LONDON, England (CNN) -- International bans were slapped on British farming exports Monday as the country scrambled to contain an outbreak of foot-and-mouth disease, halting work at a vaccine lab suspected to be the source of the infection.
The UK government has sealed off areas around the outbreak in an effort to contain the disease.
The bans came shortly before Britain's Department for Environment, Food and Rural Affairs reported another herd has shown signs of the highly contagious disease and may be infected. More than 50 cattle are involved in the latest suspected case, and culling has begun, the agency said.
The European Union said it would restrict all live animals, fresh meat and milk products from mainland Great Britain after laboratory results Friday confirmed the disease was found in cattle at a farm in Surrey County, England.
The move is likely to put heavy financial strain on the country's beleaguered farming industry, still suffering from a 2001 outbreak of the highly contagious virus that led to the culling of millions of animals, many in giant pyres.
A day after British Prime Minister Gordon Brown vowed the government would do everything in its power to halt the outbreak, the vaccine lab at Pirbright, southwest of London, under investigation over the infection said it had suspended production.
"On Saturday night, we took the voluntary decision to suspend all production here at our Pirbright center," said David Biland, managing director for pharmaceutical company Merial Animal Health.
Biland said internal investigations showed no breach in procedures.
Announcing its ban, EU Commission spokesman Philip Tod declared all of Britain except Northern Ireland as a "high-risk area," but also praised the country's government for taking swift action.
"We welcome the speed with which the British authorities have confirmed the strain of the virus which is being dealt with and will await the results of their investigation into the possible origins of the outbreak," Tod said.
Over the weekend, Britain's DEFRA said the strain of the virus identified in the new farm outbreak was the same as one produced at the Pirbright laboratories a few miles away.
The Pirbright site is home to Merial Animal Health and the government-run Institute for Animal Health, which both use that strain of the foot and mouth virus for research and to develop vaccines.
"Having identified a potential source, we've got to look at the transmission mechanism for the disease," Brown said on Sunday.
Culling of the 38 infected cattle in Surrey was completed Saturday, DEFRA said in a posting on its Web site. Cattle on two additional sites that together make up the enterprise and animals on an adjacent farm were also culled.
One of the additional cattle tested positive for the illness, it said.
Biland defended Merial in the statement he read outside the facility Monday morning.
"As I said last night, this site operates to the very highest international standards and we have complete confidence in the integrity of our operation here," Biland said.
"To date, our investigations continue to show no breach in our procedures; however, it is still too early in this investigation for anyone to determine the cause of the outbreak."
Inspectors will visit the Merial factory and the research laboratory "to be sure the biosecurity is in place and that we are satisfied with the arrangements," Brown said.
He added that it remains unclear just how the animals became infected.
The 2001 foot-and-mouth outbreak in the UK -- blamed for nearly 2,000 cases of the disease -- led to the slaughter of more than 3.5 million sheep, cows and pigs in a bid to contain the disease. The government was accused of reacting too slowly, allowing the disease to spread.
Foot-and-mouth disease affects cattle, swine, sheep, goats, deer and other animals, according to the U.S. Department of Agriculture. Learn more about foot-and-mouth disease »
Environment Secretary Hilary Benn said that the IAH carries out tests on foot-and-mouth at Pirbright, while Merial manufactures animal vaccines for the authorities in the UK and abroad.
"We do know that last month they were manufacturing a batch of vaccine that included this strain," he said.
Asked if he could rule out sabotage or terrorism as a cause for the outbreak, Benn responded: "We simply do not know, and that is why these urgent investigations are taking place at both parts of the site."
Biland said the company has been manufacturing vaccines for 15 years under strict adherence to quality control standards and never had such a problem, but welcomed the investigation and would comply with it. E-mail to a friend
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