1. 1Enteric Diseases Epidemiology Branch, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road N.E., M/S D63, Atlanta, Georgia 30333
2. 2Foodborne Disease Investigations Branch, U.S. Department of Agriculture, Food Safety and Inspection Service, 1400 Independence Avenue S.W., Washington, DC 20250
3. 3Minnesota Department of Health, 85 7th Place E., No. 220, St. Paul, Minnesota 55101
4. 4California Emerging Infections Program, 360 22nd Street, Suite 750, Oakland, California 94612
5. 5Nashville–Davidson County Metro Public Health Department, 1 Public Square, No. 106, Nashville, Tennessee 37201
6. 6Microbiological Issues Branch, U.S. Department of Agriculture, Food Safety and Inspection Service, Aerospace Center, Room 344, 1400 Independence Avenue S.W., Washington, DC 20250
7. 7Environmental Health Services Branch, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta, Georgia 30341, USA