The federal public health agency wants Canadians to think about staying away from romaine lettuce.

The Public Health Agency of Canada says 40 E. coli illnesses are under investigation as possibly being linked to romaine, including eight in Ontario. The tally includes 16 cases which have resulted in hospitalization and one which has been fatal.

According to the agency, people who have experienced illness range in age from four to 85.

Reports of illnesses began in November, and continue to come in.

“Contaminated romaine lettuce may still be on the market (including in restaurants, grocery stores and any establishments that serve food),” the agency said Thursday in a notice posted to its website.

“Individuals in Ontario, Quebec, New Brunswick, Nova Scotia, and Newfoundland and Labrador are advised to consider consuming other types of lettuce, instead of romaine lettuce, until more is known about the outbreak and the cause of contamination.”

While romaine is believed to be the cause of the outbreak, the specific source has not been identified. People who have reported illnesses have said that they ate romaine at home, at restaurants and in prepared salads purchased from grocery stores.

Officials say there is no reason to believe the outbreak has spread west of Ontario.

E. coli bacteria can cause symptoms like nausea, vomiting, headaches, stomach cramps and diarrhea.