Margo E. Chase-Topping , Tracy Rosser, Lesley J. Allison, Emily Courcier, Judith Evans, Iain J. McKendrick, Michael C. Pearce, Ian Handel, Alfredo Caprioli, Helge Karch, Mary F. Hanson, Kevin G.J. Pollock, Mary E. Locking, Mark E.J. Woolhouse, Louise Matthews, J. Chris Low, and David L. Gally

Author affiliations: University of Edinburgh, Edinburgh, UK (M.E. Chase-Topping, E. Courcier, M.C. Pearce, M.E.J. Woolhouse); The Roslin Institute and Royal (Dick) School of Veterinary Studies, Edinburgh (T. Rosser, I. Handel, D.L. Gally); Scottish E. coli O157/VTEC Reference Laboratory, Edinburgh (L.J. Allison, M.F. Hanson); Scottish Agricultural College, Edinburgh (J. Evans, M.C. Pearce, J.C. Low); Biomathematics and Statistics Scotland, Edinburgh (I.J. McKendrick); Istituto Superiore di Sanità, Rome, Italy (A. Caprioli); University of Münster, Münster, Germany (H. Karch); Health Protection Scotland, Glasgow, UK (K.G.J. Pollock, M.E. Locking); University of Glasgow Veterinary School, Glasgow (L. Matthews)