WASHINGTON (AP) — Parasitic illness cases linked to recalled iceberg lettuce have now been confirmed in 20 states, federal health officials said Thursday, expanding the scope of the largest outbreak of its kind in the U.S.

The Food and Drug Administration said government scientists have now identified cases in three additional states: Georgia, Tennessee and Texas.

The tally of people sickened by the parasite is now 11,458, up from about 10,900 reported last week.

The FDA, Centers for Disease Control and Prevention and state health officials have focused their investigation on lettuce grown at a farm in central Mexico operated by Taylor Farms, a major U.S. produce supplier.

The FDA said its staffers are continuing to inspect and test produce at the farm, in cooperation with officials from the Mexican government. The U.S. agency said it "remains confident that all recalled iceberg lettuce related to this specific cyclospora outbreak is off the market."

Cyclospora is a microscopic parasite that commonly causes watery diarrhea "with frequent and sometimes explosive bowel movements," according to the CDC. Outbreaks tend to occur most often in the late spring and summer.

The heat-loving parasite infects the bowels and spreads through feces. The illness, called cyclosporiasis, is less common than foodborne illnesses caused by other germs, including salmonella and E. coli. Many cyclospora cases are never linked to a specific food or other source.

Earlier this week, the CDC reported that there have been about 29,000 confirmed or suspected cyclospora cases in the U.S. this year. There have been 922 hospitalizations, according to the agency. Previously, the worst year in the U.S. for infections was 2019, when about 4,700 illnesses were reported nationally.

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