1. Department of Internal Medicine, University of South Dakota Sanford School of Medicine, Sioux Falls, South Dakota, USA
2. Department of Internal Medicine, Oregon Health & Science University, Portland, Oregon, USA
3. Infectious Disease Service, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
4. Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
5. Infectious Disease Service, Brooke Army Medical Center, San Antonio, Texas, USA