PHOTO: Colorized transmission electron micrograph of Avian influenza A H5N1 viruses (seen in gold) grown in MDCK cells (seen in green). Public domain.

Deadly bird flu outbreaks are starting in new places – Expert Reaction

Deadly bird flu virus outbreaks are now starting in places outside Asia, including in Europe and Africa, suggesting a shift in the global distribution of the viruses, according to new international research.

The deadly H5N1 virus first emerged in China in 1996 but it is now infecting and killing increasing numbers of wild birds and poultry, as well as posing a risk to humans. Since 2014, there have been several outbreaks of similar bird flu viruses in the H5 group, and the research found that while 2016/17 outbreaks started in China, two new H5 group viruses emerged from African and European countries – suggesting a shift of the H5 epicentre away from Asia. The authors suggest that the increasing persistence of bird flu in wild bird populations is driving the evolution and spread of new strains.

The SMC has asked local experts to comment on the overseas research. Additional comments by Australian experts are available on Scimex.

Nigel French, Distinguished Professor of Infectious Disease Epidemiology and Public Health, Massey University, comments:

“Devastating bird flu viruses are circulating between domestic animals and wildlife, and recent trends show an alarming increase in mortality, particularly among wild birds and poultry. These viruses also cause incidental infections in mammals, including humans.

“This study provides a unique insight into how these viruses have evolved and why they have emerged and expanded their host and geographical ranges; affecting multiple species across Europe, Asia, Africa and the Americas. This work utilised genome sequence and epidemiological data to infer patterns of evolution, changes in virulence, and the origins and geographical spread of these viruses.

“However, the authors acknowledge the limitations and gaps in available genomic surveillance data, underlining the need to expand global surveillance to include a wider range of host species and locations. If surveillance, prevention, and control measures are not adequately planned for and implemented, the risk of a pandemic that has a significant impact on both human and animal health is greatly increased.

“Aotearoa New Zealand has not seen an outbreak of highly pathogenic avian influenza to date, but given the rapid changes in the evolution and spread of these viruses we can’t be complacent. With such a rapidly changing global situation, we need to ensure our surveillance systems remain sufficiently sensitive to detect these viruses should they arrive on our shores.”

No conflicts of interest declared.

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

“This paper demonstrates that virus genetic changes have resulted in both a geographic and host range expansion of highly pathogenic avian influenza virus over recent years.

“These findings highlight the importance of flexibility in our passive and active surveillance regimes here in Aotearoa New Zealand. We need to remain on high alert to these threats and be quick to adapt as new findings, such as these, come to light.

“The article also emphasises the importance of generating viral genetic data to inform such outbreaks – something that we learnt well during the COVID-19 pandemic and something that we can easily do in New Zealand.”

No conflicts of interest declared.

Ruy Jauregui, Principal Scientist, Bioinformatics, Biosecurity New Zealand, comments:

“It always strikes me in wonder how, while being such simple organisms, viruses display such extraordinary complexity. Great havoc in a small package, I think. Reading this research, we become aware that human activity has a wide-reaching impact in unsuspecting ways. The avian influenza virus finds, due to global farming practices, an incredible reservoir to mutate and reassort in our poultry and waterfowl flocks, and now it comes to lay pressure in the spot where our domesticated birds interact with wild ones, who disperse these new mutants far and wide. Flu viruses are a fast-evolving moving target, and only attentive surveillance will allow us to keep track with what new strategies they come up with.”

No conflict of interest.

Dr Mary van Andel, Chief Veterinary Officer, Ministry for Primary Industries, comments:

“This recent paper highlights and provides more information, about how the host range, and distribution of H5N1 has changed. It provides the genomic basis and more information for the reason why the solutions for managing HPAI need to evolve and adjust as the virus does. This can only happen if these viruses are closely monitored. This paper, and other emerging research, are essential for New Zealand’s ongoing preparedness for HPA. That preparedness work is well underway.”

No conflict of interest.