This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

DENVER — Illnesses from chicken salad bought at Costco in Colorado and six other states are under investigation.

The Centers for Disease Control and Prevention said Tuesday 19 people were sickened in the outbreak in seven states. Four of those people were in Colorado.

Consumers with “Chicken Salad made with Rotisserie Chicken” item number 37719 purchased from Costco in Colorado should discard it.

Four cases of E. coli are confirmed in Colorado. Two happened in Jefferson County and one each happened in Arapahoe and Routt counties. One person required hospital treatment. All four patients have recovered. Five people total have been hospitalized in all seven states.

They bought the chicken salad on Oct. 25 and Oct. 26, and got sick between Oct. 28 and Nov. 3. Cases of E. coli traced to the Costco chicken salad also occurred in Utah, Montana, Washington, California, Missouri and Virginia

Health experts are working with Costco to find out the sources of contamination.

“We are working with Costco,” said Alicia Cronquist, an epidemiologist at the Colorado Department of Public Health and Environment. “FDA reported to us the product has been removed from the shelves and no longer is for sale in Colorado.”

One case in Washington was not as serious. The person from King County was not hospitalized, the Washington State Department of Health said.

“We take E. coli very seriously in Washington,” State Epidemiologist Dr. Scott Lindquist said in a statement. “We are working with the CDC and state partners to determine the source.”

The state health departments along with the Centers for Disease Control and Prevention, the U.S. Food and Drug Administration and the U.S. Department of Agriculture are working with Costco to figure out what the exact source of the contamination is.

The FDA confirmed to the Colorado Department of Public Health and Environment that the chicken salad has been pulled from store shelves in that state.

If you’ve eaten some and start to feel sick, make sure you call your doctor. People typically get sick two to eight days after eating food infected with E. coli. Symptoms can include abdominal cramps and diarrhea, which can sometimes be bloody.

Most people who get sick from E. coli recover within a week; however, people with chronic conditions can experience much more severe symptoms that can include kidney failure. The elderly and children are particularly vulnerable.