1. Department of Epidemiology, University of Florida, Gainesville, Florida, USA.
2. Department of Pathology, University of Florida, Gainesville, Florida, USA.
3. Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA.
4. Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA.
5. Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA.