J. THOMAS GRAYSTON, Department of Epidemiology, University of Washington

GEORGE A. JACOBY, JR., Infectious Disease Unit, Massachusetts General Hospital

GERALD L. MANDELL, (Chair),* Division of Infectious Diseases, Department of Internal Medicine, University of Virginia

WILLIAM A. PETRI, JR. (Rapporteur), Medicine and Microbiology, Divisions of Infectious Diseases and Geographic Medicine, University of Virginia Health Sciences Center

P. FREDERICK SPARLING,* Department of Medicine, University of North Carolina School of Medicine

ANDREW SPIELMAN,* Department of Tropical Public Health, Harvard School of Public Health

DAVID H. WALKER, Department of Pathology, University of Texas Medical Branch

RICHARD P. WENZEL, Department of Clinical Epidemiology, University of Iowa Hospital

Task Force 2 met in Washington, D.C., on May 16-17, 1991, with the following participants:

BRUCE F. ELDRIDGE, University of California Mosquito Research Program, Department of Entomology, University of California at Davis

PATRICIA N. FULTZ,* Department of Microbiology, University of Alabama at Birmingham

DUANE J. GUBLER, Vector-Borne Infectious Diseases Division, National Center for Infectious Diseases, Centers for Disease Control

JAMES L. HARDY, School of Public Health, University of California at Berkeley

FREDERICK G. HAYDEN, Department of Internal Medicine, University of Virginia Hospital

JOHN J. HOLLAND,* Department of Biology and Institute for Molecular Biology, University of California at San Diego

RICHARD T. JOHNSON, Department of Neurology, Microbiology, and Neuroscience, Johns Hopkins University School of Medicine

EDWIN D. KILBOURNE,* Department of Microbiology, Mount Sinai School of Medicine

STEPHEN S. MORSE (Chair),* Rockefeller University