The CDC stresses, however, that most of the newly reported cases involve people who fell ill two to three weeks ago, when contaminated lettuce from the Yuma, Ariz., area was still available to consumers.
According to the latest CDC update, there have been a total of 197 illnesses, 89 hospitalizations and five deaths in 35 states.
The Food and Drug Administration, which is investigating the outbreak with the CDC, has said it believes it can be traced to romaine lettuce sourced from the Yuma growing region in Arizona. Two people from Minnesota, one person from Arkansas and one person from NY have died, according to the update.
The outbreak is the largest in the United States since 2006, when spinach tainted with a similar strain of E. coli sickened more than 200 people.
However, the lettuce from that region is past its shelf life and is likely no longer being sold in stores or served in restaurants, the FDA said.
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Officials also noted that some of the individuals who became ill never actually consumed the contaminated lettuce but were in close contact with someone else who had done so. Illnesses started on dates ranging from March 13, 2018 to May 12, 2018.
Numerous new cases were people who became ill two to three weeks ago, when contaminated lettuce was still being sold.
Meanwhile, government authorities are still trying to figure out how and why the outbreak happened.
Symptoms of E. coli vary, but include may include stomach cramps, fevers, bloody diarrhea and vomiting among others.
The CDC has not pinpointed the exact source of the outbreak, but the lettuce appears to have been contaminated with Shiga toxin-producing E. coli O157:H7, a particularly unsafe strain of the bacteria..