1. Centro de Biología Molecular “Severo Ochoa” (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), 28049 Cantoblanco, Madrid, Spain
2. Ciemat, Avda. Complutense 22, 28040 Madrid, Spain
3. Department of Veterinary Population Medicine, University of Minnesota College of Veterinary Medicine, St. Paul, Minnesota 55108
4. Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut