Germany sealed off five farms as a precautionary measure following an outbreak of the livestock disease foot-and-mouth in Britain, DPA quoted officials as saying today. Four of the farms, in Hesse and Rhineland-Palatinate states, had recently purchased sheep from a farm 150 kilometres from the site of the outbreak in southern England. The fifth farm was in the eastern state of Mecklenburg-West Pomerania, where a horse imported from England was under quarantine. Officials said livestock at the farms would be examined and placed under observation and that no transport of animals to or from the farms would be permitted until after the ban was lifted. Mecklenburg-West Pomerania Agriculture Minister Till Backhaus said controls at international seaports and airports had been stepped up and appealed to travellers not to bring back any food products from Britain. Officials in Britain have identified a laboratory complex as the possible source of the foot-and-mouth outbreak near Guilford in Surrey. The strain of the disease is identical to that used for vaccines developed at a research site where the Institute for Animal Health is located at Pirbright, 5 kilometres from the farm where the outbreak was confirmed late Friday.