Britain's health and safety agency said Tuesday there was a strong probability that a foot-and-mouth outbreak in southern England originated at a vaccine lab and was spread by human movement.
The outbreak was discovered on a farm just 4 miles from the Pirbright vaccine laboratory, which is shared by the government's Institute for Animal Health and a private pharmaceutical company, Merial Animal Health, the British arm of Merial Ltd. of Duluth, Ga.
There is a "real possibility" the disease was spread by human movement, and the possibility it was transmitted by air or floodwaters was "negligible," the government's Health and Safety Executive said in the report.
The highly contagious disease can be carried by wind and on the vehicles and clothes of people who come into contact with infected animals.
A group of cows at a second farm was confirmed to have the disease Tuesday. Cranes piled cattle carcasses onto trucks, and authorities expanded the protection zone around the second farm.
Both farms, about 30 miles southwest of London, were within the initial 2-mile protection zone set up Friday, said Environment Secretary Hilary Benn.
News of a second confirmed outbreak fed fears of a repeat of 2001, when 7-million animals were killed and incinerated on pyres, devastating agriculture and rural tourism in Britain.
Foot-and-mouth disease affects cloven-hoofed animals, including cows, sheep, pigs and goats, but does not typically affect humans.
Britain has banned the export of livestock, meat and milk.