An electronic link to the Web-based cohort study survey was distributed on July 20, 2002, to 1,100 Transplant Games attendees. Among these 1,100, we received survey responses from 369 persons (34%) in 42 states; 80% responded within 48 hours. Of the 369, a total of 82 (22%) reported illness and 41 (53%) were female. The median age of ill respondents was 47 years (range 4-71 years); 48 (59%) were transplant recipients. Dates of symptom onset were June 26-July 7 (Figure) . Predominant symptoms included diarrhea (93%), abdominal pain (79%), and fever (51%). Three respondents (4%) had been hospitalized. No deaths were reported to the organizers of the Transplant Games or CDC. Among ill respondents, 75 (91%) reported eating food items at specific food courts in theme park A.