1. Department of Microbiology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
2. Department of Biology, Frostburg State University, Frostburg, Maryland, USA
3. Department of Medicine, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
4. National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, USA
5. The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA
6. Department of Pathology, Johns Hopkins Hospital, Baltimore, Maryland, USA
7. Laboratory for Biological Ultrastructure, Department of Biology, University of Maryland, Silver Spring, Maryland, USA