LONDON, Sep 15 (Reuters) Foot and mouth disease that infected livestock at four sites in southern England was all of the same strain, Britain said today.
Hundreds of cattle and pigs have been slaughtered in the latest outbreak at two farms in Surrey, southeast England. Two other nearby sites were hit by the virus in August.
''All four premises that have been infected are infected by the same strain of virus,'' Chief Veterinary Officer Debby Reynolds told a news conference in London.
Officials imposed a surveillance zone of 6 miles (10 km) around the latest farms to be hit.
The European Union banned British exports of meat, live animals and dairy products until October 15 after the latest outbreak this week.
Foot and mouth is a highly infectious disease which can spread on the wind. It can cause animals to foam at the mouth and collapse, and sometimes kills.
Britain suffered a crippling outbreak of foot and mouth in 2001, when more than 6 million animals had to be culled.
After the latest outbreaks, Queen Elizabeth was banned from riding her horse or letting her dogs off the leash on her Windsor estate, which falls under the control regulations.
An investigation into the August outbreak highlighted biosecurity breaches at a nearby government-funded laboratory, the Institute of Animal Health at Pirbright.
REUTERS GT BST1632