1. Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention , Atlanta, GA 30333 , USA
2. Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health , Bethesda, MD 20892 , USA
3. Westat , Rockville, MD 20850 , USA
4. National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, MD 20892 , USA