The contagious, flu-like gastrointestinal norovirus has affected 18 patients and 11 staff at the Credit Valley Hospital in Mississauga, Wendy Johnson, the hospital's director of communications told the Toronto Star.

"It's like a big traffic jam in the emergency room," said Alicia Sarabia, an infectious disease consultant. "The repercussion is that patients in the ER who need a hospital bed can't get one."

She said 91 beds in two nursing units have been closed until the outbreak is eliminated.

Sarabia said the outbreak began more than two weeks ago in three units, but one of them is now clear.

Norovirus can be spread by contact and causes nausea, vomiting, diarrhea, headaches and mild fever, and does not usually cause serious illness in healthy individuals, the report said.