Abstract
1 Centers for Disease Control and Prevention, National Center for Zoonotic, Vector-borne, and Enteric Diseases, Division of Viral and Rickettsial Diseases, 1600 Clifton Road NE, Atlanta, GA 30333, USA
2 Saint Louis University School of Medicine, Division of Infectious Diseases and Immunology, Edward A. Doisy Research Center, 8th Floor, 1100 S. Grand Blvd, St Louis, MO 63104, USA
3 The EMMES Corporation, 401 N. Washington St, Rockville, MD 20850, USA