[1
]
1 Department of Epidemiology, Colorado School of Public Health, University of Colorado
Denver , Aurora, Colorado.
[2
]
2 Enteric Diseases Epidemiology Branch, Division of Foodborne, Waterborne, and Environmental
Diseases, Centers for Disease Control and Prevention , Atlanta, Georgia .
[3
]
3 Biostatistics and Information Management Office, Division of Foodborne, Waterborne,
and Environmental Diseases, Centers for Disease Control and Prevention , Atlanta,
Georgia .