Contact with the Minnesota DOH identified a cluster of S. sonnei infections with a matching pulsed-field gel electrophoresis (PFGE) pattern. At least one case was in a person who departed Honolulu on Airline A on August 22. Preliminary investigation indicated that airlines A and B shared a common caterer in Honolulu , Catering Company X.
Evaluation of PFGE patterns posted on PulseNet and reports from state health departments have identified 32 confirmed S. sonnei infections among persons with air travel departing Honolulu during August 22-24. An additional 71 persons associated with affected flights have reported a clinically compatible illness, many of whom were identified through an ongoing cohort study of one of the flights. At this time, approximately 87% of the passengers on this flight have been interviewed, and preliminary findings indicate a diarrheal attack rate greater than 55%.
Eleven affected domestic and international flights have been identified on airlines A, B, and C, all leaving Honolulu during August 22-24, and all supplied by Catering Company X. No cases of S. sonnei infection have been reported in persons who departed Honolulu by airline after August 24, and there has been no associated local transmission. The investigation to identify the original source of the S. sonnei is in progress. Industry controls designed to address potential factors that could contribute to a recurrence are being reviewed and reinforced.