Foot and mouth containment at a farm. Sign prohibiting access to a farm where foot and mouth was found in an effort to prevent the spread of the disease. Foot and mouth is caused by viruses in the picornavirus group. It infects domestic and wild cloven-hoofed animals, causing fever followed by the formation of blisters in the mouth and on the feet. It is highly contagious, spreading by direct contact with infected animals and animal products, through the air and with the movement of contaminated equipment and people. Infected farm animals are slaughtered and burnt to remove contamination. Photographed at a farm in Egham, Surrey in September 2007.