1. Channing Laboratory, Brigham and Women's Hospital; Division of Infectious Disease, Beth Israel Hospital; Department of Medicine, Harvard Medical School, Boston, MA
2. Division of Infectious Disease, Roger Williams Hospital Department of Medicine, Brown University Medical School, Providence, RI
3. Rhode Island Health Services Research, Inc., Providence, RI
4. Division of Epidemiology, Department of Health, State of Rhode Island, Providence, RI
5. Departments of Social Medicine and Clinical Microbiology, Hadassah University Hospital, Hebrew University, Jerusalem, Israel