1. Center for HUS Control, Prevention and Management,
2. Epidemiology Unit,
3. Laboratory of Medical Genetics,
4. Pediatric Cardiology Unit, and
5. Unit of Microbiology, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy;
6. Division of Pediatrics, Department of Health Science, University of Piemonte Orientale, Novara, Italy;
7. Istituto Superiore di Sanità, Roma, Italy; and
8. Univerità di Bologna, Bologna, Italy