Chicks being swapped to test for avian influenza

Birds across the UK are being tested for avian influenza following over 60 outbreaks across the country. Image © Merrimon Crawford/Shutterstock

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Thousands of birds killed amid 'biggest ever outbreak of bird flu in Britain'

The 'biggest ever outbreak of bird flu in Great Britain' has been blamed for killing thousands of birds in the UK.

Wild and captive birds across the country have died or been killed as a result of the virus, with climate change suggested as having increased the severity of the outbreak. 

A conservation success story on the Scottish and English border has been dealt a major blow in recent months after 4000 barnacle geese died as a result of bird flu.

In the 1940s, just a few hundred of the geese remained in the Solway Firth, but following successful campaigning and changes to the law their numbers increased to over 30,000. Now the Royal Society for the Protection of Birds (RSPB) has said that up to 10% of the geese population have perished amid outbreaks of bird flu across the four nations of the UK.

At the time of writing, over 60 outbreaks have been confirmed across the country as birds migrating into the UK for the winter bring the influenza virus back with them. While the risk to human health is described as 'very low' by the UK Health Security Agency (UKHSA), steps to protect birds are being urged.

The UK's Chief Veterinary Officer, Christine Middlemiss, says, 'We have taken swift action to limit the spread of the disease including introducing housing measures [for domestic birds]. However, we are seeing a growing number of bird flu cases both on commercial farms and in backyard birds right across the country.

'Many poultry keepers have excellent biosecurity standards but the number of cases we are seeing suggests that not enough is being done to keep bird flu out. Whether you keep just a few birds or thousands you must take action now to protect your birds from this highly infectious disease.

'Implementing scrupulous biosecurity has never been more critical. It is your actions that will help keep your birds safe.' 

What is bird flu?

Avian influenza, or bird flu, is one of many strains of the influenza A virus which infect many species of birds. Numerous strains of the virus are relatively harmless to birds, causing mild symptoms such as ruffled feathers or a drop in the numbers of eggs laid.

However, others can be more severe. These pathogens, known as 'high pathogenic avian influenza A viruses' (HPAI), can infect the lungs as well as many other organs of the body, causing serious internal bleeding that often leads to death.

Bird flu viruses mostly infect birds, with many unable to infect other organisms. However, some strains are capable of infecting animals, including pigs and humans.

Four strains have been identified as those of concern, which are H5N1, H7N9, H5N6 and H5N8. Their names refer to two proteins, haemagglutinin and neuraminidase, on the surface of the virus which vary depending on the strain. 

Colouriseed transmission electron micrograph of Avian influenza A H5N1 viruses

Bird flu is caused by a variety of strains of the avian influenza virus. Image © Cynthia Goldsmith/CDC, licensed under Public Domain via Wikimedia Commons

Should I be worried about bird flu?

Most strains of bird flu are poor at infecting humans, with limited numbers of reported cases. This is because the receptors that the virus binds to are not common in humans, especially in the upper airways.

One person has been reported as having contracted bird flu, with UKHSA officials saying that the individual acquired the infection from 'very close, regular contact with a large number of infected birds, which they kept in and around their home over a prolonged period of time.'

They added that the risk of bird flu to the wider public is 'very low', while the Food Standards Agency states that 'properly cooked poultry and poultry products, including eggs, are safe to eat.'

However, there are worries that bird flu viruses could mutate to become better at infecting humans and cause a pandemic. As a result, bird flu is monitored across the world, with countries reporting cases to the World Health Organisation.

Dr Raju Misra, who is head of the Museum's Molecular Biology Laboratories and formerly worked at Public Health England (now UKHSA), says, 'The first stage of a response to any disease is monitoring, just to see if the disease is present, and if so, which variant it is and if it is one of concern. 

'Once detected, a surveillance programme begins to understand how widespread a disease is, and whether there are any hot spots to be concerned about. UKHSA and the Animal and Plant Health Agency (APHA) work together to monitor for any signs that an outbreak could be developing.

'It's a similar strategy that was used for Covid, but bird flu uses many samples taken directly from birds and their faeces, rather than airborne samples. Certain targeted genes are then looked for, and if they are found then the samples are sequenced and compared to a reference database to identify which variant it is. 

'While many are commonly found in the background, there are some which are more concerning and which then need further investigation or action.' 

A sign warning of an avian influenza control measure surveillance zone

Areas where bird flu is suspected or confirmed are subject to exclusion zones. Image © Keith Evans, licensed under CC BY-SA 2.0 via Geograph

What's happening with the current bird flu outbreak?

Bird flu is a seasonal occurrence in the UK, as some wild migratory birds bring the virus with them during winter. The disease can then spread to populations in farms and wildlife sanctuaries when wild birds mix with captive ones.

This season, the first outbreak in a captive population was near Wychavon in Worcestershire, England on 27 October. Since then, at least 65 outbreaks have been recorded in the UK, with outbreaks also taking place across Europe and Russia. 

APHA has described the outbreak as the 'biggest-ever in Great Britain', which has arrived earlier than expected. While the reasons for this are not yet known, there have been some suggestions that climate change is altering the migratory pattern of birds.

Speaking to the BBC's Today Programme, as quoted by the Guardian, Christine Middlemiss said, 'It's certainly one of the thoughts that our experts are having. The birds migrate to the north of Russia over the summer and mix with other birds on other global flight pathways and exchange the viruses. So it's quite plausible that with climate change and change in pathways that different mixing is going on.'

Since 3 November 2021, an avian influenza prevention zone has been declared across Britain to try and limit the spread of the virus. The measures have since been strengthened, with bird keepers required to house all their animals away from wild birds, regularly disinfect enclosures and equipment, and minimise contact between themselves and their animals.

The RSPB also recommends that that anyone with a bird feeder should regularly clean it externally with a mild disinfectant, remove any old food, and space feeders apart as much as possible. 

Two dead birds lie on the ground of a barn

Dead or ill birds should not be touched under any circumstances to avoid the risk of contracting bird flu. Image © kornnphoto/Shutterstock

What should I do if I find a bird which might have bird flu?

Symptoms of infected birds include swollen heads, a lack of coordination and gasping for air. 

Anyone who finds a wild bird that appears to be sick or dead should under no circumstances touch it. Instead, they should call the Department for the Environment, Food and Rural Affairs (Defra) on 03459 33 55 77 to report the bird.

If a captive bird is suspected to have bird flu it must be reported to Defra, as failure to do so is an offence.

Any captive birds which die must be disposed of safely, with advice on how to do so available here. 

For more information, please visit the government's website here.