1. Wadsworth Center, New York State Department of Health, Albany, New York, USA
2. Center for Biological Sciences, Providence, Rhode Island, USA
3. Rhode Island State Health Laboratory, Providence, Rhode Island, USA
4. Rhode Island Department of Health, Providence, Rhode Island, USA
5. Center for Acute Infectious Disease Epidemiology, Providence, Rhode Island, USA
6. Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA