It may be possible to assess next week whether controls on the movement of livestock have prevented fresh outbreaks of foot-and-mouth, Britain's chief veterinary officer, Mr Jim Scudamore, said yesterday.
The two-week incubation period for the disease ends in another week, and government vets would then be in a position to assess whether the ban on the movement of all livestock imposed on February 23rd had contained the disease, he said.
"Most of the animals, if they are going to develop the disease, should be showing signs last week and this week and possibly some overflow into next week," he said.
"So the first evidence is that, because we stopped all movements, we stopped the spread of the disease."
Six new cases were confirmed yesterday, bringing the total to 80.
The cases were found at farms in Durham and Devon and at four farms in Cumbria.
A suspected outbreak on Dartmoor, at Widecombe in the Moor, near the first confirmed case in the area on Duchy of Cornwall land, was being investigated, Mr Scudamore said.
He dismissed speculation that the first outbreak was spread by the wind, saying this was a factor only when pigs were involved.
The Dartmoor outbreak affected sheep on the Dunna Bridge farm. The most likely cause, he said, was that the disease had been spread by the movement of animals roaming freely on the moor close to the farm.
However, a cull of wildlife could make matters worse, Mr Scudamore said. "At the moment, any move to deal with deer on Dartmoor or . . . clear sheep or other animals off the moor would be counterproductive and could actually cause more problems than it would resolve," he told BBC Radio 4's Today programme.
Mr Nick Brown, Britain's Agriculture Minister, insisted animals were not being killed "gratuitously" and ruled out culling ponies on Dartmoor. It would be a "slightly separate" issue, he said, when considering what to do with the wild deer on the moor, should the chief vet recommend culling wildlife.
Meanwhile, the National Farmers' Union appealed to the Jockey Club not to resume horse racing today, asking for the ban to remain for another week to prevent spread of the disease. Some trainers said the decision to resume racing was correct because it was based on a scientific assessment of the risk.