the eastern part of Golden Plains Shire Council. The western boundary of this area is the Colac-Ballarat Road.
a restricted area covering a 5 km radius around the Terang farm with a broader control Area buffer zone covering a 15 km radius.
a housing requirement for all birds within these areas.
Avian influenza, commonly referred to as ‘bird flu,' is a highly contagious viral infection of birds. Serious forms of the disease caused by highly pathogenic avian influenza (HPAI) viruses can result in severe symptoms and sudden death in domestic poultry (up to 100% of birds). Mild strains forms of the disease caused by low pathogenic avian influenza (LPAI) viruses cause few or no symptoms in poultry and may go undetected in some species of birds, though can result in some deaths.
Avian influenza viruses are complex and are classified into subtypes based on 2 surface proteins, the haemagglutinin (HA) and neuraminidase (NA). For example, a virus that has HA 3 protein and NA 2 protein is designated as subtype H3N2. At least 16 haemagglutinins (H1 to H16), and 9 neuraminidases (N1 to N9) subtypes have been found in viruses from birds. Some specific LPAI virus subtypes (subtypes H5 and H7) can evolve to HPAI virus following spillover from wild birds and circulation in poultry.
H5N1 is a subtype of HPAI which is causes serious disease in poultry, wild birds and some species of wild mammals globally. It has not been detected in birds in Australia to date.