Foot and mouth disease. Smoke rising from pyres of burning cows slaughtered to prevent the spread of foot and mouth disease. This disease is caused by several viruses in the picornavirus group. It infects domestic and wild cloven-hooved animals, causing a fever followed by the development of blisters in the mouth and on the feet. It is highly contagious, spreading by contact with infected animals and animal products, in the air and on materials exposed to infection. Diseased areas are quarantined to avoid further spread. Photographed near Kirkoswald and Lazonby in Cumbria, England, in early 2001.