1. Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University , New Orleans, Louisiana 70112 , USA
2. Oak Ridge Institute for Science and Education, CDC Fellowship Program, Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention , Atlanta, Georgia 30333 , USA
3. Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention , Atlanta, Georgia 30333 , USA