1. Meningitis and Special Pathogens Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases,1 and
2. Laboratory Services Branch, Ontario Ministry of Health, Toronto, Canada2
3. Epidemiology and Surveillance Division, National Immunization Program,3 Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services, Atlanta, Georgia, and