1. Department of Molecular Genetics and Microbiology, Emerging Pathogens Institute, College of Medicine, University of Florida, Gainesville, FL, USA.
2. Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA.
3. Department of Periodontology, College of Dentistry, University of Florida, Gainesville, FL, USA.
4. Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA.
5. Department of Medicine, Division of Infectious Diseases, University of Florida, Gainesville, FL, USA.
6. Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.