1. Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado
2. Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
3. Bureau of Laboratories, Pennsylvania Department of Health, Lionville, Pennsylvania
4. Massachusetts Department of Public Health State Laboratory Institute, Jamaica Plain, Massachusetts
5. Caritas St. Elizabeth's Medical Center, Boston, Massachusetts
6. Division of Bioterrorism Preparedness and Response, Centers for Disease Control and Prevention, Atlanta, Georgia