TDH staff were skeptical of the student's report but felt that a minimal amount of exploration was necessary. They began by making a few telephone calls to establish the facts and determine if other persons were similarly affected. The pizzeria, where the student and his roommate had eaten, was

closed until 11:00 A.M. There was no answer at the University Student Health Center, so a message was left on its answering machine.

A call to the emergency room at a local hospital (Hospital A) revealed that 23 university students had been seen for acute gastroenteritis in the last 24 hours. In contrast, only three patients had been seen at the emergency room for similar symptoms from March 5-9, none of whom were associated with the university.

At 10:30 A.M., the physician from the University Student Health Center returned the call from TDH and reported that 20 students with vomiting and diarrhea had been seen the previous day. He believed only 1-2 students typically would have been seen for these symptoms in a week. The Health Center had not collected stool specimens from any of the ill students.

Do you think these cases of gastroenteritis represent an outbreak at the university? Why or why not?