1. U.S. Food and Drug Administration, Center for Veterinary Medicine, U.S. Department of Health and Human Services, Laurel, Maryland, USA
2. National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, Maryland, USA
3. U.S. Food and Drug Administration, Center for Veterinary Medicine, U.S. Department of Health and Human Services, Rockville, Maryland, USA
4. Centers for Disease Control and Prevention, Division of Foodborne, Waterborne, and Environmental Diseases, U.S. Department of Health and Human Services, Atlanta, Georgia, USA