SEATTLE — Health officials expect the number of people sickened by an E. coli outbreak linked to Chipotle restaurants in Washington state and Oregon to grow while they investigate the cause of the infection.

As of Friday, three people in the Portland area and 19 people in western Washington had become sick from E. coli. Seventeen of them had eaten at a Chipotle restaurant during the past few weeks.

Eight people have been hospitalized but no deaths have been reported.

After people start hearing about the outbreak, more people will probably go to the doctor and join the list of potential cases, said Marisa D’Angeli, medical epidemiologist with the Washington State Department of Health.

D’Angeli encouraged anyone who has been sick with intestinal symptoms and has eaten at Chipotle since mid-October, to go see their doctor and get tested.

Symptoms of E. coli infection include diarrhea, abdominal cramps, nausea and vomiting.