The One Health Poultry Hub and its partners are continuing to closely monitor the spread of high pathogenic avian influenza (HPAI) (also known as ‘bird flu’) across a large swathe of the world, which is now having a devastating impact on poultry production and health along with food security. The virus’s spread and widespread distribution also remains an ever-present threat to global public health.
The situation is dynamic with the epidemic affecting a large area from Southeast Asia, across central and South Asia and into the Middle East and Europe. There is also a resurgence in Africa, particularly West Africa. A first case has recently been recorded in North America, only the second time this group of highly pathogenic viruses have reached that continent.
The avian influenza virus is continually evolving and being spread across a large area by migratory birds but also importantly between sites where poultry are kept, including farms and live bird markets. This emphasises the importance of the critical surveillance that’s been established in the Hub, using relevant diagnostics, and highlights the need for timely analysis.
Partners in the Hub are continuing to work very closely at an international scale to track the current disease threat from the H5 strains in circulation, in particular a group belonging to the clade 18.104.22.168b, to include H5N1, H5N6 and H5N8 subtypes. In principle these strains are considered to have low risk for public health, but vigilance is urged. Human infections have been reported in China, Russia and West Africa and a cautionary approach should be taken.
It is clear from these emerging events that the global threat from HPAI has increased dramatically. The disease is enzootic (regularly affecting birds in a defined area or season) in many countries, including in Bangladesh and Vietnam, where the One Health Poultry Hub is working, and occurring annually in others that have been traditionally free, including in the UK.
International relationships, including through OFFLU and actively involving partners in the One Health Poultry Hub, are seeking to monitor virus emergence and spread. However, there are many gaps in our knowledge that detract from the ability to map and understand what is going on in its entirety, including drivers of virus change. Substantial further investment in this work is required.
There are key gaps in knowledge in relation to the drivers of avian influenza virus emergence, in particular of the virus pool in wild birds and poultry. Whilst poultry vaccination will have an important role for global control, coherent systems and structures for rapidly tracking and monitoring the virus need to be developed to ensure globally relevant solutions.
We need a regional and global blueprint for making the best use of new technology to match avian influenza vaccines to virus strains circulating at any one time – much like the effort currently underway with COVID-19 vaccine development. Until that is in place, effective mitigation and control options are more limited and the critical outbreak situation continues.
However, while wild birds are known to be a key mechanism for spreading avian influenza viruses, many other factors, including people’s behaviour and cultural practices, are known to contribute to virus emergence, persistence and spread. We need more investment in research into this too. Control is not just about vaccination – but also about understanding behaviour and what may be influencing it.
Understandably, in the midst of a major human health crisis with the COVID-19 pandemic ongoing, there is a risk that attention is diverted from avian influenza. Current events though underline the importance of continuing investment and global partnerships in avian influenza – including greater understanding of the ever-present threat it presents to public health worldwide.
Professor Ian Brown is Director, and Professor Nicola Lewis is Deputy Director, of the OIE/FAO International Reference Laboratory for avian influenza, swine influenza and Newcastle disease. In addition, Professor Brown is Chair of the OFFLU steering committee and Professor Lewis OFFLU technical activity lead for WHO vaccine composition.