Foot and mouth disease protein. Computer artwork of the structure of a protein from the foot and mouth disease virus. Four domains (sections, red, green blue and yellow) of the protein are shown. Each has a folded structure composed of amino acid sheets (flat) and helices (spirals). The virus causes foot and mouth disease in cloven-hooved animals. Symptoms include a fever, and blisters on the feet and in the mouth. The virus is highly contagious, spreading by contact with infected animals and animal products, in the air and on materials exposed to infection. The rapid spread of the disease can cause epidemics, requiring quarantining and slaughter of infected animals.