1. Department of Occupational and Environmental Health, University of Iowa College of Public Health, Iowa City, Iowa
2. Center for Emerging Infectious Diseases, University of Iowa College of Public Health, Iowa City, Iowa
3. Department of Epidemiology, University of Iowa College of Public Health, Iowa City, Iowa
4. Center for Animal Health and Food Safety, University of Minnesota, St. Paul, Minnesota
5. Department of Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
6. Program of Hospital Epidemiology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
7. Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, Iowa