A Fine, MD, M Layton, MD, J Miller, MD, D Cimini, MPH, MC Vargas, DVM, A Inglesby, MD, the New York City Outbreak Investigation Team, N Cohen, MD; I Weisfuse, MD; A Ramon, MD, I Poshni, PhD, H Stirling, MPH, New York City Dept of Health; T McNamara, DVM, Wildlife Conservation Society, New York City; A Huang, MD, A Rosenberg, MD, P Yang-Lewis, MPH, HN Adel, MD, Westchester County Health Dept, New Rochelle; M Sherman, G Terillion, B Smith, R Porter, A Greenberg, MD, KA Gaffney, MD, Nassau County Dept of Health and Public Works; A Novello, MD, D White, PhD, D Morse, MD, K Spitalny, MD, R Gallo, S Wong, MD, L Grady, MD, M Eidson, DVM, B Wallace, MD, P Smith, MD, State Epidemiologist, New York State Dept of Health. M Cartter, MD, R Nelson, DVM, J Hadler, MD, State Epidemiologist, Connecticut Dept of Public Health; T Andreadis, PhD, Connecticut Agricultural Experiment Station. J Blumenstock, J Degraaf, F Sorhage, DVM, C Campbell, DVM, J Brook, MD, M Gerwell, MD, D Adams, K Bruder, R Kent, R Eisner, DVM, N Halpern, DVM, New Jersey Dept of Agriculture; D Roscoe, DVM, New Jersey Dept of Environmental Protection; E Bresnitz, MD, State Epidemiologist, New Jersey Dept of Health and Senior Svcs. W Crans, PhD, Rutgers Univ, New Brunswick, New Jersey. J Mackenzie, PhD, R Hall, PhD, J Sherret, MSc, Univ of Queensland, Australia. H Artsob, PhD, Laboratory Centre for Disease Control, Health Canada. J Smith, PhD, M Parker, PhD, K Steele, DVM, United States Army Medical Research Institute for Infectious Diseases; National Veterinary Svcs Laboratories, Animal and Plant Health Inspection Svc, US Dept of Agriculture, Ames, Iowa. Infectious Disease Pathology Activity, Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases; Arbovirus Diseases Br, Div of Vector-Borne Infectious Diseases, National Center for Infections Diseases; and EIS officers, CDC.