Vets have ordered 5,000 turkeys to be slaughtered at a free-range farm in Norfolk after bird flu returned to Britain for the first time since it was recorded at a plant run by the Bernard Matthews firm in February.
The discovery of the disease at the farm in Diss, on the border with Suffolk, comes as another blow for farmers affected already this year by outbreaks of bluetongue and foot-and-mouth.
The Department for the Environment, Food and Rural Affairs said early tests showed the turkeys had the H5 strain of bird flu, but it is not yet known if it is a highly pathogenic form. A 3km (1.9mile) protection zone and 10km surveillance zone has been set up around the farm, which has not been named. It keeps ducks and geese as well as turkeys.
The deputy chief veterinary officer, Fred Landeg, said the cause of the infection was unknown, and urged all poultry farmers to remain vigilant. "Everybody needs to be concerned. This is avian influenza," he said. " We are asking every poultry keeper to be vigilant, to house their birds where they are required to do so in any restricted area and carry out good bio-security measures and report any signs of disease."
Dr Landeg added: "We will be looking at the movements on to the premises and off the premises of birds; and movements of people, vehicles and things, to see whether there is another origin somewhere in the country or whether the disease could have spread."
Defra said that inside the zones bird movements have been restricted and all farm birds must be housed and isolated from wild birds.
Peter Kendall, president of the National Farmers' Union, expressed support for the Government's measures but stressed that "there is no reason for public concern".
"We fully support the measures Defra have put in place in the protection and surveillance zones and we will be working with them to make sure producers within the zones understand the implications of the restrictions," he said. "But it is important to remember that avian influenza is a disease of birds. There is no reason for public concern and the Food Standards Agency says there are no risks from eating poultry meat and eggs provided they are cooked properly as, of course, all food should be."
The EU Commission has been informed and notification is being sent to all poultry keepers on the British poultry register.
The shadow Environment Secretary, Peter Ainsworth, described the bird flu outbreak – the first incidence of the H5 strain in the UK since 159,000 turkeys were slaughtered at the Bernard Matthews farm – in extreme terms. He said: "This is yet another nightmare for the farming community and we can only hope that this is an isolated case. Farmers have endured so much this year, the last thing they need is an outbreak of bird flu in the run-up to Christmas."
Chris Huhne, the Liberal Democrat's spokesman on the environment, said: "Another outbreak of bird flu after the Bernard Matthews incident makes it a hat-trick of horror stories for British farming this year: foot and mouth, bluetongue and now bird flu again. Ministers must pull out all the stops to contain this outbreak and identify its source."
The infected premises is thought to be a free-range farm with outdoor turkeys, geese and ducks. Bernard Matthews said that its farms were not involved.Reuse content