Within the last 2 days, 53 students have come to the student health center with similar symptoms, all of which began suddenly. Of the 53 students:
91% are vomiting.
87% have nausea.
72% have diarrhea.
67% have stomach cramps.
61% have a fever.
53% have a headache.
The medical staff tells you that they have diagnosed the students with acute gastroenteritis. However, the routine tests at the student health center did not identify the cause.