1. California Institute for Medical Research,1 and
2. Department of Medicine, Division of Infectious Diseases,2 Santa Clara Valley Medical Center, San Jose, California 95128;
3. Department of Medicine, Division of Infectious Diseases and Geographic Medicine,3 and
4. Department of Pathology,4 Stanford University, Stanford, California 94305;
5. Palo Alto Veterans Affairs Health Care System,5 Palo Alto, California 94304; and
6. Kaweah Delta District Hospital, Visalia, CA 932916