BBCRestrictions on the movement of sheep and cattle have been introduced across two counties after more animals tested positive for the bluetongue virus.
The Department for Environment, Food & Rural Affairs (Defra) said a restricted zone was now in place around Norfolk and Suffolk.
UK Chief Veterinary Officer Christine Middlemiss said: “This means all keepers in these regions must urgently act now to both prevent the disease spreading to their herds and any further.”
Defra said keepers of cattle, sheep, camelids, including llamas and alpacas, and other ruminants must remain vigilant and follow the restrictions applying to animal movements.
Stuart Woodward/BBCDr Middlemiss said: “Farmers are urged not to move animals within the zone unless it is absolutely necessary.
“We have not taken this action lightly and we are clear that farmers and their vets must remain vigilant and report any suspicions to the Animal and Plant Health Agency immediately.”
Bluetongue is spread by the bites of midges and can cause infertility and breathing problems in sheep, cattle and goats, but does not affect people or food safety.
The virus was first detected at a farm close to Haddiscoe, near Beccles, on Monday, and a 20km (12.4 mile) temporary control zone (TCZ) put into place.
The TCZ was extended on Wednesday after more cases were found, but by Friday animals were testing positive for the virus in both counties.
‘Notifiable disease’
A Defra statement said: “We are committed to working with everyone affected to help them protect their animals and those of neighbouring farmers, and we will keep the size and nature of the zone under constant review as our understanding of the disease picture develops.
“Bluetongue virus is a notifiable disease. Suspicion of bluetongue virus in animals in England must be reported to the Animal and Plant Health Agency.”
Last winter, a similar TCZ was in force around a farm in the Norfolk town of Acle after a number of animals tested positive. Restrictions were lifted in February.
Between November and March there were 126 bluetongue cases across four counties in England.
They included 119 cases in cattle and seven in sheep. Defra said the disease could prove fatal for infected animals “in the most severe cases”.
