After a series of localized outbreaks in recent years, bird flu has re-emerged as one of the biggest killers of birds in the UK. Until recent weeks, the latest outbreak of the disease – also known as bird flu or, to scientists, highly pathogenic avian influenza – was primarily treated as a problem for chickens and other domestic birds. It triggered localized responses such as culling, and farmers were ordered to keep animals indoors for six months over winter, which is why the UK has had a period without bred eggs freely.
But reports of large numbers of wild seabirds being found dead in Scotland, and increasingly in England and Wales, suggest bird flu is now widespread among wild birds across much of the world. northern Britain. I myself have encountered a number of these birds on the Northumberland coast.
Scenes like these will make the crisis much more visible to the general public, and naturally they will ask what more we can do to fight the epidemic.
The 2021-22 avian flu epidemic
The 2021-22 outbreak is a global problem, with cases of the virulent H5N1 subtype detected in West Africa, Asia, and nearly every country in Europe and North America. It is primarily a disease of domestic birds, where it is believed to have originated, and has led to the culling of hundreds of millions of birds, including 38 million in the United States this year only.
In the UK, the disease was first detected in October 2021. As elsewhere, the outbreak was initially largely confined to poultry, and farmers were forced to cull 500,000 chickens and other birds. In response, the UK has established an avian flu prevention zone comprising 10km buffer zones around detected cases, with restrictions on bird movements and enhanced biosecurity.
During the winter, a number of wild bird populations were reported to be affected by avian influenza, including the great skua, pink-footed goose and barnacle goose. These included the mass death of 4,000 birds in the Solway Firth, representing a third of the Svalbard barnacle goose population that winters in the area.
As spring has become summer, there is no longer any doubt that bird flu is now spreading to a greater diversity of wild birds in the UK. For some species, this probably reflects their return to summer breeding colonies, and the increased mixing that this entails (bird flu is transmitted through contact with saliva or feces).
As this breeding season reaches its peak, a wide range of seabirds have been affected, including great skuas, common eiders, fulmars, terns, gannets and guillemots. The UK holds over half of the world’s population of northern gannets and great skuas, both of which have been officially recognized as birds of moderate conservation concern (‘amber status’). Bird flu adds to the litany of problems facing these birds – from climate change to entanglement in derelict fishing gear – and heightens the concerns of organizations such as RSPB and Birdlife, who already view this outbreak as the worst the UK has ever seen.
More resources needed
Conservation organizations have asked for more resources to help monitor and fix the problem. Many ornithologists and reserve managers already work in the nature reserves most affected by bird flu, and so they will be an important part of the solution. We could also reduce the level of human disturbance at particularly sensitive sites, for example by introducing buffer zones or seasonal restrictions.
But, more broadly, we just need more bird flu surveillance to get a better idea of the problem. It will also mean giving relevant government departments and agencies the resources they need to monitor and test more wild birds.
In summer, bird flu retains infectivity in the environment for up to 18 days. Thus, the large number of dead birds on the coast with possible infections presents a continuing route of transmission to birds of prey and scavengers, especially gulls, which are known to be susceptible to avian influenza. Increasing the number of carcasses collected would have the added benefit of eliminating the risk of infecting scavengers, and thus infecting more other birds.
Given that some of these seabirds can travel great distances in search of food – up to 400 km for northern gannets, for example – we will need a national approach in this regard, with coordination between the four nations of the United Kingdom. And because the virus has been transmitted repeatedly between domestic stocks and wild bird populations, we should also review biosecurity measures in the poultry industry.
What does this mean for the general public? Although avian influenza is a zoonotic disease like COVID-19, the risk to human health is very low and cases in humans are almost exclusively due to close contact between bird farmers and their livestock. The advice to the public is not to touch any dead birds you see and report them.
If you feed wild birds, consider washing and disinfecting feeders weekly and cleaning birdbaths daily, as bird flu is transmitted primarily through saliva and droppings. And if you’re walking the dog, watch him more closely when you’re on the beach or by the water, and use a leash when you’re in a nature reserve or see a dead bird.
There is no doubt that the increased visibility of deaths will make the general public aware of the extent of the problem. Avian flu has now “come” to our minds and will gain prominence as summer wears on and holidays begin. Although the risk to humans is very low, it reminds us of how connected we are to nature and how our interactions with the natural world have huge consequences on what we think of as “human” systems.
Andrew Suggitt, Vice-Chancellor’s Senior Researcher, University of Northumbria, Newcastle
This article is republished from The Conversation under a Creative Commons license. Read the original article.