1. Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention , Atlanta, GA, USA
2. Minnesota Department of Health , St Paul, MN, USA
3. Georgia Department of Public Health , Atlanta, GA, USA
4. Colorado Department of Public Health and Environment , Denver, CO, USA
5. Connecticut Emerging Infections Program, Yale School of Public Health , New Haven, CT, USA
6. University of New Mexico Health Sciences Center , Albuquerque, NM, USA
7. New York State Department of Health , Albany, NY, USA