For Edward Chou, a first-year biochemistry student at the University of Guelph, the symptoms began shortly after lunch on Monday. 

"I just felt something in my stomach and I just started throwing up and I had to go to the toilet multiple times," he said. "It was really bad."

The University of Guelph is responding to an outbreak of a self-reported stomach illness that has affected more than 150 people. The outbreak is part of a rising trend in st…