Authorities in Britain are investigating a fourth possible case of foot-and-mouth disease, raising fears of a breach in the existing control zone. Two cases have been confirmed at neighbouring farms in Surrey, south-east England. A third suspected outbreak is being looked into within that protection zone. The fourth farm is situated nearby but outside the control zone. A new 3-kilometer perimeter has been set up around it while tests continue. The farm’s owner is confident a virus that has affected 65 of his calves is not foot-and-mouth. Animal health labs in the vicinity are suspected of being the source of last week’s outbreak which has so far seen nearly 600 cattle culled. The laboratories say they have respected all safety procedures. Meanwhile, the government has lifted restrictions on the transport of animals to abattoirs, but a ban on the movement of livestock to other farms and markets continues.