Farmers urged to be on alert for highly pathogenic form of bird flu

Anne Gulland
UK authorities have robust measures to tackle bird flu outbreaks in farms - Laurent Gillieron/Keystone
UK authorities have robust measures to tackle bird flu outbreaks in farms - Laurent Gillieron/Keystone

Farmers and bird keepers are being urged to be on the alert for a highly pathogenic strain of avian flu that is circulating in Europe and has led to the culling of more than 13,000 chickens at a farm in Cheshire earlier this month.

The H5N8 avian influenza virus currently poses no risk to humans but the number of outbreaks has been increasing in recent years.

This highly pathogenic strain – meaning that it leads to more severe disease in birds rather than it being more easily transmissible – has been identified on several farms in Europe this year and led to the culling of more than 200,000 chickens on a farm in the Netherlands last week.

The Department for the Environment, Food and Rural Affairs (Defra) has also confirmed that three wild geese found dead in Gloucestershire have tested positive for the same highly pathogenic strain of the virus. Experts are currently investigating whether these deaths are linked to the Cheshire outbreak.

Defra has raised the risk level for the disease being introduced to poultry premises in the UK from ‘low’ to ‘medium’.

The UK’s chief veterinary officer Christine Middlemiss said the risk to public health is very low and added: “The Food Standards Agency advises that bird flu poses a very low food safety risk for UK consumers. Bird keepers should remain alert for any signs of disease, report suspected disease immediately and ensure they are maintaining good biosecurity on their premises,” she said. 

The last outbreak of a highly pathogenic H5N8 hit 29 European countries in 2016-17, including the UK, and led to the culling of millions of poultry across the continent. In Germany alone 900,000 birds were killed. 

The UK was previously declared free of avian flu in September 2017 and has remained free of highly pathogenic avian influenza since.

Northern and eastern Europe is most at risk of an outbreak of H5N8 although the disease may spread to southern and western parts of the continent, the European Centre for Disease Control has said, urging European countries to be on the alert for the disease. 

The same strain has also been reported in South Korea although experts believe the outbreaks are unlikely to be related.  The virus was discovered in samples collected from wild birds last week , the agriculture ministry said in a statement.

The ministry said it has ramped up prevention measures to contain a wider spread of bird flu and issued a highly pathogenic avian influenza warning.

Dr Holly Shelton, an expert in influenza viruses at the Pirbright Institute, said there had been no significant outbreaks of bird flu in the UK in recent years. But the recent outbreaks in Europe meant the UK was likely to follow the same pattern. 

“The way bird flu is transmitted is through migratory birds. It’s the prime season for birds summering in Russia and Asia to be making trips to Africa for the winter. A fair number of these paths cross Europe and they stop at various places because it’s a long journey,” she said. 

She said the authorities have robust measures to tackle outbreaks.

“As soon as an outbreak is detected they have a stamping out control method where they isolate the farm, euthanise the birds and put restrictions on animal movements in the local area,” she said.

Dr Shelton added that it was important to monitor outbreaks for any potential spread to humans but there have been no recorded cases of this particular strain in humans anywhere in the world. 

“All influenza viruses have the potential to evolve and generate changes that might cause it to jump into another host species,” she said, adding that these viruses have to undergo multiple changes to make them spread in human populations.

“There are no characteristics in H5N8 that give us cause for concern that it might jump from person to person. But we still have to treat the viruses with care as the likelihood of them adapting will increase if they make small jumps into individuals,” she said. 

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