1. Scientific Resources Program, National Center for Infectious Diseases, Coordinating Center for Infectious Diseases, Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services, Atlanta, Georgia 30333
2. Atlanta VA Medical Center, Decatur, Georgia 30033
3. Division of Parasitic Diseases, National Center for Infectious Diseases, Coordinating Center for Infectious Diseases, Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services, Atlanta, Georgia 30333
4. Department of Environmental Health Sciences, Division of Environmental Health Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205