Day care-related outbreaks of rhamnose-negative Shigella sonnei–six states, June 2001-March 2003

During June 2001–March 2003, outbreaks of Shigella sonnei infections were reported in Delaware, Maryland, New Jersey, North Carolina, South Carolina, and Virginia. Five- to fortyfold increases in statewide shigellosis rates were observed during this period. These increases were attributed primarily to outbreaks in multiple day care settings that became prolonged and community wide. S. sonnei isolates from these states, as well as from New York City and Philadelphia, were similar genetically by pulsed-field gel electrophoresis (PFGE). Many of these isolates lacked the capacity to ferment rhamnose, which is unusual for S. sonnei. This report summarizes these outbreaks and describes the laboratory characteristics that link them. The findings underscore the importance of rapid and coordinated public health responses to isolated outbreaks of shigellosis.