1. Innogenetics NV, B-9052 Zwijnaarde, Belgium1;
2. Department of Animal Pathology, University of Zaragoza, 50013 Zaragoza,2
3. Instituto Vasco de Investigación y Desarrollo Agrario, 48160 Derio,3 and
4. Department of Veterinary Pathology, University of Edinburgh, EH29 9RG Edinburgh, United Kingdom4; and
5. Department of Animal Pathology, University of Pisa, 56124 Pisa, Italy5
6. Servicio de Investigación Agroalimentaria, SIA-DGA, 50008 Zaragoza,6 Spain;