Bird flu arrives in Australia - Expert Reaction

Two bird flu incursions have hit the Australian state of Victoria.

Avian influenza has been detected on an egg farm in Victoria’s west, however it has been identified as the H7N3 strain of the virus, not the H5N1 variant which is causing concern overseas.

Meanwhile a child returning to Victoria from overseas has tested positive for the H5N1 bird flu strain.

The SMC asked experts to comment.

Professor Jemma Geoghegan, Virologist, University of Otago, comments:

“The child who travelled from India to Australia in March 2024 was diagnosed with the Highly Pathogenic Avian Influenza virus H5N1. Although this virus is the H5N1 subtype, its genomics tell us it is not related to the specific genetic clade that has spread rapidly in recent years around the world. It is also worth stressing that the virus does not yet spread easily between people and is very much still adapted to avian hosts. There is no evidence of ongoing transmission from this case.

“This human case, along with a different strain found in chickens in Victoria, highlights the importance of rapid testing and genomic sequencing to better understand the risk to animal and human health. As we found during the COVID-19 pandemic, testing and genomics can help us better inform our response and it is vital that New Zealand is well prepared in this space.”

No conflicts of interest declared.

Distinguished Professor Nigel French, Massey University; and Chief Science Advisor, Te Niwha, comments:

“These two incidents underline the importance of preparedness for an incursion of avian influenza into Aotearoa. Bird flu requires a coordinated ‘One Health’ multi-agency approach to surveillance and response, given its importance to wildlife and domestic animals, and the potential for it to spillover and cause severe disease in humans.

“Despite these two reports from Australia, Oceania remains the only continent free of the strain of highly pathogenic avian influenza (HPAI bird flu) that is sweeping the world, causing large-scale mortality events in wildlife and poultry, and outbreaks of disease in cattle in the United States. The strain of concern globally is a variant of H5N1 (called 2.3.4.4b), whereas the egg farm in Australia is affected by another strain of avian influenza, identified as H7N3 by Agriculture Victoria. This is the second time an outbreak of a strain of avian influenza has emerged in Australian egg producers in the last few years, the last being an outbreak of H7N7 in 2020.

“The human case in Australia was a traveller from a country where H5N1 is circulating. No other cases have been identified through contact tracing, and although they developed severe symptoms, they have since recovered. This is a common scenario for human cases of bird flu – sporadic, severe infections with no evidence of sustained transmission.

“Aotearoa’s Health agencies, the Ministry for Primary Industries, the Department of Conservation, iwi, community groups and the farming sector are working together to ensure any incursion of bird flu is detected early and an appropriate response instigated. This includes the H5N1 strain of global concern, and all other avian influenza viruses, including H7N3. The public are also encouraged to help with surveillance by familiarising themselves with the signs to look out for, particularly in wildlife, and what to do to report anything that looks suspicious of bird flu. Comprehensive information on what to look for and how to respond is here.

“Science is playing an important role in Aotearoa’s preparedness. The Infectious Disease Research Platform, Te Niwha, is funding a project carried out by the University of Otago and ESR to develop environmental monitoring for bird flu in wildlife, and the Department of Conservation is trialling vaccination of endangered taonga wild birds.”

No conflict of interest.

Dr Sarah Jefferies, Public Health Physician, Health Intelligence and Surveillance Group, ESR, comments:

“New Zealand has laboratory capability to detect the three major HA-types (haemagglutinin antigen types) of highly pathogenic avian influenza (HPAI) currently circulating globally (H5, H7 and H9) including the two types recently detected in Australia. HPAI is a notifiable disease in New Zealand under the Health Act with national guidance for suspected case notification and a direct laboratory notification pathway.

“For comment on animal surveillance, please contact MPI.

“In New Zealand, the risk to public health of communicable disease threats is assessed by ESR’s Health Intelligence and Surveillance team. ESR reviews and updates the HPAI human health risk assessment when there is a change in the behaviour of the virus such as increasing detections overseas or in other animals. ESR is currently updating their assessment in liaison with key technical counterparts. This is as a result of the recent detection of HPAI in dairy cattle in the United States, and identification of the imported human case of a different strain and unrelated poultry farm avian influenza reported in the past 24 hours by Australia.

“However, ESR advises that the previously reported overall low HPAI public health risk assessment for New Zealand is unlikely to substantively change based on the intelligence around these events to date. Human cases of HPAI are currently rare events, with a very low risk of importation of human HPAI cases to New Zealand. Most of the current risk of transmission to humans overseas is associated with unprotected close contact with infected poultry or dairy cattle. The currently known HPAI viruses are not capable of sustained person-to-person transmission. This does not preclude the ongoing and critical need to continue current preparedness activities which are currently being led in a multi-disciplinary approach by MPI, MoH, Health New Zealand and the DOC.”