1. Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, GA, USA;
2. Office of Noncommunicable Diseases, Injury, and Environmental Health, National Center for Environmental Health, Division of Environmental Hazards and Health Effects, Health Studies Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA;
3. Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA;
4. Office of Public Health Preparedness and Response, Office of Science and Public Health Practice, Office of Applied Research, Centers for Disease Control and Prevention, Atlanta, GA, USA