1. Epidemiology and Surveillance Unit, Centre for Infectious Disease Control, RIVM (National Institute of Public Health and the Environment), P.O. Box 1, 3720BA Bilthoven, The Netherlands, Center for Global Safe Water at Emory, Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States, American Water, Voorhees, New Jersey, United States, and Campbell’s North American Food Service, Everett, Washington, United States